Seminars - Melbourne

To receive notification of upcoming CAWCR seminars, please send an email request with the subject line 'subscribe cawcr seminars' to: CAWCR_Seminars_Admin -at- cawcr.gov.au. Similarly, to unsubscribe replace subject line with 'unsubscribe cawcr seminars'.

To schedule a CAWCR seminar, contact the seminar coordinators with the details and the proposed date.

Here are details of how to access the shared calendar in Outlook (internal use only) to view available seminar time slots.


CAWCR SEMINARS 2014

Date Time Title Speaker Affiliation
Wednesday 10th September 10:00AM TBA Eric Maloney Colorado State University
Wednesday 3rd September 10:00AM TBA Eunpa Lim CAWCR BoM
Wednesday 20th August 10:00AM A close shave with Occam's razor: managing complexity in a radar rainfall estimation system Alan Seed CAWCR BoM
Wednesday 13th August 10:00AM Self-energy stochastic subgrid modelling in simulations of quasi-geostrophic and boundary layer flows Vassili Kitsios Monash University / CSIRO
Monday 11th August 10:30AM TBA Shawn Smith Center for Ocean-Atmospheric Prediction Studies, FSU
Wednesday 6th August 10:00AM On the application of STEPS2 over Australia: Seamless Rainfall Forecasting Shaun Cooper CAWCR BoM
Thursday 24th July 2:00PM Cumulus clouds above Dominica and their response to cloud-layer humidity variations Campbell Watson Yale University
Monday 21st July 3:15PM An overview of the Centre for Climate Research Singapore: Our strategy and research plans Chris Gordon Centre for Climate Research Singapore
Wednesday 16th July 10:00AM New Storm Tide Decision Support Products for use in Emergency Management, Queensland Joanna Burston Griffith Centre for Coastal Management, Griffith University
Wednesday 2nd July 10:00AM NexGen project: Past, present and future - a CAWCR team perspective Gary Weymouth CAWCR BoM
Friday 27th June 2:00PM Cloud products development for Himawari-8/9 Toshi Kurino Meteorological Satellite Center, JMA
Wednesday 25th June 10:00AM Tropical cyclone intensity and surface wind structure estimation and formation detection using the Deviation Angle Variance Technique Liz Ritchie University of Arizona
Tuesday 17th June 10:30AM Wave-induced Boundary-Layer Separation and Atmospheric Rotors Vanda Grubišić EOL NCAR
Thursday 12th June 10:00AM CMIP6 - Experimental design proposal and invitation for feedback Tony Hirst CAWCR CSIRO
Tuesday 10th June 2:30PM ENSO-AIR: The atmospheric dynamics of ENSO Dietmar Dommenget ARC Centre of Excellence in Climate System Science, Monash University
Wednesday 28th May 10:00AM Overview of the perspective algorithms for signal processing, calibration, and data analysis for operational dual-polarization weather radars Alexander Ryzhkov University of Oklahoma and National Severe Storms Laboratory
Monday 26th May 9:30AM Future projection of ocean wave climate based on Japanese MRI-AGCM3.2 ensemble experiments Tomoya Shimura Kyoto University, Japan
Friday 23rd May 2:30PM On the rates of record setting in Australian monthly and seasonal temperature time series Robert Fawcett CAWCR BoM
Friday 9th May 10:00AM Earth System Modelling for Climate Change R. Krishnan Indian Institute of Tropical Meteorology
Wednesday 7th May 10:00AM Advances in ocean forecasting - outcomes from the BLUElink-3 project Peter Oke and Gary Brassington CAWCR, OOAP
Monday 5th May 3:30PM Monitoring and Forecasting Visibility in Canada George Isaac Weather Impacts Technology Incorporated
Wednesday 30th April 10:00AM Google Scholar: track your citations and search for papers Matt Wheeler CAWCR BoM
Friday 4th April 10:00AM Identifying East Coast Lows in reanalyses and models Acacia Pepler BoM Climate Information Services / UNSW
Wednesday 2nd April 10:00AM The Role of Soil Moisture and SSTs in Decadal Drought in Western North America Sally Langford CIRES/ATOC, University of Colorado
Friday 14th March 10:00AM Unified Model development: recent progress and future strategy Andy Brown Director of Science, UK Met Office
Wednesday 12th March 10:00AM An Assessment of Methods for Operational Mixing Height Determination; and the Southwest Monsoon and Fire Activity Tim Brown Desert Research Institute, Nevada
Friday 7th March 2:00PM Intraseasonal Predictability and Dynamical Processes: the MJO and NAO two-way global interaction Gilbert Brunet Deputy Director of Weather Science, UK Met Office
Wednesday 5th March 10:00AM The Pilot National Heatwave Forecasting System Robert Fawcett CAWCR BoM
Friday 28th February 2:00PM Fast and slow response of sea ice and the Southern Ocean to ozone depletion Cecilia Bitz University of Washington
Wednesday 26th February 10:00AM Influence of Amplifying Rossby Waves on Tropical Cyclone Intensity, Structure and Rainfall Noel Davidson CAWCR BoM
Monday 24th February 11:00AM UM status, plans & collaboration update George Pankiewicz UK Met Office
Friday 21st February 12:00PM Atmospheric dispersion and air quality research and services at the Met Office Matt Hort UK Met Office
Thursday 20th February 2:30PM Effects of declining aerosols in CMIP5 projections Leon Rotstayn CAWCR CSIRO
Wednesday 19th February 11:00AM Probabilistic prediction with deterministic models Jarno Vanhatalo University of Helsinki
Wednesday 19th February 10:00AM Representing tropical convection in weather and climate models - the need and opportunities for a revolution Christian Jakob ARC Centre of Excellence in Climate System Science, Monash University
Wednesday 12th February 10:00AM The emerging IIOE-2, an exciting international scientific initiative five decades on from the original International Indian Ocean Expedition (IIOE) of the 1960s Nick D'Adamo IOC Perth
Wednesday 5th February 10:00AM Is there a causal link between moistening preceding deep convection and cumulus congestus clouds? Vickal Kumar Monash University / CAWCR
Wednesday 22nd January 10:00AM Climate Impact of the Antarctic ozone hole: long-term trend and inter-annual variability Seok-Woo Son School of Earth and Environmental Sciences, Seoul National University
Monday 20th January 10:00AM Findings from sustained observations off northern Chile - the long (trends) and the short (diurnal) Bob Weller 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 seminar coordinators



ABSTRACTS



Wednesday 10th September, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St

TBA

Eric Maloney
Colorado State University

TBA



Wednesday 3rd September, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St

TBA

Eunpa Lim
CAWCR BoM

TBA



Wednesday 20th Augusst, 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

Alan Seed
CAWCR BoM

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

Vassili Kitsios
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

TBA

Shawn Smith
Center for Ocean-Atmospheric Prediction Studies, FSU

TBA



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

Shaun Cooper
CAWCR BoM

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.



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

Campbell Watson
Yale University

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

Chris Gordon
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

Joanna Burston
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

Gary Weymouth
CAWCR BoM

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

Toshi Kurino
Meteorological Satellite Center, JMA

No Abstract.



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

Liz Ritchie
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

Vanda Grubišić
EOL NCAR

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

Tony Hirst
CAWCR CSIRO

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.

Useful sites: 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

Dietmar Dommenget
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

Alexander Ryzhkov
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

Tomoya Shimura
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

Robert Fawcett
CAWCR BoM

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

R. Krishnan
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
CAWCR, OOAP

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

George Isaac
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

Matt Wheeler
CAWCR BoM

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

Acacia Pepler
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

Sally Langford
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

Andy Brown
Director of Science, UK Met Office

No abstract.



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

Tim Brown
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

Gilbert Brunet
Deputy Director of Weather Science, UK Met Office

No abstract.



Wednesday 5th March, 10:00am - 11:00am, Conference/Meeting Rooms, 9th floor east, 700 Collins St

The Pilot National Heatwave Forecasting System

Robert Fawcett
CAWCR BoM

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

Cecilia Bitz
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

Noel Davidson
CAWCR BoM

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

George Pankiewicz
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

Matt Hort
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

Leon Rotstayn
CAWCR CSIRO

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

Jarno Vanhatalo
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

Christian Jakob
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

Nick D'Adamo
IOC Perth

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.

Presentation structure: Background IIOE and IIOE-2; Reference Group meetings; Towards an IIOE-2 science and implementation plan; Governance; 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?

Vickal Kumar
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

Seok-Woo Son
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)

Bob Weller
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"

Please note that the Disclaimers for the Bureau of Meteorology and CSIRO apply also to this site.
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