Seminars - Melbourne
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To schedule a CAWCR seminar, contact the
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Here are details of how to access the shared calendar in Outlook (internal use only) to view available seminar time slots.
CAWCR SEMINARS 2014
|Wednesday 17th December
||Intercomparison of the JULES and CABLE land surface models through assimilation of remotely sensed soil moisture
|Wednesday 3rd December
||Stratocumulus radiative effect, multiple equilibria of the boundary layer, and the transition to shallow-convective cumuli
||University of Auckland
|Wednesday 19th November
||Role of large scale moisture
advection for simulation of the MJO with increased entrainment
|Friday 14th November
||Development and testing of an on-demand, downscaled coastal wave guidance system
||Andre van der Westhuysen
|Thursday 13th November
||Impact of air-sea flux and boundary layer parameterizations on the intensity and structure of tropical cyclones
||Pennsylvania State University
|Thursday 6th November
||Why do model tropical cyclones intensify more rapidly at low latitudes?
||University of Munich
|Wednesday 29th October
||Seasonal Forecasting to Support the Management of Wild Fisheries and Aquaculture in Australia
|Tuesday 28th October
||Sustainability and reproducibility: Not just a good way to do software, a great way to do Science!
||Argonne National Lab
|Tuesday 28th October
||Generating Climate Information for Climate Adaptation for Indian Ocean Islands
|Wednesday 22nd October
||Past and future changes to inflows into Perth (Western Australia) dams
|Wednesday 15th October
||Radar-observed Mass-flux characteristics of tropical cumulus clouds: Computation based on traditional GCM definition of mass flux
|Monday 13th October
||Rose & Cylc in Environmental Forecasting at NIWA
|Friday 03rd October
||Iceberg forecasting from days to decades (ICECAST)
||University of Southampton
|Wednesday 1st October
||Developing a seamless modelling system in partnership
||UK Met Office
|Wednesday 1st October
||Improved numerical weather predictions by using optimised urban model parameter values and satellite derived tree heights
|Wednesday 17th September
||Investigating relationships between severe weather and East Australian Current eddies during east coast lows
|Wednesday 10th September
||Understanding MJO dynamics and model bias in CINDY/DYNAMO hindcasts
||Colorado State University
|Monday 08th September
||The Current Risk of Irreversible Climate Tipping Points
||Australian National University
|Wednesday 3rd September
||The Coastal Convective Interactions Experiment
||University of Queensland
|Thursday 21st August
||On the transition of nowcasting science into a service: Designing the operational plan for the Sydney Forecast Demonstration Project
||Alan Seed and Aurora Bell
|Wednesday 20th August
||A close shave with Occam's razor: managing complexity in a radar rainfall estimation system
|Wednesday 13th August
||Self-energy stochastic subgrid modelling in simulations of quasi-geostrophic and boundary layer flows
||Monash University / CSIRO
|Monday 11th August
||The Shipboard Automated Meteorological and Oceanographic System (SAMOS) Initiative
||Center for Ocean-Atmospheric Prediction Studies, FSU
|Wednesday 6th August
||On the application of STEPS2 over Australia: Seamless Rainfall Forecasting
|Wednesday 30th July
||A Low-Cost Probe for the Thermodynamic Phase of Cloud Particles
||University of Adelaide
|Thursday 24th July
||Cumulus clouds above Dominica and their response to cloud-layer humidity variations
|Monday 21st July
||An overview of the Centre for Climate Research Singapore: Our strategy and research plans
||Centre for Climate Research Singapore
|Wednesday 16th July
||New Storm Tide Decision Support Products for use in Emergency Management, Queensland
||Griffith Centre for Coastal Management, Griffith University
|Wednesday 2nd July
||NexGen project: Past, present and future - a CAWCR team perspective
|Friday 27th June
||Cloud products development for Himawari-8/9
||Meteorological Satellite Center, JMA
|Wednesday 25th June
||Tropical cyclone intensity and surface wind structure estimation and formation detection using the Deviation Angle Variance Technique
||University of Arizona
|Tuesday 17th June
||Wave-induced Boundary-Layer Separation and Atmospheric Rotors
|Thursday 12th June
||CMIP6 - Experimental design proposal and invitation for feedback
|Tuesday 10th June
||ENSO-AIR: The atmospheric dynamics of ENSO
||ARC Centre of Excellence in Climate System Science, Monash University
|Wednesday 28th May
||Overview of the perspective algorithms for signal processing, calibration, and data analysis for operational dual-polarization weather radars
||University of Oklahoma and National Severe Storms Laboratory
|Monday 26th May
||Future projection of ocean wave climate based on Japanese MRI-AGCM3.2 ensemble experiments
||Kyoto University, Japan
|Friday 23rd May
||On the rates of record setting in Australian monthly and seasonal temperature time series
|Friday 9th May
||Earth System Modelling for Climate Change
||Indian Institute of Tropical Meteorology
|Wednesday 7th May
||Advances in ocean forecasting - outcomes from the BLUElink-3 project
||Peter Oke and Gary Brassington
|Monday 5th May
||Monitoring and Forecasting Visibility in Canada
||Weather Impacts Technology Incorporated
|Wednesday 30th April
||Google Scholar: track your citations and search for papers
|Friday 4th April
||Identifying East Coast Lows in reanalyses and models
||BoM Climate Information Services / UNSW
|Wednesday 2nd April
||The Role of Soil Moisture and SSTs in Decadal Drought in Western North America
||CIRES/ATOC, University of Colorado
|Friday 14th March
||Unified Model development: recent progress and future strategy
||Director of Science, UK Met Office
|Wednesday 12th March
||An Assessment of Methods for Operational Mixing Height Determination; and the Southwest Monsoon and Fire Activity
||Desert Research Institute, Nevada
|Friday 7th March
||Intraseasonal Predictability and Dynamical Processes: the MJO and NAO two-way global interaction
||Deputy Director of Weather Science, UK Met Office
|Wednesday 5th March
||The Pilot National Heatwave Forecasting System
|Friday 28th February
||Fast and slow response of sea ice and the Southern Ocean to ozone depletion
||University of Washington
|Wednesday 26th February
||Influence of Amplifying Rossby Waves on Tropical Cyclone Intensity, Structure and Rainfall
|Monday 24th February
||UM status, plans & collaboration update
||UK Met Office
|Friday 21st February
||Atmospheric dispersion and air quality research and services at the Met Office
||UK Met Office
|Thursday 20th February
||Effects of declining aerosols in CMIP5 projections
|Wednesday 19th February
||Probabilistic prediction with deterministic models
||University of Helsinki
|Wednesday 19th February
||Representing tropical convection in weather and climate models - the need and opportunities for a revolution
||ARC Centre of Excellence in Climate System Science, Monash University
|Wednesday 12th February
||The emerging IIOE-2, an exciting international scientific initiative five decades on from the original International Indian Ocean Expedition (IIOE) of the 1960s
|Wednesday 5th February
||Is there a causal link between moistening preceding deep convection and cumulus congestus clouds?
||Monash University / CAWCR
|Wednesday 22nd January
||Climate Impact of the Antarctic ozone hole: long-term trend and inter-annual variability
||School of Earth and Environmental Sciences, Seoul National University
|Monday 20th January
||Findings from sustained observations off northern Chile - the long (trends) and the short (diurnal)
||Woods Hole Oceanographic Institution
The venue is the seminar room (Floor 9, east side) at 700 Collins Street, Docklands
Seminars are run typically with duration
of 30 to 45 minutes + questions. Dates and times are shown. If you are a vistor to the Bureau, you need to register at reception in the foyer.
For further details contact the
Wednesday 17th December, 11:00am - 12:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Intercomparison of the JULES and CABLE land surface models through assimilation of remotely sensed soil moisture
Numerous land surface models exist for predicting water and energy fluxes in the terrestrial environment. These land surface models have different conceptualizations (i.e., process or physics based), together with structural differences in representing spatial variability, alternate empirical methods, mathematical formulations and computational approach. These inherent differences in modeling approach, and associated variations in outputs make it difficult to compare and contrast land surface models in a straight-forward manner. While model intercomparison studies have been undertaken in the past, leading to significant progress on the improvement of land surface models, additional framework towards identification of model weakness is needed. Given that land surface models are increasingly being integrated with satellite based estimates to improve their prediction skill, it is practical to undertake model intercomparison on the basis of soil moisture data assimilation. Consequently, this study compares two land surface models: the Joint UK Land Environment Simulator (JULES) and the Community Atmosphere Biosphere Land Exchange (CABLE) for soil moisture estimation and associated assessment of model uncertainty. A retrieved soil moisture data set from the Soil Moisture and Ocean Salinity (SMOS) mission was assimilated into both models, with their updated estimates validated against in-situ soil moisture in the Yanco area, Australia. The findings show that the updated estimates from both models generally provided a more accurate estimate of soil moisture than the open loop estimate based on calibration alone. Moreover, the JULES output was found to provide a slightly better estimate of soil moisture than the CABLE output at both near-surface and deeper soil layers. An assessment of the updated membership in decision space also showed that the JULES model had a relatively stable, less sensitive, and more highly convergent internal dynamics than the CABLE model.
Wednesday 3rd December, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Stratocumulus radiative effect, multiple equilibria of the boundary layer, and the transition to shallow-convective cumuli
University of Auckland
Cloud radiative cooling at the top of the stratocumulus has long been thought to be important to power turbulence in the well-mixed, stratocumulus-capped boundary layer. The present work will present Large-Eddy Simulations that show that cloud-top radiative cooling is actually crucial to the existence of a stratocumulus in equilibrium. This equilibrium is distinct from a cloud-free equilibrium that exists for the same large-scale conditions and forcings. If sea surface temperature is increased, the stratocumulus equilibrium becomes unstable, while the cloud-free equilibrium becomes a shallow-convective layer topped by cumuli. This shows that the transition from stratocumulus decks in the eastern subtropical oceans to the trade-wind shallow-convective regions is essentially a transition from one basin of attraction to the other.
How finely the cloud radiative effect has to be represented is also investigated. Consequences for the parameterization of the boundary-layer clouds in larger-scale models will be discussed.
Wednesday 19th November, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Role of large scale moisture advection for simulation of the MJO with increased entrainment
The intraseasonal moisture budget is analyzed in simulations with the ACCESS climate model, which produces a reasonable representation of the Madden-Julian Oscillation when the entrainment rate in the convective parameterization is increased by 50%. Analysis of the moisture budget shows that parameterized convection tends to dry the troposphere and that large scale vertical advection moistens the troposphere. These two tendencies mostly balance each other. However, the total moisture tendency is asymmetric relative to the maximum precipitation, corresponding to the recharge and discharge process of organized convection in the Tropics. This moistening before and drying after the maximum precipitation is largely due to large-scale horizontal advection of moisture. By comparing to the control run that does not simulate a realistic MJO, we find that increasing the entrainment acts to reduce deep convection in the relatively dry environment by increasing the mixing of the dry air. As a result, large scale convection and large-scale advective processes play a stronger role during the development stage, which implies that convection is necessarily better organized.
Friday 14th November, 10:00am - 11:00am, Conference Room 3, 6th floor, 700 Collins St
Development and testing of an on-demand, downscaled coastal wave guidance system
Andre van der Westhuysen
In order to meet the increasing demand for high-resolution nearshore marine forecast products, NOAA's National Weather Service is developing the Nearshore Wave Prediction System (NWPS). This system is designed to provide on-demand guidance of nearshore wave conditions and related coastal hazards to forecasters. It was originally designed to run locally at Weather Forecast Offices (WFOs), using as primary forcing locally-produced the wind forecast fields. Additional inputs include offshore wave boundary conditions from NCEP's global WAVEWATCH III, and current and water level fields from NCEP's Real-Time Ocean Forecast System (RTOFS), P-Surge and Extra-Tropical Surge and Tide Operational System (ESTOFS). To benefit from economies of scale, NWPS has now been restructured to run on NCEP's central computing facility, while retaining its on-demand nature. This presentation will discuss the approach followed for implementing NWPS as an on-demand, cloud-based guidance system. This includes considerations for data flow, run scheduling and system loading on the central computer. Validation results for integral wave field parameters will be reviewed. In addition to these primary model outputs, NWPS incudes post-processing routines for producing wave partitioning and system tracking, and empirical wave run-up and rip current prediction. Examples and future plans for these products will be discussed.
Thursday 13th November, 2:00pm - 3:00pm, Conference Room 3, 6th floor, 700 Collins St
Impact of air-sea flux and boundary layer parameterizations on the intensity and structure of tropical cyclones
Pennsylvania State University
TCs are fueled by large fluxes of sensible and latent heat from the air-sea
interface. These fluxes (as well as momentum fluxes) cannot be explicitly
resolved by NWP models and therefore must be parameterized. Unfortunately,
there is a great deal of uncertainty as to the behavior of air-sea surface
fluxes, especially under strong (hurricane-force) winds. Thus, the numerous NWP
parameterizations of surface fluxes introduce model error into TC forecasts,
which limits the accuracy of predictions of TC intensity. In this talk, the
sensitivity of WRF-ARW simulated TCs to parameterizations of the surface
exchange coefficients for drag (Cd) and moist enthalpy (Ck) is examined. In
agreement with theory, increased Ck yields a stronger TC both in terms of
minimum central pressure and maximum 10-m wind speed. The impacts of Cd are not
as straightforward: increased drag does reduce the maximum 10-m wind speed (in
agreement with theory), but also deepens the minimum central pressure (opposite
of what is predicted by theory) -- in other words, Cd changes the pressure-wind
relationship of simulated TCs. Cd also profoundly impacts TC structure, such
that increased drag yields a more compact primary circulation.
Finally, some "Large Eddy Permitting (LEP)" simulations (run for 4-6 hours,
with dx as small as 111 m) of Hurricane Katrina (2005) are shown. These LEP
runs -- which use a nonlinear backscatter with anisotropy (NBA) subgrid-scale
parameterization scheme -- exhibit features resembling small-scale turbulence
for dx as large as 333 m. The size of these turbulent structures depends on dx,
indicating convergence to true LES has not been reached. That said, however,
the azimuthally averaged low-level secondary circulation is remarkably similar
between the LEP runs but considerably different than PBL runs at dx = 333 m:
the latter begin to undergo secondary eyewall formation whereas the former do
Thursday 6th November, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Why do model tropical cyclones intensify more rapidly at low latitudes?
University of Munich
I will examine the problem of why model tropical cyclones intensify more rapidly at low latitudes. The answer to this question touches on practically all facets of the dynamics and thermodynamics of tropical cyclones. The answer invokes the conventional spin up mechanism as articulated in classical and recent work together with a boundary layer feedback mechanism linking the strength of the boundary layer inflow to that of the diabatic forcing of the meridional overturning circulation.
The specific role of the frictional boundary layer in regulating the dependence of the intensification rate on latitude will be discussed. It will be shown that, even if the tangential wind profile at the top of the boundary layer is held fixed, a simple, steady boundary layer model produces stronger low-level inflow and stronger, more confined ascent out of the boundary layer as the latitude is decreased, similar to the behaviour found in a time-dependent, three-dimensional numerical model.
In an azimuthally-averaged view of the problem, the most prominent quantitative differences between the time-dependent simulations at 10°N and 30°N are the stronger boundary layer inflow, the stronger ascent of air exiting the boundary layer, together with the much larger diabatic heating rate and its radial gradient above the boundary layer at the lower latitude. These differences, in conjunction with the convectively-induced convergence of absolute angular momentum, greatly surpass the effects of rotational stiffness (inertial stability) and evaporative-wind feedback that have been proposed in some prior explanations.
Wednesday 29th October, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Seasonal Forecasting to Support the Management of Wild Fisheries and Aquaculture in Australia
Seasonal forecasting has great scope for use in marine applications, particularly those with a management focus. Seasonal forecasts from dynamical ocean-atmosphere models of high risk conditions in marine ecosystems can be very useful tools for managers, allowing for proactive management responses. The Australian Bureau of Meteorology.s seasonal forecast model POAMA currently produces operational real-time forecasts of sea surface temperatures for Australia. These forecasts are used in the management of multi-species long-line fisheries on the east coast of Australia. Southern bluefin tuna (SBT) are a quota-managed species in the eastern Australian longline fishery, and there is a management need to reduce non-quota capture of this species. Ocean forecasts are combined with a statistical habitat model to produce experimental habitat maps for fisheries authorities to use in regulating fishing effort. Similarly, POAMA forecasts around Tasmania, Australia, are utilised by managers of salmon aquaculture farms, with information used to manage feed composition, stocking densities and freshwater bathing, all of which enhance farm production in a variable climate. Warm summers can significantly impact farm production via an increase in operational expenses and impacts on fish condition, mortality and recovery potential, while cool winters slow salmonid growth. Forecast products have also been developed for prawn aquaculture in Queensland, based on air temperature and rainfall predictions for up to four months into the future. Advance warning of suboptimal conditions allows for proactive management responses and helps maintain industry profitability in an uncertain environment. Improved management of marine resources, with the assistance of such forecast tools, is also likely to enhance their resilience and adaptive capacity under climate change
Tuesday 28th October, 2:00pm - 3:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Sustainability and reproducibility: Not just a good way to do software, a great way to do Science!
Argonne National Lab
Back in the day of our mentors and our mentor's mentors science could be done with a grease pencil and transparency. These days we all code in order to get the most value out of the avalanche of data that is presented to us. The problem is much of this code is assigned to the dustbin of history, if you can even find it.
This seminar outlines the approach of the ARM program to product development on data from the 5 and 3cm wavelength polarimetric radars. Rather than a traditional product approach our team has developed a flexible, user configurable architecture for data QC and retrieval: The Python-ARM Radar Toolkit . More than just open source Py-ART is a community based code where, using GitHub, our users are able to submit changes or even start a whole new branch. By combining version control, unit testing and a common data model approach Py-ART increases the impact of the code we use by allowing other to find it, use it and improve it. Furthermore, through collaboration with the European radar community we have added ODIM5 support which makes it compatible with future Australian radar formats.
This presentation will be detailed based with many practical uses of Py-ART presented as well as lessons learned in radar QC and also a quick data centric overview of radar polarimetry.
Tuesday 28th October, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Generating Climate Information for Climate Adaptation for Indian Ocean Islands
The information needed for climate adaptation extends beyond what is typically generated for large scale climate analysis especially in regions with marked spatial variation in climate. The notion that one may downscale global scale information to obtain the information needed is quickly found out by engaging with adaptation practioners.
This presentation reports on the quest to generate information for adaptation at time scales from sub-seasonal to multiple decades for Sri Lanka, Maldives and the Comoros. Sri Lanka is an island of 250 km x 400 km with 2.5 km mountains. Working with River basin Authority, we have been providing a weekly climate advisory for users in water resources, agricultural, environmental, and public health management. The challenges in Maldives are different given its 1200 scattered low-lying coral reef based islands. We have been working with the Meteorological Service in providing a monthly climate advisory. Recently, we started supporting a program of fisheries development in Comoros. All these islands are in a region whose climate is inadequately studied, have modest scientific infrastructure and a shortage of scientists to address the unique adaptation challenges their societies face. In this presentation, I shall provide some examples of successfully generating information to meet user needs and other examples where we fall short.
Wednesday 22nd October, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Past and future changes to inflows into Perth (Western Australia) dams
SWWA has experienced a prolonged decline in rainfall since the early 1970s accompanied by serious reductions to inflows into the major storage systems. Consequent research questions include: What caused the decline in rainfall? Why have inflows decreased so dramatically? What can be expected over the coming decades? In this study, we consider these questions making use of recent observations and the latest generation of climate model results which attempt to simulate the effects of increased greenhouse gas concentrations.
Recent observations show a continuation of dry conditions and confirm that a significant change in the relationship between rainfall and inflows appears to have occurred. There is little evidence that increasing local temperatures alone can explain this changed relationship which possibly represents long-term physical changes (e.g. groundwater levels) to the catchments. There is a strong consensus amongst recent model results that rainfall will decline further by the end of the 21st century. While this confirms findings from studies of previous model results, for the purposes of better estimating future changes to inflows it may now be more important to understand the reasons for the changed rainfall/inflows relationship.
Wednesday 15th October, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Radar-observed Mass-flux characteristics of tropical cumulus clouds: Computation based on traditional GCM definition of mass flux
Cumulus parameterizations in weather and climate models frequently apply mass-flux schemes in their description of tropical convection. Mass-flux constitutes the product of the fractional area covered by convection in a model grid box and the vertical velocity in the convective clouds. Vertical velocity is difficult to observe making the evaluation of mass-flux schemes difficult. Here, two radar-based approaches are used to determine the vertical velocity and mass flux associated with cumulus clouds. The first approach uses the direct vertical velocity measurements from a pair of vertically pointing wind profilers but estimates the area fraction using a temporal aggregation. The second approach uses vertical profiles of radar reflectivity (VPRR) measurements from a scanning C-band radar to estimate for the vertical velocity. The field-of-view of this C-band radar contains the wind profiler pair. Therefore we used the direct vertical velocity measurements from the wind-profiler to train the VPRR from the C-band radar to provide estimates of vertical velocity. Scanning radars provide the best direct estimates of fractional area over a model size grid box. We also evaluate the sensitivity of mass flux and its components to different cumulus cloud types and to changes in the large-scale atmospheric conditions (CAPE, CIN, environmental humidity and large-scale vertical motions).
Monday 13th October, 11:00am - 12:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Rose & Cylc in Environmental Forecasting at NIWA
Hilary Oliver is lead developer of the open source Cylc Suite Engine, a modern cycle-interleaving meta-scheduler. Cylc is used operationally at NIWA, the UK Met Office, and the Marine Meteorology Division of the US Naval Research Laboratory, and by several NWP and climate research groups around the world. Rose, the new suite configuration and management framework for the Unified Model, supports cylc as its official meta-scheduler. Hilary will give an overview of how Rose and cylc are used at NIWA, and of the benefits they bring to NIWA's research and operational environmental forecasting systems.
Friday 3rd October, 10:30am - 11:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Iceberg forecasting from days to decades (ICECAST)
University of Southampton
An iceberg model (ICB) has been coupled to ocean models based on the Nucleus for European Modelling of the Oceans (NEMO), and the global 0.25 degree resolution ORCA025 implementation in particular. This NEMO-ICB configuration provides the option for running the ocean model with interactive icebergs, allowing feedback between the ocean and icebergs that may influence the coupled system on decadal timescales. On shorter timescales, NEMO-ICB is being used to investigate the drift of individual giant icebergs. One such iceberg is B31, roughly the size and shape of Singapore, which calved from Pine Island glacier (PIG) into the Amundsen Sea off west Antarctica during July 2013. We have tracked B31 in satellite images since November 2013, when B31 started to move northwards. By early September 2014, B31 was located about 300 km north of PIG. The subsequent trajectory of B31 is highly uncertain. One possibility is further northward drift into the Antarctic Circumpolar Current, followed by swifter eastward drift into the South Atlantic, a scenario that would unfold over the next year or so. In partnership with the UK Met Office, we are now developing NEMO-ICB within existing forecast systems (FOAM, GloSea5, HadGEM3) to track multiple giant icebergs in both hemispheres
Wednesday 1st October, 3:00pm - 4:00pm, Conference Room 3, 6th floor, 700 Collins St
Developing a seamless modelling system in partnership
UK Met Office
I will update you on the progress of the development of the Met Office forecasting and science strategy related to modelling. I will then talk of some recent work I have been involved in with GASS and the Met Office to evaluate the continental warm bias in global models. In addition I will provide some updates on work to evaluate the physical processes in regional and global models during two MJO events.
As head of Met Office Science Partnerships Jon is responsible for the Met Office's national and international relationships with other science organisations. This includes their Unified Model partnerships, their relationship with UK research councils such as NERC, their academic partnerships with Universities in the UK and a growing range of other key international strategic partners. Jon has a background in physical modelling and parametrizations and leads the Global Atmospheric System Studies WMO group who coordinate these activities internationally. Specific areas of focus during the last 20 years have included clouds, radiation, microphysics and convection.
Wednesday 1st October, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Improved numerical weather predictions by using optimised urban model parameter values and satellite derived tree heights
About 90% of the Australian population lives in urban areas yet numerical weather prediction (NWP) systems poorly represent urban areas. The Australian Community Climate and Earth System Simulator (ACCESS) uses a simple urban model with only three parameters; heat capacity, albedo and aerodynamic roughness length. The urban model parameters are set fixed to the same values at all urban areas, worldwide. This urban model was developed in the United Kingdom and consequently the default urban parameter values are unlikely to be appropriate for Australia. A previous study has used observations of surface fluxes from Mexico City and Vancouver to evaluate this urban model and concluded that much better estimates of the sensible heat flux are provided when a significantly smaller value for the urban heat capacity parameter is used. This urban model contains no information about the three dimensional morphology of the buildings and consequently the urban heat capacity parameter is not well defined and cannot be measured.
The ACCESS NWP system simply assumes that over most of Australia, including urban areas, trees are 28 meters tall. ACCESS NWP assumes that the heat capacity of trees increases with tree height and follows a power law while the aerodynamic roughness length increases linearly with tree height. A halving of model tree heights causes the heat capacity of model trees to reduce by a factor of almost six.
In this study we use revised urban model parameter values that are more appropriate for Australia and a global dataset of forest canopy height derived from satellite Lidar measurements to improve the ACCESS NWP system. Experiments show that the use of the new urban model parameters and tree heights results in significantly improved forecasts of air temperature at a height of 2 meters above the surface (screen level).
Wednesday 17th September, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Investigating relationships between severe weather and East Australian Current eddies during east coast lows
The relationships between sea surface temperature (SST) distribution and thunderstorms, heavy rainfall, and sea level pressure, during four east coast lows are examined using both lightning observations and numerical simulation results. Atmospheric changes caused by the introduction of complex eddy and frontal structures present in Bluelink ocean datasets are investigated using the Weather Research and Forecast model. Maximum convective available potential energy (MCAPE) differences between Bluelink SST simulations and coarse SST simulations indicate that areas of greater MCAPE in the Bluelink simulations are related to regions of warmer waters with horizontal advection often displacing increased MCAPE downwind. At short timescales of 3 to 6 hours, the differences in MCAPE become larger and more localized and show a compelling correlation with observed lightning. For the damaging Pasha Bulker case, a plume of thunderstorms associated with the coastal damage occurs downwind of a region of enhanced MCAPE, increased rainfall, and lower sea level pressure, along the southern flank of a warm eddy. Based on these results it is concluded that the particular features of the warm eddy enhanced the thunderstorm potential over the coastal region and helped in localising the area of greatest impact.
Wednesday 10th September, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Understanding MJO dynamics and model bias in CINDY/DYNAMO hindcasts
Colorado State University
Weather forecasting and climate models demonstrate severe deficiencies in simulating the Madden-Julian oscillation (MJO), even though simulation of this phenomenon is important for the prediction of rainfall variability and extreme events in both the tropics and higher latitudes. Many global models that can produce a realistic MJO are plagued by substantial mean state biases, especially in models where simple fixes to improve intraseasonal variability are employed. This talk will describe a process-oriented diagnosis of hindcast MJO events during the Fall of 2011, the period of the CINDY/DYNAMO field project in the Indian Ocean. Three atmospheric GCMs are employed, including the NCAR Community Atmosphere Model 5 (CAM5), a superparameterized version of CAM (SP-CAM), and the Ocean-Atmosphere-Land Model (OLAM) that allows regional mesh refinements. Vertically-integrated moist static energy budget analysis will demonstrate that simple fixes to improve MJO activity in global models may produce realistic variability for the wrong reasons, and can help explain the substantial mean state biases in these models. Critical processes that models must get right to properly simulate both the mean state and variability will be discussed. Future diagnostic directions that better employ vertical structure information will also be explored.
Monday 08th September, 10:30am - 11:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
The Current Risk of Irreversible Climate Tipping Points
Australian National University and The University of Queensland
The question of tipping points is of critical importance since it affects
future climate projections and adaptation plans. The history of the Earth
climate is dominated by abrupt shifts in state of the atmosphere-ocean-ice
sheets system, including sharp warming episodes during glacial states (termed
"interstadials") and rapid freezing events during warm periods (stadials).
Examples include abrupt warming spikes during the last glacial (~100 000 to 20
000 years-ago) and the abrupt collapse of the North Atlantic Thermohaline
Circulation (for example 12900 11700 years ago and 8500 years ago). The
current rise in greenhouse gas-induced energy level of the atmosphere (from 280
ppm CO2 in the 18th century to 401.85 ppm in March 2014), reaching about +3
Watt/m2, at a rate of 2 to 3 ppm/year, is unprecedented in the geological
record of the last 65 million years, posing an existential danger to numerous
species and to human civilization. The extreme rate of global warming would
retard the ability of many species to adapt. Already signs of future tipping
points are manifested by the acceleration of extreme weather events around the
globe. A continuation of current emissions will result in large parts of the
continents becoming unsuitable for agriculture, sea level rise on the scale of
many meters, and ocean acidification threatening a collapse of the marine food
chain. There is no alternative to global effort at deep cuts of carbon
emissions coupled with fast-tracked CO2 sequestration through forest regrowth,
biochar and chemical methods.
Wednesday 3rd September, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
The Coastal Convective Interactions Experiment
University of Queensland
The Coastal Convective Interactions Experiment (CCIE) aims to understand the mechanisms and significance of interactions between the sea breeze circulation and pre-existing convective storms over South East Queensland, Australia. Sea breeze - deep convective interactions are frequently associated with the most destructive storm events and still remain a significant challenge for forecasters. To tackle these research questions, a high resolution (1x1km) 17 year radar derived climatology of thunderstorm activity was developed to supplement a multi-year field campaign which utilises a wide range of instrumentation including Doppler scanning lidar and mobile x-band radar. Preliminary results from the climatology analysis and 2013 CCIE field campaign will be presented.
Thursday 21st August, 09:30am - 10:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
On the transition of nowcasting science into a service: Designing the operational plan for the Sydney Forecast Demonstration Project
Alan Seed and Aurora Bell
The Strategic Radar Enhancement Project (SREP) NPP Science Programme has developed a suite of new scientific capabilities with the potential to improve the Bureau's ability to produce timely and skilful forecasts and warnings in the 0-12 hour lead time. A 1.5 km version of ACCESS NWP that assimilates radar data and is updated on an hourly cycle (ACCESS1.5) has been developed and tested. The SREP Science Programme also significantly upgraded Rainfields radar based quantitative precipitation estimation (QPE) and radar quality control tools. The five radars in the Sydney area were upgraded to provide data over a test-bed domain large enough to test the impact of radar data assimilation on the accuracy of ACCESS1.5. The objective of the SREP Science Programme was to undertake research and development and the NPP did not include funding for operational implementation of these new capabilities.
The Sydney Forecast Demonstration Project is a structured collaboration between the Weather Policy Branch, NSWRO, ISS, and CAWCR. Its aim is to demonstrate the potential for leveraging the new SREP Science capabilities to improve operational forecasts and warnings during a 10-week trial of real-time forecasting. A number of Bureau systems have been adapted so as to utilise the ACCESS1.5 model output or the enhanced radar output from Rainfields3 as part of this FDP.
This seminar will provide details on the FDP and use the experience that has been gain thus far in designing the operational plan for the Sydney FDP to discuss the vexed issue of how to transition science into operations.
Wednesday 20th August, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
A close shave with Occam's razor: managing complexity in a radar rainfall estimation system
The Bureau of Meteorology is in the final stages of an upgrade to Rainfields, the operational radar quantitative precipitation estimation (QPE) and nowcasting system for the Australian radar network. Radar reflectivity quality control is a key element to Rainfields and includes radar echo identification and corrections for partial occultation, attenuation, and bias due to the vertical profile. The radar reflectivity that is observed aloft is extrapolated to the ground using an anisotropic 3D Kriging algorithm that recognizes the difference between the structure of the reflectivity in the vertical and horizontal and generates a measure for the extrapolation error. Thereafter the surface reflectivity is converted into rainfall using the climatological Z-R relationship for the radar and accumulated over the 6-minute time step.
The Bureau operates a network of 1700 real-time rain gauges that report at 30-minute intervals. The bias at each gauge under a specific radar is updated in real-time using a Kalman filter and a field of adjustment factors for each radar is derived through a Kriging interpolation. Thereafter the multi-radar mosaics are constructed using the error fields that were generated while extrapolating the reflectivity to the surface. The performance of the QPE system is monitored in real-time and summary statistics of QPE error for each radar are generated each month.
Occam's razor, "Everything should be as simple as possible, but not simpler", was major design consideration in the development of the QPE algorithms. In general, simple algorithms are more robust than overly complex alternatives that require large quantities of high quality observations to provide the occasional benefit at the cost of increased computation and parameterization. The least complex option for each stage in the processing chain was investigated first and complexity was only added once it was demonstrated that the more complex algorithms were delivering benefits. The Australian radar network contains 70 radars and Rainfields generates around 4000 products per hour.
Therefore a great deal of thought was spent on optimizing the various algorithms for computation speed, which necessarily implied that complexity was kept to a minimum. Not all Australian radars are equal and in general simpler algorithms were assigned to the older radars which did not have the capability to support the more advanced algorithms. This flexibility with the processing chain was made possible by having a system that was highly configurable where both algorithms and parameters could be assigned to a specific radar.
This presentation will provide an outline of the Rainfields' algorithms and use them to illustrate the issues of managing complexity in a heterogeneous radar network that covers a continent.
Wednesday 13th August, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Self-energy stochastic subgrid modelling in simulations of quasi-geostrophic and boundary layer flows
Monash University / CSIRO
Stochastic model representations are presented of the subgrid turbulence interactions in simulations of three-dimensional boundary layer, and quasi-geostrophic atmospheric and oceanic flows. In geophysical simulations it is not possible to resolve all of the scales of motion, instead one must resort to large eddy simulation (LES), where the large eddies are resolved on a computational grid and the unresolved subgrid interactions are parameterised. If these interactions are not parameterised self-consistently, then the results become resolution dependent. In typical approaches one starts with an hypothesis, often motivated by physical considerations, that then leads to a subgrid model. In contrast I will present a new self-energy (SE) stochastic subgrid modelling approach in which the model coefficients are determined from the subgrid statistics of a high resolution reference simulation, with physical interpretations made apostiori. The stochastic SE subgrid model consists of a meanfield shift, deterministic drain dissipation acting on the resolved field and a stochastic backscatter force. Subsequent LESs using these coefficients reproduce the statistics of the higher resolution simulations across all scales of motion. In addition as no assumptions are made on the structure of the subgrid model, physical interpreations can be made from the subgrid coefficients themselves concerning the transfer of energy between eddies of varying scale.
Monday 11th August, 10:30am - 11:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
The Shipboard Automated Meteorological and Oceanographic System (SAMOS) Initiative
Center for Ocean-Atmospheric Prediction Studies, FSU
As the chairman of the SAMOS initiative, the author will provide an overview of this decade long project to acquire, quality control, and distributes underway surface meteorological and oceanographic observations from over 30 oceanographic research vessels. Research vessels provide underway observations at high-temporal frequency (1 min. sampling interval) that include navigational (position, course, heading, and speed), meteorological (air temperature, humidity, wind, surface pressure, radiation, rainfall), and oceanographic (surface sea temperature and salinity) samples. Vessels recruited to the SAMOS initiative collect a high concentration of data within the U.S. continental shelf and also frequently operate well outside routine shipping lanes, capturing observations in extreme ocean environments (Southern, Arctic, South Atlantic, and South Pacific oceans).
The presentation will include information on the SAMOS data center.s activities to improve the quality of observations from research vessels. These include routine automated and visual data quality evaluation, feedback to vessel technicians and operators regarding instrumental errors, best practices for instrument siting and exposure on research vessels, and professional development activities for research vessel technicians.
Examples will include the application of quality-controlled SAMOS observations to evaluate weather reanalysis and ocean forecast models, validate satellite data products, and develop improved satellite retrieval algorithms. The seminar will conclude with an overview of a series of bulk turbulent flux estimates presently under development along individual research vessel
cruise tracks. The new flux products take full advantage of the data quality flags applied by the SAMOS data center. The bulk flux models that have been applied to the observations and preliminary comparisons of the output fluxes will be presented, including spatial and temporal coverage for the derived parameters.
The unique quality and sampling locations of research vessel observations and their independence from many models and products makes them ideal for validation studies. The strengths and limitations of research observations for validation studies will be discussed. The author welcomes input from the audience regarding potential applications for SAMOS observations and the soon to be operational SAMOS flux products.
Wednesday 6th August, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
On the application of STEPS2 over Australia: Seamless Rainfall Forecasting
The Australian Bureau of Meteorology uses a number of Numerical Weather Prediction (NWP) models to generate deterministic rainfall forecasts over a range of lead-times, each with a different resolution in space and time and with different forecast domains. The high resolution regional NWP models that are used to generate forecasts for the first three days are typically more accurate than the lower resolution Global NWP models that have forecasts for the longer lead times, so there is a requirement for a seamless forecast system that is able to blend the various NWP forecasts into a single forecast with a uniform resolution over the entire forecast period. NWP forecasts of rainfall contain errors at scales that are significant for even large river basins, and ensemble hydrological prediction systems require ensembles of the order of 100 members, which is well beyond the size that can be generated by NWP ensemble systems. The idea, therefore, is to blend the NWP models in such a way that recognises the skill of the NWP at a particular scale and lead time and to use a stochastic model of forecast errors to perturb the blended deterministic forecast to generate a large ensemble.
Two NWP models from the Bureau, ACCESS-G (Global) and ACCESS-R (Regional), are downscaled and blended to produce an ensemble of hourly forecasts out to 10 days. The spatial resolution of ACCESS-G is 0.5625 ° (~40 km) longitude, 0.375 ° (~40 km) latitude with a 3-hourly time step out to 10 days. ACCESS-A's spatial resolution is 0.11 ° (~12 km) longitude, 0.11 ° (~12 km) latitude with hourly time steps out to 3 days. These models are temporally interpolated, downscaled to a 2 km by 2 km grid, and blended over the 1000 km by 1000 km output domains. A 50 member ensemble of forecasts is produced.
A year of ensemble forecasts (accumulated to daily rainfall totals) have been verified against the daily Australian Water Availability Project (AWAP) analyses (0.05 ° x 0.05 ° resolution) that are based on an interpolation between rain gauges and show the system is able to produce reliable forecasts out to 5 days over these domains with appropriate ensemble spread.
Wednesday 30th July, 10:30am - 11:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
A Low-Cost Probe for the Thermodynamic Phase of Cloud Particles
University of Adelaide
The knowledge of the thermodynamic phase of cloud particles is important for aviation safety, and for correctly predicting the cloud--radiation interactions.
I will discuss our progress in developing an expendable instrument that can detect whether a cloud is composed of supercooled liquid droplets or ice crystals. It is a backscatter-sonde with polarimetric analysis of light that is backscattered to the instrument from the cloud particles. It is balloon-borne and accompanied by a radiosonde that takes care of the temperature measurements and telemetry. Prototypes have been launched (or operated) at various locations and I will discuss some of these results.
Thursday 24th July, 2:00pm - 3:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Cumulus clouds above Dominica and their response to cloud-layer humidity variations
The Dominica Experiment (DOMEX) was carried out in the eastern Caribbean in the spring of 2011. It included 21 research flights of the Wyoming King Air over and around the mountainous island of Dominica. During the six-week field campaign, higher amounts of precipitation were observed on Dominica under strong trade wind conditions while precipitation was suppressed under weak trade wind conditions. A number of hypotheses exist as to what controls precipitation on the steep slopes of Dominica.
In this presentation, I will present a summary of the research completed to date, and focus on 1) the influence of thermally- versus mechanically-driven orographic convection on cloud structure above the island; and 2) how observed day-to-day differences in the cloud-layer humidity influence cloud development. Aircraft observations above the island, a simple entraining-parcel model, large-eddy simulations of a thermally buoyant bubble and a climatology of balloon soundings from the neighboring island of Guadeloupe are used to examine the influence of these two factors. The results paint a complicated picture of the ingredients that shape convection and cloud development over Dominica. On the one hand, the speed of the incoming flow controls the convective regime and the vigor of mechanically-driven convection. On the other hand, the drier cloud layer on low wind days and the nature of the convection (e.g., the dominant width and frequency of convection) appears to have an important influence on cloud and precipitation development.
Monday 21st July, 3:15pm - 4:15pm, Conference Room 3, 6th floor, 700 Collins St
An overview of the Centre for Climate Research Singapore: Our strategy and research plans
Centre for Climate Research Singapore
Speaker Bio: As Director of the Centre for Climate Research Singapore, Dr Chris Gordon spearheads the establishment and capability-building of the Centre, and guides the climate and weather research programme.
After completing his PhD in theoretical physics, Dr Chris Gordon joined the UK Met Office in 1979 as a founder member of the Met Office's ocean modelling activity. Following a number of years working as a research scientist, in the mid-1980s, he moved to become head of the Met Office climate research activities based in the Hooke Institute at the University of Oxford. In 1989 he returned to the Met Office to lead the climate ocean activities in the newly formed Hadley Centre. During this time, he led the project which developed the Hadley Centre HadCM3 climate model, versions of which have been used extensively by the national and international climate research community.
From 2001 to 2005, he held a number of research senior management positions in the Met Office. These included Head of Oceans and Climate Research and Head of the Government Meteorological Research Programme. From 2006 until January 2012, Dr Gordon was Head of the Met Office Hadley Centre, the UK's main government climate research institution. Over a number of years, he has been instrumental in establishing a wide range of national and international strategic science partnerships. He moved to Singapore in April 2013
Wednesday 16th July, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
New Storm Tide Decision Support Products for use in Emergency Management, Queensland
Griffith Centre for Coastal Management, Griffith University
With impetus from the events of TC Yasi in 2011, Griffith University has undertaken a two-year project funded by the Queensland State government with the aim of improving the storm tide decision support system available to emergency managers during a tropical cyclone event. Storm tide presents the highest risk to life during a tropical cyclone event, and the major population centres along the Queensland coast have high exposure to this hazard. Presently, evacuation decisions must be made well prior of availability of accurate knowledge of cyclone landfall location and timing. The wide uncertainties in the cyclone track and intensity forecast limit the value of deterministic assessment of storm surge risk, further complicated by the importance of the phasing of the astronomical tide when storm surge strikes. An extensive stakeholder investigation into disaster management requirements highlighted the need for visual, high resolution storm tide risk products that provide a view of uncertainty at different lead times. In response, the QSurge storm tide decision support system have been developed, providing emergency managers with a tiered suite of products allowing visualisation of potential storm tide inundation impact from an approaching cyclone. Here we showcase this system, consisting of both a probabilistic forecast product and a potential envelope of inundation product. The cyclone ensemble methods and hydrodynamic modelling systems backing this product will be presented. Avenues for future development and stakeholder uptake will be discussed.
Wednesday 2nd July, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
NexGen project: Past, present and future - a CAWCR team perspective
The NexGen Forecast and Warning System project is on the cusp of achieving its vision of 'forecasts where you are, when you need them' with the rollout to NT in October. NexGen has provided massive modernisation, service and efficiency increases for most public and marine forecasts and warnings; a rapid path to operations for CAWCR developments; new dissemination infrastructure being utilised by the Bureau, downstream agencies and 3rd party providers; and operational calibrated probabilistic forecasts and guidance - all at a modest cost to the Bureau.
Some of CAWCR's key (collaborative) responsibilities include forecast process definition, forecast automation tools to produce derived grids, icons and text, and guidance-post-processing to provide a credible service and to support forecast production efficiency. Marrying sometimes problematic guidance with Service requirements can be a challenge.
This talk will highlight some NexGen outcomes. Past NexGen priorities - including balancing tension between infrastructure and features, or for example ACCESS-C in the GFE versus a TC forecast capability - will be discussed
With the rollout project winding up and resources shrinking, NexGen will focus on CAWCR and Bureau strategic priorities of verification to guide effort focus, routine forecast automation to provide a baseline for verification and to allow a greater severe weather focus and surge capacity, guidance post-processing for accurate but efficient forecasts, and infrastructure to support surge capacity - particularly through remote operation.
Friday 27th June, 2:00pm - 3:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Cloud products development for Himawari-8/9
Meteorological Satellite Center, JMA
Wednesday 25th June, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Tropical cyclone intensity and surface wind structure estimation and formation detection using the Deviation Angle Variance Technique
University of Arizona
Measuring critical parameters of tropical cyclones, which spend much of their life over the vast tropical oceans, is problematic. In situ
observations are useful if the tropical cyclone moves within their range, but they cannot provide the constant measurements necessary to properly monitor the tropical cyclone through its life. Remote-sensing technologies, particularly those on geostationary satellites, provide the best opportunity to consistently monitor tropical cyclones: however, they do not directly measure many of the parameters used to characterize tropical cyclone structure and intensity.
In this presentation we will introduce the deviation angle variance (DAV) technique, which measures the organization of cloud structures embedded in tropical cyclones from geostationary imagery. As the tropical cyclone develops and intensifies, the cloud structures become more organized and the DAV measures this organization . the lower the DAV value, the more axisymmetric the tropical cyclone. The DAV can be used to: differentiate pre-genesis cloud clusters; objectively estimate actual intensity of a tropical cyclone; and even (new) extract two-dimensional surface wind information. The calculation of the parameter will be described and we will show examples of each aspect of our technique and discuss future development.
Tuesday 17th June, 10:30am - 11:30am, Conference/Meeting Rooms, 6th floor, 700 Collins St
Wave-induced Boundary-Layer Separation and Atmospheric Rotors
Boundary layer is a region of fluid flow that is strongly affected by the no slip condition along the interface with a solid boundary. The aspect of boundary layer dynamics that represents the greatest difficulty theoretically is the flow separation. Laboratory experiments show that boundary layers show no tendency to separate where there the flow external to the boundary layer accelerates. However, where the external flow is strongly retarded, the boundary layer will separate from the solid surface. In stratified fluids, such as the atmosphere, this adverse pressure gradient and deceleration of the flow can be achieved through pressure perturbations induced by internal gravity waves launched by the flow over complex terrain. If that is the case, boundary-layer separation is said to be wave-induced. Attendant to wave-induced boundary-layer separation is the occurrence of terrain-induced atmospheric rotors. The latter have been traditionally described as horizontal vortices with an axis parallel to a mountain ridge and are often characterized by severe or extreme turbulence.
Two cases of mountain waves, rotors and the associated turbulence in the lee of the Medicine Bow Mountains in SE Wyoming have been investigated using aircraft observations. Analyzed measurements include observations from in situ sensors and high-resolution cloud radar on board the University of Wyoming King Air aircraft. High-resolution dual-Doppler syntheses of the two-dimensional velocity fields in the vertical plane beneath the aircraft reveal the boundary-layer separation, the scale and structure of the attendant rotors, and downslope windstorms. The analyzed radar measurements comprise the first direct atmospheric observations of the wave-induced boundary-layer separation. Numerical simulations with a mesoscale numerical model are used to facilitate dynamical interpretation of the observed phenomena.
Thursday 12th June, 10:00am - 11:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
CMIP6 - Experimental design proposal and invitation for feedback
The proposal for the CMIP6 experimental design has recently been published in EOS (Meehl et al., EOS, 2014, see below). The CMIP6 design includes a small set of experiments to be routinely performed by modeling groups whenever they develop a new model version, which will be referred to as the .CMIP DECK. experiments. Other Model Intercomparison Projects (MIPs) will build on the CMIP DECK experiments to address a broad range of scientific questions. These MIP experiments together with the CMIP DECK experiments will constitute the suite of simulations for CMIP6. The output from these experiments will be distributed for community use via the Earth System Grid infrastructure.
Feedback on this proposal is being solicited from modelling groups and model analysts. Jerry Meehl of the CMIP Panel has asked me to coordinate the CAWCR feedback. As a step towards this, seminars will be held at CMAR Aspendale, CMAR Hobart and CAWCR/Bureau, and possibly elsewhere depending on demand. The seminar will involve an approximately half hour overview of the CMIP6 initial proposal, followed by discussion both on aspects of the proposal itself and on further process that may benefit feedback.
The feedback on the proposed CMIP6 experimental design is to be submitted to the CMIP Panel by 15 Sept. 2014, and will be reviewed at the WGCM meeting in October 2014, where the CMIP6 experimental design is intended to be confirmed.
EOS article (Meehl et al., 2014): http://onlinelibrary.wiley.com/doi/10.1002/2014EO090001/abstract
WGCM CMIP6: http://www.wcrp-climate.org/index.php/wgcm-cmip/wgcm-cmip6
Tuesday 10th June, 2:30pm - 3:30pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
ENSO-AIR: The atmospheric dynamics of ENSO
ARC Centre of Excellence in Climate System Science, Monash University
ENSO is a coupled ocean-atmospheric chaotic damped oscillation, which in its most general form is often described by the Bjerknes feedbacks between SST, wind stress and the thermocline. Most research in the past has been somewhat focused on an oceanic point of view suggesting that the most important elements of the dynamics or in the ocean. Here I will present a view on ENSO that highlights the atmospheric dynamics important for ENSO. I will in particular discuss atmospheric feedbacks that cause the non-linearity and pattern diversity of ENSO and will discuss atmospheric cloud feedbacks which are in particular important to understand differences or error in model simulations.
Wednesday 28th May, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Overview of the perspective algorithms for signal processing, calibration, and data analysis for operational dual-polarization weather radars
University of Oklahoma and National Severe Storms Laboratory
Dual-polarization weather radars are becoming a standard for meteorological operational networks around the globe. The US National Weather Service has completed polarimetric upgrade of their 160 WSR-88D radars about a year ago and a similar upgrade is underway in several countries. In this talk, an overview of the most recent polarimetric radar algorithms and products which are either implemented or being tested at S, C, and X bands is presented. These include signal processing routines, calibration procedures, and the algorithms for classification of radar echo and quantitative precipitation estimation. The algorithms and products being developed and validated at NSSL for S-band WSR-88D radars and in the partnership between the University of Oklahoma and Enterprise Electronics Corporation for C- and X-band radars will be discussed.
Some novel technologies such as Spectrum-Time Estimation and Processing (STEP), utilization of specific attenuation for better rainfall estimation and absolute calibration of radar reflectivity, data-based calibration of reflectivity and differential reflectivity, advanced methods for attenuation correction, sea clutter identification, detection of hail and determination of its size, QPE compositing / networking using specific attenuation, and estimation of circular depolarization ratio with the radars with simultaneous transmission / reception will be described in more detail.
Monday 26th May, 9:30am - 10:30am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Future projection of ocean wave climate based on Japanese MRI-AGCM3.2 ensemble experiments
Kyoto University, Japan
Future projections of global and the North West Pacific ocean wave climate under global warming scenario was conducted and the uncertainties related with different Sea Surface Temperatures (SSTs) was investigated, based on SST-ensemble experiments performed by an atmospheric general circulation model (MRI-AGCM3.2H) and a wave model (WAVEWATCH III). The results yield future changes in seasonal mean wave height that are within about ± 0.4 m depending on the region and season. The future changes for summertime wave height in the Western North Pacific (WNP) are highly sensitive to SST conditions that are influenced by tropical cyclone changes. The results were applied to the Coordinated Ocean Wave Climate Project (COWCLIP) which is the latest multi-model wave ensemble product, generalizing the relationship between wave climate change and SST for the tropics. The spatial variation of SST in the tropical Pacific Ocean is a major factor in the wave climate changes for the WNP during summer.
Friday 23rd May, 2:30pm - 3:30pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
On the rates of record setting in Australian monthly and seasonal temperature time series
We describe the rates of new record setting over time for monthly, seasonal and annual temperature anomalies across Australia, using monthly temperature anomaly analyses of the Bureau of Meteorology's ACORN-SAT dataset, nationally and regionally averaged for the period 1910-2013. The site temperature data feeding into the analyses have been subjected to stringent quality control and homogeneity assessments. A new high record is deemed to have been set in our time series when the current value exceeds all the previous values, with new low records being defined analogously. By definition the first value of the time series represents a new record. This study is particularly focussed on how frequently such new records, both high and low, are set. We find that new high records are occuring at much higher rates than new low records, and in some cases new low records have become very scarce. In some parts of the country, there has been a burst of new high records in recent years, consistent with a warming climate.
Friday 9th May, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Earth System Modelling for Climate Change
Indian Institute of Tropical Meteorology
Building in-house capability for development of an Earth System Model (ESM) is crucial for understanding various scientific issues on Attribution and Projection of climate change and is one of the major objectives of the CCCR at the IITM. The approach adopted at IITM for ESM development is based on the concept of incorporating earth system components into the Climate Forecast System (CFS) coupled model, which is currently the base modelling framework for seasonal and extended range monsoon prediction in India. Keeping this in view, a group of scientists at CCCR have successfully developed and implemented the first version of ESM by incorporating a new ocean component (MOM4p1) in the CFS coupled model. MOM4p1 is a comprehensive ocean general circulation model with interactive ecosystem and biogeochemical processes. ESM1.0 (also known as the .CCCR-IITM climate model.) has been successfully tested and integrated for more than 100 years on the High Performance Computing (HPC) system at IITM. Results from the ESM1.0 long run indicate significant improvements in the simulation of sea surface temperature (SST) distribution as compared to the original CFS model. The improvements in SST simulation in ESM1.0, which prominently manifest in the subtropical Pacific, Atlantic and Indian Oceans, are found to result from better representation of ocean physical processes (e.g., vertical mixing, shortwave penetration, etc.). In addition, the ESM1.0 simulation captures important features of the El Nino / Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) variability and their links with the Indian summer monsoon. Furthermore, ESM1.0 also shows realistic features of the SST-chlorophyll variations associated with (a) Seasonal cycle of monsoon winds over the Indian Ocean (b) ENSO variability in the Pacific. The development of ESM1.0 is an important step towards understanding global and regional climate response to bio-geochemical processes and the mechanisms that control the ocean carbon cycle. Efforts are also underway to incorporate an interactive aerosol-chemistry transport module into ESM1.0.
Wednesday 7th May, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Advances in ocean forecasting - outcomes from the BLUElink-3 project
Peter Oke and Gary Brassington
Bluelink-3 is the third project in a partnership between the Bureau of Meteorology, CSIRO, and the Royal Australian Navy. June 2014 marks the ten-year anniversary of research and development under Bluelink. The goal of Bluelink is the development and implementation of capabilities in operational oceanography for Australia. Under Bluelink-3, the team has developed a new, near-global, eddy-resolving ocean prediction system; a data-assimilating, relocatable ocean-atmosphere-wave forecast system; a new coupled ocean-atmosphere prediction system with advanced (EnKF) data assimilation and a modelling system for the littoral zone, including beach morphology.
The new global ocean model extends the eddy-resolving resolution of OceanMAPS (BoM.s operational ocean prediction system) and BRAN (Bluelink ReANalysis) from a regional eddy-resolving system, covering just the Australiasian region, to a new-global eddy-resolving system, covering all longitudes and latitudes between 75S-75N. The Bluelink system was in three stages: (1) a 20-year free model run with no data assimilation; (2) a multi-year reanalysis; and (3) hindcast trial for operational implementation into the Bureau. The performance of the model, data assimilation and overall system through these stages will be reviewed. In addition, the interpretation of the forecast system as a time-lagged 4-cycle ensemble will be highlighted. Closely complementing these capabilities and developed through Bluelink investment are global analyses of sea surface temperature and sea level anomaly. Together these complementary sources of information provide a comprehensive view of the oceans state and circulation into the past, present and short-term future. Details of the global developments under Bluelink-3 will be described.
The global Bluelink prediction system underpins Bluelink.s forecasting and hindcasting capabilities. Nested within the global system is a relocatable ocean, atmosphere, wave forecast system called the Relocatable Ocean Atmosphere Model (ROAM). ROAM includes a graphical user interface that allows a non-expert user to autonomously initiate, configure, and execute forecasts. The underpinning ocean model includes an extensive set of stability controls, that adaptively adjust the model.s time-stepping, mixing levels, and parameterisations to ensure numerical stability. Details of ROAM, including the most recent developments under Bluelink-3 will be described.
Monday 5th May, 3:30pm - 4:30pm, Conference Room 3, 6th floor, 700 Collins St
Monitoring and Forecasting Visibility in Canada
Weather Impacts Technology Incorporated
In Canada, visibility is often restricted due to falling or blowing snow, rainfall, and either pure liquid or ice fog. A number of R&D projects have been conducted in Canada to improve the monitoring and forecasting of visibility. These include several projects where the author was a participant or PI, including the Canadian Airport Nowcasting (CAN-Now) project, the Science of Nowcasting Olympic Weather for Vancouver 2010 (SNOW-V10) and participation in the Forecast and Research in the Olympic Sochi Testbed (FROST-2014). From interactions with operational forecasters, it is clear that few tools existed before these projects to assist them in making forecasts. Today, there are several options available using a variety of different techniques, including the extensive use of conditional climatology, fuzzy logic, satellite data focussed methods, rule based systems, and numerical weather prediction model methods. All of these methods have limitations and there are great difficulties in verifying the forecasts, especially for low visibility cases. Monitoring visibility and providing data sets for verification is quite a challenge. Visibility can change rapidly within the traditional one hour reporting periods and it is necessary to know if precipitation is falling concurrently, at what rate and what type. If forecasts are based on relative humidity, there are significant problems in measuring that parameter near saturation conditions. Numerical weather prediction models also do not do an adequate job of forecasting relative humidity. Some illustrations from the Canadian experiences will be provided along with possibilities for future work.
Wednesday 30th April, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Google Scholar: track your citations and search for papers
Google Scholar is not only a valuable tool for finding others publications. It can also be used to keep track of your own publications and citations of them. This, in turn, can be used to assist in gathering information for input into job applications and internal publication databases.
In this seminar, Matt Wheeler will introduce some of the features of Google Scholar, followed by a demonstration of how to create a Google Scholar profile and link your existing publications to it. Having a profile enables Google Scholar to recommend papers to you, and making your profile accessible by the public increases your own exposure.
Friday 4th April, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Identifying East Coast Lows in reanalyses and models
BoM Climate Information Services / UNSW
East Coast Lows (ECLs) are strong low pressure systems that can cause severe weather and substantial rainfall along the east coast of Australia. Because of their importance, several databases of East Coast Lows have been developed in recent years, based on both manual identification of lows and objective tracking schemes that employ one or more reanalysis datasets.
In this talk I will discuss how sensitive the identification and characteristics of ECLs are to the choice of reanalysis dataset, spatial resolution of the pressure data, and the ECL identification method used. The ability of the WRF regional climate model to represent the seasonality and distribution of ECLs will also be briefly assessed, as well as its implications for future ECL studies as part of the NARCliM project.
Wednesday 2nd April, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
The Role of Soil Moisture and SSTs in Decadal Drought in Western North America
CIRES/ATOC, University of Colorado
Western North America is susceptible to severe impacts of decadal to multi-decadal droughts, as evidenced by treecore or lake sediment records. Future predictions suggest that this region will become more arid, with further consequences for water resources. Understanding the mechanisms of drought variability and persistence in western North America is critical for the eventual development of effective forecasting methods. The ocean is expected to be the main source of potential predictable decadal memory in the system as the atmosphere varies on a much shorter timescale. However, low frequency precipitation anomalies in western North America can occur in the absence of ocean feedbacks. Sea surface temperature anomalies in the north Pacific Ocean associated with around 20 per cent of the low frequency winter precipitation in California in the CMIP5 historical runs. This is not sufficient to use the skill of global coupled models in predicting ocean conditions ahead of time to successfully forecast the possibility of long-term drought in western North America. Megadroughts may be generated by unpredictable atmospheric noise, or persisted by other sources of low frequency variability such as land processes and feedbacks. Water storage and related variables which integrate precipitation are more predictable on longer timescales, as measured by anomaly correlation for hindcasts compared to a 'perfect model' control run with CESM1.0.3. The importance of SST anomalies or antecedent land conditions in initiating and persisting megadroughts in western North America is explored with ensemble simulations of CESM1.0.3, where the atmosphere is perturbed at the start and peak of megadroughts in the control run. The model results confirm the importance of internal variability, SST forcing and land processes in projections of future decadal hydroclimate; the relative role of each process differs for droughts with varying characteristics.
Friday 12th March, 10:00am - 11:00am, Conference/Meeting Rooms, 6th floor, 700 Collins St
Unified Model development: recent progress and future strategy
Director of Science, UK Met Office
Wednesday 12th March, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
An Assessment of Methods for Operational Mixing Height Determination; and the Southwest Monsoon and Fire Activity
Desert Research Institute, Nevada
Forecasts of mixed layer height are prepared for fire and smoke management such as prescribed burning, though smoke concentration and dispersion from wildfire is becoming increasingly important as related to public health. The nature of the primarily used Holzworth method and other mixed-layer determination techniques (e.g., Stull method) are principally based on the static stability structure of the atmosphere. However, their exclusion of the dynamic stability (e.g., wind shear) can lead to significant underestimation of the mixed-layer height. In the context of the operational forecasting, this study examines these techniques and compares computed heights to those derived from satellite-based lidar (from CALIPSO aerosol depth). Estimates are also examined against planetary boundary layer values from model-derived turbulent kinetic energy (TKE) the mean kinetic energy per unit mass associated with eddies in the turbulent flow, and a combined representation of static and dynamic stability. This presentation will describe these comparisons, and discuss a recommendation for a national standard methodology for operational mixing height determination in the U.S.
Friday 7th March, 2:00pm - 3:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Intraseasonal Predictability and Dynamical Processes: the MJO and NAO two-way global interaction
Deputy Director of Weather Science, UK Met Office
Wednesday 5th March, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
The Pilot National Heatwave Forecasting System
On 8 January 2014, the Bureau of Meteorology introduced a pilot national heatwave forecasting service. This seminar will describe the pilot forecasting service and the science behind it. While heatwave definitions have been used operationally in a small number of Australian locations (e.g., Adelaide), this new service represents the Bureau's first attempt at a national operational heatwave service. The service makes use of a concept called the Excess Heat Factor (EHF), developed by John Nairn in the Bureau's South Australian Regional Office. The EHF aims to capture the temperature signal relevant to human health outcomes. Future plans for the service and some preliminary verification results will be presented.
Friday 28th February, 2:00pm - 3:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Fast and slow response of sea ice and the Southern Ocean to ozone depletion
University of Washington
Interannual variability in the Southern Annular Mode (SAM) and sea ice covary such that an increase and southward shift in the surface westerlies coincides with an expansion of the sea ice cover, as seen in observations and models alike. Yet, the sea ice extent decreases in response to similar sustained wind anomalies driven by 20th century ozone depletion in modeling studies. Why does sea ice appear to have opposite responses to SAM-like variability on interannual and multi-decadal timescales? We demonstrate explicitly that the response of sea ice and the Southern Ocean to ozone depletion is a two timestep problem. The interannual variability of sea ice and the SAM parallels the fast response of sea ice to ozone depletion. The fast response is dominated by an enhanced northward Ekman drift, which transports heat northward and causes negative SST anomalies in summertime, earlier sea ice freeze-up, and increased sea ice concentrations and northward expansion of the sea ice edge year round. The enhanced northward Ekman drift causes a region of Ekman divergence south of the Antarctic polar front, which results in upwelling of warmer waters from below the mixed layer. With sustained westerly wind enhancement, the energy balance of the upper ocean is dominated by the upwelling heat flux from of the anomalous upwelling of warm waters over the northward heat flux from the anomalous Ekman drift. Hence, the slow response is positive SST in summertime and a reduction in the sea ice cover year round. We demonstrate this behavior in two models: one with an idealized geometry and another a sophisticated global climate model. We discuss the controls on the transitions of fast to slow response.
Wednesday 26th February, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Influence of Amplifying Rossby Waves on Tropical Cyclone Intensity, Structure and Rainfall
We re-visit the long-standing tropical cyclone-trough interaction problem and provide evidence that some storms experiencing significant changes in their behaviour, are influenced by direct interaction with amplifying, extratropical Rossby Waves. Back trajectories from the storm’s midlevels during these episodes, suggest that injection of environmental PV can influence vortex intensity, structure and rainfall. We illustrate the processes using case studies of: 1. Ex-TC Oswald, which produced extreme rain over Queensland, 2. Landfall of TC Fitow near Shanghai, where very heavy rain occurred 400km to the north of the centre, and 3. the much-studied Hurricane Opal, which underwent un-forecast and poorly-understood rapid intensification over the Gulf of Mexico just prior to landfall.
Monday 24th February, 11:00am - 12:15pm, Conference Room 3, 6th floor, 700 Collins St
UM status, plans & collaboration update
UK Met Office
This talk will cover Met office production; parallel suites from now to 2022; ENDGame; UM development and Rose; climate configs; global model evaluation and development; collaboration.
Friday 21st February, 12:00pm - 1:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Atmospheric dispersion and air quality research and services at the Met Office
UK Met Office
The Met Office deliver a range of dispersion and air quality services. In support of these, other policy questions and science challenges we conduct and collaborate in a wide ranging research program. This work focuses on developing and utilising the NAME (Offline Lagrangain model) and AQUM (Online configuration of the UM including suitable chemistry) models. During this talk I will describe the models and a number of the operational services and applications that they are applied to as well as the key role that collaboration plays in our success in both the services and research work. The talk will close with a brief look at our future plans and challenges.
Thursday 20th February, 2:30pm - 3:30pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Effects of declining aerosols in CMIP5 projections
All the Representative Concentration Pathways (RCPs) include declining aerosol emissions during the 21st century, but the effects of these declines on climate projections have had little attention. Whereas increasing aerosols have masked global warming in the past, projected declines in aerosol emissions are expected to accelerate global warming. However, the effects of declining aerosols on large-scale circulation may differ from those of increasing well-mixed greenhouse gases.
This talk will cover recent work that assesses the effects of declining anthropogenic aerosols in RCP4.5, and compares the effects with those of increasing well-mixed greenhouse gases. The analysis is partly based on “single-forcing” simulations with the CSIRO-Mk3.6 model, and is currently being extended to use a four-member multi-model ensemble. Topics to be addressed will include global and hemispheric changes in temperature and precipitation, midlatitude dynamics (including the southern annular mode) and the Hadley circulation.
Wednesday 19th February, 11:00am - 12:00pm, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Probabilistic prediction with deterministic models
University of Helsinki
Environmental management relies often on deterministic models and descriptions of the ecosystem to predict its response to management actions. However, from a practical management point of view the uncertainty in model predictions and the probability to achieve the targets are as essential as the point estimates provided by the deterministic models. In this talk I will present how to extend a deterministic model into a probabilistic form in order to assess the uncertainty in its predictions. As a case study I will consider a problem of predicting the probability to achieve the targets set by EU's Water Framework Directive (WFD) in Finnish coastal waters in the Gulf of Finland (GoF), one of the most eutrophicated areas of the Baltic Sea, under alternative management scenarios. Our approach combines the spatio‐temporal predictions of deterministic biogeochemical model with a Gaussian process to give a prior distribution for the spatio‐temporal function of nutrient concentrations and algal biomass. We use Bayes theorem and condition to large monitoring data set to calculate the posterior predictive distribution of the nutrient concentrations and algal biomass. This presentation will summarize the following work: Vanhatalo et al. (2013). Probabilistic Ecosystem Model for Predicting the Nutrient Concentrations in the Gulf of Finland under Diverse Management Actions. Environmental Science \& Technology, 47(1):334‐341.
Wednesday 19th February, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Representing tropical convection in weather and climate models - the need and opportunities for a revolution
ARC Centre of Excellence in Climate System Science, Monash University
The representation of convection in weather and climate models remains one of the most difficult tasks in contemporary model development. Many of the well-known model errors including the poor simulation of the tropical mean precipitation patterns as well as errors in the representation of major modes of tropical variability ranging from ENSO to the Madden-Julian Oscillation to the diurnal cycle of precipitation have been shown to be associated with flaws in the representation of convection. By necessity convection in climate models is represented by means of parametrization, which inherently relies on the exploitation of relationships between large and small scales in a convecting atmosphere.
Astonishingly, despite their clear shortcomings, contemporary parametrizations of convection still rely on paradigms developed in the 1970s and 1980s, including the existence of diagnostic and deterministic relationships between the "local" large-scale state of the atmosphere and the behaviour of an ensemble of convective clouds embedded in that state. We will exploit modern observations at Darwin, Northern Australia, to expose severe shortcomings in the decade-old paradigms currently in use. We will show that the common use of stability measures, such as CAPE, to determine the amount of convection in models is not supported by observations. We will demonstrate that much of the relationship between the large scales and convective rainfall is driven by the area that is precipitating. Finally we will apply our findings to the conceptual design of a new treatment of convection in large-scale models based on a prognostic and stochastic multi-scale cloud model.
Wednesday 12th February, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
The emerging IIOE-2, an exciting international scientific initiative five decades on from the original International Indian Ocean Expedition (IIOE) of the 1960s
A pioneering collaborative international scientific exercise to explore the Indian Ocean was undertaken under the auspices of SCOR and the IOC during 1959-65 - termed the International Indian Ocean Expedition (IIOE). It was a formative oceanographic program, including voyages of discovery, focusing the world’s ocean observing community on the Indian Ocean, uncovering scientific data of significant societal and environmental relevance, as well as catalysing the establishment of new marine institutions and forward interest in the ocean science of the basin.
The Indian Ocean and wider global oceanic community is planning now to revisit the Indian Ocean, in a major scientific undertaking, timed to coincide with the 50th anniversary of IIOE, again involving expeditions in the form of cruises but this time also with a range of significant complementary activities (see the IIOE-2 portal on www.iocperth.org).
The IIOE-2 planning phase is underway (2013-2014), co-chaired by IOC PPO and so far involving a suite of actions. Two IIOE-2 Reference Group meetings have taken place in 2013 (Hyderabad and Qingdao), including a team of international scientists, managers and officials. An IIOE-2 ‘science and implementation plan’ (incl. business case and budget) will be formulated and submitted to the IOC in mid-2014 to help motivate and underpin the planned implementation phase (2015-2020).
It is envisaged that IIOE-2 will comprise voyages of discovery, and encompass related scientific research, applications, training/capacity building, outreach and awareness themes and more. It will provide new information with relevancies to all Indian Ocean rim and island countries, as well as to the globe in general.
The seminar provides an opportunity for BoM stake-holders to (i) be briefed, (ii) identify linkages and (iii) consider engagement in this exciting IIOE-2 initiative.
Background IIOE and IIOE-2;
Reference Group meetings;
Towards an IIOE-2 science and implementation plan;
Plenary discussion - Australian stakeholder engagement and national approach to IIOE-2 engagement.
Wednesday 5th February, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Is there a causal link between moistening preceding deep convection and cumulus congestus clouds?
Monash University / CAWCR
Some cumulus clouds with tops between 3 and 7 km (Cu3km-7km) remain in this height region throughout their lifetime (congestus) while others develop into deeper clouds (cumulonimbus). Here we describe a technique to identify the congestus and cumulonimbus cloud types using data from scanning weather radar and identify the atmospheric conditions that regulate these two modes. A two-wet season cumulus cloud database of the Darwin C-band polarimetric radar is analysed and the two modes are identified by examining the 0 dBZ cloud top height (CTH) of the Cu3km-7km cells over a sequence of radar scans. It is found that ~26% of the classified Cu3km-7km population grow into cumulonimbus clouds. The cumulonimbus cells exhibit reflectivities, rain rates and drop sizes larger than the congestus cells. The occurrence frequency of cumulonimbus cells peak in the afternoon, at ~1500 local time, a few hours after the peak in congestus cells. The analysis of Darwin Airport radiosonde profiles associated with the two types of cells shows no noticeable difference in the thermal stability rates, but a significant difference in mid-tropospheric (510 km) relative humidity. We find moister conditions in the hours preceding the cumulonimbus cells when compared with the congestus cells. Using a moisture budget data set derived for the Darwin region, it is shown that the existence of cumulonimbus cells, and hence deep convection, is mainly determined by the presence of the mid-troposphere large-scale upward motion and not merely by the presence of congestus clouds prior to deep convection. This contradicts the thermodynamic viewpoint that the mid-troposphere moistening prior to deep convection is solely due to the preceding cumulus congestus cells.
Wednesday 22nd January, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Climate Impact of the Antarctic ozone hole: long-term trend and inter-annual variability
School of Earth and Environmental Sciences, Seoul National University
The impact of stratospheric ozone on the tropospheric general circulation of the
Southern Hemisphere (SH) is examined with observations, chemistry‐climate models participating in the Chemistry‐Climate Model Validation project phase 2 (CCMVal‐2), and coupled models from the Coupled Model Inter comparison Project phase 3 and 5 (CMIP3 and CMIP5). Model integrations of both the past and future climates reveal the crucial role of stratospheric ozone in driving SH circulation change: stronger ozone depletion in late spring generally leads to positive trend in SAM index in austral summer, resulting in poleward displacement of midlatitude jet and poleward widening of the Hadley cell. These changes are comparable to or even larger than those associated with greenhouse gas increase. In particular, it is found that inter-model spread of future projection of SAM index is largely explained by uncertainty in Antarctic stratospheric temperature change.
Using observations, it is further shown that Antarctic ozone hole has affected not only the long-term climate change but also the inter-annual variability of SH surface climate. A significant negative correlation is observed between September ozone concentration and the October SAM index, resulting in systematic variations in precipitation and surface air temperature throughout the SH. This time-lagged relationship is comparable to and independent of that associated with El Niño-Southern Oscillation and the Indian Ocean Dipole Mode, suggesting that SH seasonal forecasts could be improved by considering Antarctic stratospheric variability
Monday 20th January, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St
Findings from sustained observations off northern Chile - the long (trends) and the short (diurnal)
Woods Hole Oceanographic Institution
Since October 2000, a well-instrumented surface mooring has been maintained some 1,500 km west of
the coast of northern Chile, roughly in the location of the climatological maximum in marine stratus clouds. The first
nine years of the data have been carefully and consistently quality controlled. Statistically significant increases in
wind stress and decreases in annual net air-sea heat flux and in latent heat flux have been observed. If the increased
oceanic heat loss continues, the region will within the next decade change from one of net annual heat gain by the
ocean to one of neat annual heat loss. Already, annual evaporation of about 1.5 m of sea water a year acts to make
the warm, salty surface layer more dense. Of interest is examing whether or not increased oceanic heat loss has the
potential to change the structure of the upper ocean and potetnially remove the shallow warm, salty mixed layer that now
buffers the atmosphere from the interior ocean. Insights into how that warm, shallow layer is formed and maintained
come from looking at oceanic response to the atmosphere at diurnal tie scales. Restratification each spring and summer
is found to depend upon the occurrence of events in which the trade winds decay, allowing diurnal warming in the
near-surface ocean to occur, and when the winds return resulting in a net upward step in sea surface temperature.
This process is proving hard to accurately model.
A PDF copy of all the presented seminars can be found at the "Find Seminar Presentation Documents..." link at the top of the page (available to BoM staff only). Seminars for previous years can be found at the "Goto list of BMRC seminars for ..." site at the top of the page. In addition, a list of actual videos from some previous seminars is held in the library and can be found on the
catalogue by entering Series: BMRC,
Format: Video. If you would like to have a talk videotaped please contact the
seminar coordinator. Note: as of 2005, it is standard practice for all seminars to be recorded as wmv movies,
with the permission of the presenter.
If you would like to know more details of coordinating seminars (if, for example,
you are hosting a visitor who will be giving a seminar and the regular seminar coordinator is not available),
have a look at the document, "Instructions for CAWCR Seminar Coordinator"