| Date |
Time |
Title |
Speaker |
Affiliation |
| Mon 7 January 2008 |
2.00pm |
Soil moisture products: satellite / model / in situ cross-validation |
Jean-Christophe Calvet, Christoph Rüdiger, Noureddine Fritz, Jean-François Mahfouf |
Météo France/CNRM |
| Tue 8 January 2008 |
10.00am |
Monitoring water stress using time series of observed to unstressed surface temperature difference |
Gilles Boulet |
Cesbio |
| Tue 8 January 2008 |
2.00pm |
Soil moisture analyses for NWP applications: Data assimilation experiments with ECMWF's Integrated Forecast System
|
M. Drusch, E. Andersson, G. Balsamo, P. de Rosnay, and K. Scipal |
ECMWF |
| Tue 8 January 2008 |
2.30pm |
Global Hydrology in NWP: combining atmospheric water closure with river discharge to validate land surface parametrizations |
G. Balsamo, A. Beljaars, P. Viterbo, M. Hirschi, B. van den Hurk, A. K. Betts |
ECMWF |
| Wed 16 January 2008 |
10.00am |
ACCESS Meeting: Overview
|
Dr. Kamal Puri |
CAWCR BoM |
| Wed 16 January 2008 |
10.30am |
ACCESS Meeting: Atmospheric Modelling Team
|
Dr. Gary Dietachmayer |
CAWCR BoM |
| Wed 16 January 2008 |
11.00am |
ACCESS Meeting: Atmospheric Data Assimilation
|
Dr. Peter Steinle |
CAWCR BoM |
| Wed 16 January 2008 |
11.30am |
ACCESS Meeting: Ocean & Coupled Modelling
|
Dr. Tony Hirst |
CAWCR CSIRO |
| Wed 16 January 2008 |
2.00pm |
ACCESS Meeting: Ocean Carbon Modelling
|
Dr. Richard Matear |
CAWCR CSIRO |
| Wed 16 January 2008 |
2.30pm |
ACCESS Meeting: Model Evaluation
|
Dr. Laurie Rikus |
CAWCR BoM |
| Wed 16 January 2008 |
3.00pm |
ACCESS Meeting: Land Surface and Carbon Cycle Modelling
|
Dr. Yingping Wang |
CAWCR CSIRO |
| Fri 18 January 2008 |
10.00am |
Impacts of land management on water quality and quantity |
Dr. Bethanna Jackson |
Department of Civil and Environmental Engineering, Imperial College London |
| Fri 15 Febuary 2008 |
11.30am |
Hedging the Weather needs an Intelligent Market |
R. Smart |
Wollongong University |
| Wed 27 Febuary 2008 |
10.00am |
Synoptic and intra-seasonal variability of convection and rainfall over the Southern African region and scale-interactions |
N. Fauchereau |
University of Cape Town |
| Wed 5 March 2008 |
10.00am |
Connections between ozone and climate |
Eugene Cordero |
San Jose State University |
| Thur 13 March 2008 |
10.00am |
Diagnosing the health of your variational assimilation system. Part I: in Observation Space |
Chermelle Engel |
CAWCR |
| Wed 19 March 2008 |
10.00am |
The dynamics of heat lows |
Roger Smith |
University of Munich |
| Thur 20 March 2008 |
10.00am |
Interactions of tropical waves and diabatic vortices in tropical cyclone formation |
Michael Montgomery |
Naval Postgraduate School, Monterey |
| Wed 2 April 2008 |
10.00am |
GIFS/ TIGGE - An ensemble of NWP ensembles for predicting high impact weather worldwide |
Beth Ebert |
CAWCR BoM |
| Wed 9 April 2008 |
10.00am |
Diagnosing the health of your variational assimilation system. Part II: in Model Space |
Chermelle Engel |
CAWCR |
| Thur 10 April 2008 |
10.00am |
Oxygen declines in the interior waters of the Subarctic Pacific |
Frank Whitney |
Institute of Ocean Sciences, Sidney, BC, Canada |
| Wed 16 April 2008 |
10.00am |
The Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative |
Rob Allen |
Hadley Centre, UK Met Office |
| Mon 21 April 2008 |
11.00am |
New approaches to flood forecasting |
Ezio Todini |
Dept. of Earth and Geo-Environmental Sciences - University of Bologna |
| Wed 07 May 2008 |
10.00am |
Climate Change and Probable Maximum Precipitation |
Rob Smalley |
CAWCR BoM |
| Mon 12 May 2008 |
11.00am |
Progress towards operational implementation of enhanced vertical resolution in the Met Office Unified Model |
Stuart Webster |
Hadley Centre, UK Met Office |
| Wed 14 May 2008 |
10.00am |
The east Australian pressure gradient index (GDI) |
Clinton Rakich |
BoM NSWRO |
| Fri 23 May 2008 |
10.00am |
Operational Tsunami Prediction and Assessment System (OTPAS) |
HengKek Choo |
National University of Singapore |
| Wed 28 May 2008 |
10.00am |
A New Paradigm for Radar Sensing of the Atmosphere: An Overview of the CASA Project |
Frederick H. Carr |
University of Oklahoma |
| Wed 28 May 2008 |
12.00pm |
Understanding Subsurface ENSO Dynamics for Improving Model Analysis |
Jaclyn Brown |
CAWCR CMAR |
| Wed 18 Jun 2008 |
10.00am |
Tropical cyclones, climatic variation and economics in the Caribbean
|
Soloman Hsiang |
Columbia University |
| Wed 20 Aug 2008 |
10.00am |
Ozone
|
Lilia Deschamps |
CAWCR BoM |
The venue is the BMRC seminar room (Floor 9, east side).
Until further notice, seminars are at 10 am on Wednesdays with duration
of 30 to 50 minutes + questions. Dates and times are shown. If you are a vistor to the Bureau, you need to register at reception in the foyer.
Emphasis is on work in progress. Partly because of this, the schedule is
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A list of all the presented seminars can be found at the "Entire list of presented BMRC seminars for 2007" site at the top of the page. This site also lists whether, provided the presenter has agreed, a copy of the powerpoint (or pdf) presentation
documents, as well as a wmv movie of the talk, can be found on the "Seminar Presentation Documents" site listed at the
top of the page. If we have them, then these are indicated by a powerpoint (or pdf) icon next to the seminar date, or
a movie-camera icon next to the seminar time. Seminars for previous years can be found at the "Goto list of BMRC
seminars for 2006" 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,
provided the presenter agrees.
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 BMRC Seminar Coordinator"
For further details contact the seminar coordinator,
Terry O'Kane, on 03 9669 4429, t.okane@bom.gov.au
ABSTRACTS
Monday 7 January, 2pm-3pm, BMRC Seminar Room, 9th floor east, 700 Collins St
Soil moisture products: satellite / model / in situ cross-validation
Jean-Christophe Calvet, Christoph Rüdiger, Noureddine Fritz, Jean-François Mahfouf
Météo France/CNRM
Abstract:
Land biophysical variables can be monitored from space (e.g. near-surface soil moisture by using microwave techniques). The same variables can be simulated by land surface models. Soil moisture can be measured in situ by using automatic probes. The comparison of these data permits to understand the biophysical processes and improve their modelling.
The SMOS mission (http://www.cesbio.ups-tlse.fr/us/indexsmos.html) will provide from space estimates of the near-surface soil moisture. CNRM intends to implement the assimilation of the SMOS data at a global scale in the ARPEGE model in order to assess their added value for numerical weather forecast, and at the regional scale for hydrometeorological applications over France (the SIM model). Active microwave products can be used in synergy with SMOS. The potential of C-band wind-speed scatterometers has been shown over southwestern France by Pellarin et al. 2006. These sensors present the same spatial resolution as SMOS, and ASCAT on METOP (an operational meteorological satellite) will permit EUMETSAT to issue global soil moisture products with a sampling time similar to SMOS (http://www.eumetsat.int/eps_webcast/eps_en/print.htm). Moreover, new high or medium resolution radars (ENVISAT/ASAR, ALOS/PALSAR, RADARSAT-2, etc) may help implement spatial disaggregation techniques (Zribi et al. 2007).
SMOSMANIA (2007-2013) is a project aiming at implementing soil moisture measurements in a portion of the automatic ground station network of Météo-France (the RADOME network). The SMOSMANIA network will permit to monitor soil moisture in southwestern France thanks to in situ automatic, real-time measurements of soil moisture profiles (-5, -10, -20, -30 cm). Twelve ground stations were activated in 2006 forming a Mediterranean-Atlantic gradient.
The introduction of carbon cycle modelisation into the operational model platform SURFEX (option ISBA-A-gs, Calvet et al. 1998-2007, Gibelin et al. 2006) allows the simulation of the leaf area index. By means of a comparison with existing LAI satellite products (from MODIS, SPOT/VGT), the modelled LAI may be validated or its shortcomings identified.
Moreover, the above-ground biomass of crops can now be simulated and compared to the statistics of the agricultural yield each year. This is presented with case study undertaken for south-western France.
Tuesday 8 January, 10am-11am, BMRC Seminar Room, 9th floor east, 700 Collins St
Monitoring water stress using time series of observed to unstressed surface temperature difference
Gilles Boulet
Cesbio
Abstract:
Remote sensing data in the thermal infra red (TIR) part of the spectrum provides indirect estimates of water stress - defined as a function of the ratio between actual and potential evaporation rates - at the earth surface. During the first stage of evaporation ('energy limited' evaporation), this ratio is close to one. During the second stage of evaporation ('soil controlled' evaporation) water stress occurs and as a result this ratio drops below one. Recently, methods using TIR data to monitor stress have shifted from establishing empirical relationships between combined vegetation cover/temperature indices and soil moisture status to data assimilation of surface temperature into complex soil-vegetation-atmosphere transfer models. However, data and expertise are often lacking to widely apply those methods. In this paper we investigate the proof-of-concept of using solely the difference between actual and unstressed surface temperature as a baseline to monitor water stress. The unstressed temperature is the equilibrium temperature of a given surface expressed in potential conditions, computed with an energy balance model. Theoretical, modelling, and experimental documentation of the proof-of-concept are shown for datasets acquired within the frame of two international experiments in semi-arid region. We show that the difference between the observed and the unstressed surface temperatures is almost linearly related to water stress. A sensitivity study is carried out to test the impact of modelling errors on the evaluation of the unstressed temperature. We found that even with inaccurate but realistic values of the surface parameters used to solve the energy balance and compute the unstressed temperature, the observed to unstressed surface temperature difference is still more relevant to detect second-stage processes than the difference between the observed surface temperature and the air temperature. The perspective of using an empirical index based on this difference is also investigated. These results are especially attractive for application based on TIR satellite imagery at a regional scale.
Tuesday 8 January, 2.00pm-2.30pm, BMRC Seminar Room, 9th floor east, 700 Collins St
Soil moisture analyses for NWP applications: Data assimilation experiments with ECMWF's Integrated Forecast System
M. Drusch, E. Andersson, G. Balsamo, P. de Rosnay, and K. Scipal
ECMWF
Abstract:
Operational soil moisture analyses are often based on observed screen-level parameters.
Since 2 m temperature and relative humidity are only indirectly related to the water content of the root zone the analyses tend to improve the turbulent fluxes and consequently the weather forecast. However, the analysed soil moisture is often not more accurate than the first guess. Satellite observations from ASCAT and the future SMOS mission provide direct information on surface soil moisture and constrain the soil moisture analysis.
The presentation introduces the current operational optimal interpolation scheme and shows it's impact on the forecast. Results from research experiments using satellite observations are presented and the future ECMWF land surface analysis system is described.
Tuesday 8 January, 2.30pm-3pm, BMRC Seminar Room, 9th floor east, 700 Collins St
Global Hydrology in NWP: combining atmospheric water closure with river discharge to validate land surface parametrizations
G. Balsamo, A. Beljaars, P. Viterbo, M. Hirschi, B. van den Hurk, A. K. Betts
ECMWF
Abstract:
The primary focus for land surface schemes in NWP is to provide accurate energy and water fluxes at the surface along the forecast range. Land surface initialization for snow and soil moisture may itself concur to achieve this target for the deterministic forecast range (e.g. 10-day), often much shorter than the typical time-scale for hydrological changes.
However, the possibility of performing an accurate analysis are intrinsically related to the quality of the modeled snow and soil moisture, and most of all the correct timing of major land water movements (from snow-pack to soil and from soil to atmosphere and to rivers) may result of key importance, especially in areas where snow and soil moisture analyses have little chance to add information (e.g. due to the lack of usable observations).
For this reason at ECMWF effort is devoted to the improvement of soil and snow hydrology well beyond the medium-range (10-day to 10-year range).
The main tools will be illustrated and experimental results with a new hydrology (H-TESSEL) in long integrations will be presented together with examples from the ECMWF Reanalyses (ERA-40, ERA-Interim).
Wednsday 16 January, 10.00am-4.00pm, BMRC Seminar Room, 9th floor east, 700 Collins St
ACCESS Meeting
K. Puri, G. Dietachmayer, P. Steinle, T. Hirst, R. Matear, L. Rikus, Y. Wang, M. Naughton
CAWCR
Abstract:
Summary and discussion of progress in ACCESS to date.
Friday 18 January, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
Impacts of land management on water quality and quantity
Bethanna Jackson
Imperial College London
Abstract:
Farmers and other rural land managers are facing increasing demands to ensure land is managed in a sustainable manner. Issues that must be considered include biodiversity, flood risk, diffuse and point-source pollution, social, environmental and economic sustainability and climate change impacts. However, understanding and predicting the impacts of land management is a fundamental research challenge. Experimental and modelling studies of the link between land use management change and various sustainability criteria are mostly small-scale; the few concerned with large scale impacts have very limited data support. There are also major problems of interpretation due to landscape heterogeneity. Results from recent research quantifying impacts of land use management at the hillslope scale, and developing new modelling strategies to generate meaningful predictions at catchment scale are presented. Comprehensive plot and field scale data are used to inform development and parameterisation of detailed models of water flow and nutrient transport. Results, in combination with information from catchment scale data and up-scaling techniques, are used to formulate appropriate representations at larger scales. Illustrative results are presented for two case studies from the UK. In the first, the potential of localised strategic land use changes for reduction of flood risk is demonstrated using data from a predominately grazed clay catchment in Wales. In the second, impacts of changes to agricultural practice on nitrogen levels in permeable catchments with long residence times are examined. Results from a lowland Chalk catchment in England suggest that even under stringent controls, the effects of historical fertiliser loading will prevent control of nutrient levels being achieved within the timelines demanded by incoming European legislation.
Friday 15 Febuary, 11.30am, BMRC Seminar Room, 9th floor east, 700 Collins St
Hedging the Weather needs an Intelligent Market
Robert Smart
Centre for Computer and Information Security Research, University of Wollongong
Abstract:
The Bureau of Meteorology plans to install radar systems more widely.
Combined with other sources of information this will allow the Bureau to give an unbiased and reasonably accurate report of how much rain has fallen and where. This can form the basis of an insurance system to allow farmers and others to hedge against the weather. It could be done in a simple and old fashioned way, or we could do it properly by building an Intelligent Market. This talk will explain how such an Intelligent Market would operate and its advantages. Such a market would, in turn, create a significant demand for climate and weather expertise and technology. There are exciting prospects for other Intelligent Markets which would naturally interact with the Rainfall Hedge market.
Wednesday 27 Febuary, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
Synoptic and intra-seasonal variability of convection and rainfall over the Southern African region and scale-interactions
Nicolas Fauchereau
Oceanography Department, University of Cape-Town, South Africa
Abstract:
The interannual variability of rainfall and convection over Southern Africa is relatively well-known and has been related for example to the ENSO phenomenon; El Nino (La Nina) being often associated with below (above) normal cumulative rainfall during the Southern hemisphere summer.
However, uncertainties remain on the origin of non-linearities of the ENSO impact on the region, and more generally the characteristics of subseasonal (synoptic to intra-seasonal) variability of rainfall and convection and its interaction with the interannual timescales are not known.
In this presentation we will give an overview of our latest studies on these topics:
1)We have shown (Fauchereau et al., 2007) that the daily convective activity over Southern Africa can be statistically separated in a limited number of recurrent regimes that significantly impact the sub-seasonal rainfall variability over South Africa. Amongst these regimes are 3 indicative of strong tropical-temperate interactions. Their probability of occurrence is significantly modified during El Nino and La Nina years. This study provides the link between the interannual, near-global variability and the daily, synoptic anomalies over South Africa.
2)At a longer time-scale (Pohl et al., 2007) we have shown that the major oscillatory mode in the tropical Atmosphere at the 20-70 days time-scale, namely the Madden-Julian Oscillation (MJO), impacts significantly on the convection and rainfall field in South Africa, with wet and dry spells within the summer rain region of South Africa being related to specific phases of the life-cycle of the oscillation.
3)A latest study focuses on the time-scale interactions between the Tropical Temperate Troughs on one hand, shown to operate at the synoptic (1 10 days approx.) range, and the Madden Julian Oscillation on the other hand. It shows that these two modes of subseasonal variability do not seem to interact and are statistically independent. Consistently with previous analyses, El Nino (La Nina) years are seen to be associated with dry (wet) conditions over Southern Africa. At the subseasonal timescale, ENSO is seen to impact both on the mean intensity of the atmospheric convection, and on the number of convective days.
references:
N. Fauchereau, B. Pohl, C.J.C. Reason, M. Rouault and Y. Richard, 2007: Recurrent daily OLR patterns in the Southern Africa / Southwest Indian Ocean region, implications for South African rainfall and teleconnections. Submitted to Climate Dynamics, October 2007. CLIDY-D-07-00178
B. Pohl, N. Fauchereau, C.J.C. Reason and M. Rouault, 2007: Relationships between the Antarctic Oscillation, the Madden-Julian Oscillation and ENSO, and consequences for rainfall analysis. submitted to Journal of Climate.
B. Pohl, N. Fauchereau, Y. Richard, M. Rouault and C.J.C. Reason, 2007: Convective Variability Timescales in Southern Africa: on the role of the tropical-temperate interactions, the MJO and ENSO. submitted to Climate Dynamics. December 2007. CLIDY-D-07-00213
Wednesday 5 March, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
Connections between ozone and climate
Eugene Cordero
San Jose State University
Abstract:
Ozone plays an important role in shaping the climate of the stratosphere. While variations in ozone over the last few decades produce a discernable impact on the climate of the stratosphere, how these changes impact the troposphere is less well understood. In this talk, both climate model simulations and theoretical considerations are used to explore the role ozone plays on contemporary climate change. Simulations from coupled chemistry-climate models (CCMs) used for the 2006 WMO/UNEP Ozone Assessment and atmosphere ocean general circulation models (AOGCM) used for the 2007 IPCC Fourth Assessment Report are analyzed to evaluate how ozone changes affect temperature trends in the upper troposphere and lower stratosphere during the 20th century. In addition to direct changes in radiation due to changes in mean ozone, ozone can also affect the dynamics of large scale waves though wave induced heating perturbations. Using theoretical and mechanistic models, the role of wave-induced ozone heating is explored and applied to changes in ozone due to the solar cycle and ozone depletion.
Thursday 13 March, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
Diagnosing the health of your variational assimilation system. Part I: in Observation Space
Chermelle Engel
CAWCR
Abstract:
Data assimilation is an important part of the numerical weather prediction process.
This talk will try to address:
- why data assimilation is so complex,
- the difference between observation and model space and,
- the possibility of assessing the accuracy of variational data assimilation system parameters using statistics in observation space.
This talk is the first in a two-part series. The second part will address diagnosing the health of a variational assimilation system using statistics in model space.
Wednesday 19 March, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
The dynamics of heat lows
Roger K Smith
University of Munich
Abstract:
I will discuss some insights obtained from recent numerical model simulations of a heat low in an idealized flow configuration. The calculations were performed by my former student in Munich, Thomas Spengler, now at ETH in Zurich, Switzerland. Tthe heat low has a minimum surface pressure in the early evening following strong solar heating of the land, but the low-level cyclonic circulation is strongest in the just before sunrise following a prolonged period of low-level convergence. Thus the heat low is not approximately in quasi-geostrophic or gradient wind balance. The low-level convergence is associated with the sea-breeze and later with the nocturnal low-level jet. The heat low is surmounted by an upper-level anticyclone, which is largely in gradient wind balance and has a comparatively weak diurnal variation. I will discuss effects of differing land area on the heat low and on the anticyclone. In some respects there are analogies with the structure of tropical cyclones.
The processes associated with the flow evolution in the model, especially the deep convective mixing over land during the daytime and the development of a convergent nocturnal low-level jet, appear to be fundamental to understanding a range of low-level atmospheric phenomena over the arid interior of Australia. These include the diurnal behaviour of dry cold fronts and the generation of nocturnal wind surges and bores. There is now evidence that similar processes operate in other arid regions of the world (e.g. over North Africa), where deep convective mixing over land produces anomalies of diabatic heating in the lower atmosphere. Our calculations suggest that the heat low over Australia may be important to understanding the summer monsoon.
Thursday 20 March, 10.00am, BMRC Seminar Room, Level 6 Conference Room, 700 Collins St
Interactions of tropical waves and diabatic vortices in tropical cyclone
Michael Montgomery
Naval Postgraduate School, Monterey, USA
Abstract:
Tropical cyclone (TC) formation is generally divided into two components: (1) the establishment of a large-scale favourable environment and (2) the construction of a TC-scale vortex within that environment. The role of tropical waves in providing enhanced cyclonic vorticity and areas of preferred convection (step 1), and the role of deep convection in concentrating vorticity into the TC-scale (Step 2) are both well recognised and have been for some time. Despite this established understanding the question of whether or not any individual system will develop is still a big unknown.
In this presentation Mike Montgomery will propose a new link between steps 1 and 2 that offers important insight into TC formation dynamics and will likely shed light onto the mystery of whether or not any particular disturbance becomes a tropical cyclone.
Wednesday 2 April, 10.00am, BMRC Seminar Room, Level 9th floor ea
st, 700 Collins St
GIFS/ TIGGE - An ensemble of NWP ensembles for predicting high impact weather worldwide
Beth Ebert
CAWCR
Abstract:
Imagine an operational ensemble prediction system with (potentially) more than 350 ensemble members, making forecasts of global weather out to 14 days for the benefit of humanity. Any national meteorological centre with internet access could freely access a number of probabilistic and deterministic forecast products for their region, and could request on-demand generation of special guidance products for local high impact weather phenomena such as tropical cyclones and heavy rain events. Is this scenario pie-in-the-sky?
This is the goal of the ambitious Global Interactive Forecast System (GIFS), planned as the culmination of the TIGGE (THORPEX Interactive Grand Global Ensemble) project. This talk will show some early results (generated elsewhere) that confirm that ensemble predictions from multiple models have greater skill than those from single-model ensembles. The next phase of TIGGE will involve distributed access and archival of real-time multi-model ensemble data, with the first prototype being the exchange of ensemble tropical cyclone track predictions. Most NWP track-producing centres have agreed to make their ensemble track forecasts available in real time by August 2008. These can be used to generate multi-model TC products such as strike probability and ensemble intensity forecasts, which could be very useful in the Bureau's tropical cyclone warning centres.
The Bureau's involvement in GIFS/ TIGGE is multi-faceted. We currently send GASP global ensemble forecasts to the TIGGE archive for use in multi-model ensemble research, and anticipate contributing ACCESS ensemble output when it is ready. We have helped develop Cyclone XML (CXML), an exchange format for ensemble TC track data. CAWCR scientists are involved in the GIFS planning process. To help make GIFS a reality, the Bureau should participate in the development and implementation of systems for data exchange, ensemble product generation and dissemination, and verification.
Wednesday 9 April, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
Diagnosing the health of your variational assimilation system. Part II: in Model Space
Chermelle Engel
CAWCR
Abstract:
This presentation is the second in a two-part series. The first presentation introduced diagnoses of the accuracy of paramaters used by variational data assimilation systems using statistics in observation space. This second presentation will address ways to increase the accuracy of data assimilation parameters and the relationship between these implementations and 'degrees of freedom for signal'.
Thursday 10 April, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins St
Oxygen declines in the interior waters of the Subarctic Pacific
Frank Whitney
Emeritus, Fisheries and Oceans Canada
Abstract:
Data collected for 50 years at an oceanic station in the NE Pacific provides evidence of persistent declines in oxygen in waters of 150 to 600 m depth. Oxygen losses are shown to result from decreased ventilation of the upper ocean in a region near the coast of Russia and northern Japan. This area has freshened and perhaps warmed over past decades, consequently waters with densities of 26.5 to 27.0 sigma theta are not being enriched as strongly with oxygen. These waters are eventually transported to the coast of North America, where the impacts of lower oxygen levels are being observed. Over the past several years, fish and crab kills due to hypoxia have been seen along the Oregon and Washington coasts. Also, loss of deep habitat is suggested for some groundfish species along the British Columbia coast.
If time allows, a brief overview of climate change issues being faced by Fisheries and Oceans scientists in Canada will be presented.
Wednesday 16 April, 10.00am, BMRC Seminar Room, 9th floor east, 700 Collins St
The Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative
Rob Allan
Met Office Hadley Centre, Exeter, UK
Abstract:
The Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative is a collaboration between the Queensland Climate Change Centre of Excellence (QCCCE) in Australia and the Met Office Hadley Centre in the UK, in cooperation with the Cooperative Institute for Research in Environmental Sciences (CIRES)-a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado in the USA.
ACRE is an end-to-end project which facilitates both the historical global weather observational data needs of pioneering surface-observations-only climate quality reanalyses, and the seamless feeding of 3D weather products produced by these reanalyses into climate applications and impacts models.
The initial focus will be to support the CIRES/NOAA 20th Century Reanalysis Project, covering the period from 1892 to the present. This reanalysis assimilates surface terrestrial and marine climatic variables (e.g. daily to sub-daily mean pressure, plus monthly sea surface temperature and sea-ice) and uses a Kalman Filter to blend an ensemble of 6-hourly numerical weather prediction model forecasts with the available observations to produce a unique global reanalysis product of weather conditions from the surface to the tropopause at 2 x 2 degree global resolution. At each 6-hourly time step, this reanalysis will produce a 56-member ensemble output and error estimates of historical 3D weather variables over the globe.
ACRE will also support the data needs for even longer CIRES/NOAA surface observations-based reanalyses. The initiative is leading the recovery, imaging, digitisation and archiving of surface observational data coverage for global reanalyses back to the early to mid-19th century, and specifically over the North Atlantic-European region from the mid-18th century to the present.
ACRE is working with the climate applications and impacts community to ensure that the 3D weather variables produced by the historical reanalyses it is supporting are what that community can use. This will extend to ACRE-facilitated reanalyses outputs feeding directly into various production (crop, water, economic etc) and environmental (storm, storm surge etc.) models, and involve working with researchers exploring downscaling techniques or using limited area climate models that are currently fed by existing temporally-limited and non-climate quality ERA or NCEP reanalysis products.
Monday 21 April, 11.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins St
New approaches to flood forecasting.
Ezio Todini
Dept. of Earth and Geo-Environmental Sciences - University of Bologna
Abstract:
In recent years, the availability of new technological tools based on RADAR and Satellite technology opened new perspectives in flood forecasting. Geomorphologic data, land use and soil maps are today widely available on GIS format together with distributed rainfall fields produced using rain gauges, RADAR or Meteosat images. In addition quantitative rainfall field predictions are generated using nowcasting techniques or meso-scale atmospheric models as single predictions or as part of ensemble predictions. This new availability of data combined with the increased power of available computer resources, promoted the development of new technologically advanced distributed physically based rainfall-runoff models. Unfortunately, the level of uncertainty involved in quantitative rainfall field forecasts is still quite large and becomes larger with the increasing lead time.
The aim of current research approaches is to assess and to account for all the sources of uncertainty that converge in flood forecasts and finally to estimate the so called flood forecasting ¨predictive uncertainty¸, which is the key issue in all the decision schemes.
This presentation will discuss recent approaches aimed at assessing and reducing predictive uncertainty in terms of multi-sensor precipitation measurements and distributed rainfall-runoff modelling.
RAIN-MUSIC, a recent multi-sensor technique will be introduced, which is based upon the use of block-Kriging and of Kalman filtering to combine areal precipitation fields estimated from meteorological radar to point measurements of precipitation, such as the ones provided by a network of rain-gauges, and, when available, to Satellite precipitation estimates. Block Kriging is used to estimate the average field over the radar pixels and its variance from the point rain gauge measurements, while a posteriori estimates are found using a Kalman filter which combines, in a Bayesian framework, the a priori estimates provided by the RADAR with the block Kriged measurements provided by the gauges.
An original formulation of Kriging with uncertain point precipitation measurements had to be developed in order to use the approach in real time, by using at each step in time a constrained Maximum Likelihood estimator where non negativity constraints were added to prevent negative values in the Kriging weights. Last but not least, the use of anisotropic variogram functions was also incorporated into the Block Kriging formulation in order to better reproduce rainfall patterns.
Finally, a recent physically meaningful distributed model, the TOPKAPI, will also be presented and discussed as the appropriate approach to benefit from the available geomorphologic data, land use and soil maps together with the distributed precipitation information provided by the RADAR or the multi-sensor RAIN-MUSIC type products.
Wednesday 07 May, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins St
Climate Change and Probable Maximum Precipitation
Rob Smalley
CAWCR BoM
Abstract: Probable Maximum Precipitation (PMP) is one of the required inputs for estimating the PMP design flood and for dam spillway design. In estimating the PMP, currently no allowance is made for long-term climatic trends. This study aims to assess how climate change might affect PMP estimates. Since PMP estimates could be considered as an asymptote which rainfall events converge to but not exceed, it is not possible to use only previous significant rainfall events in assessing for change over time. Instead, changes in the main factors used in PMP estimation, including moisture availability and storm efficiency have been assessed. Analysis of storm events over the past century indicate that storm efficiency of the significant rainfall events have not changed, although there are a number of significant changes in extreme moisture availability. Projected changes of extreme precipitable water into the 21st century indicate a general increase; however there are regions with decreases. An extended high quality daily rainfall dataset, which has undergone additional quality checks, is used to assess trends of extreme rainfall indices throughout the 20th century. This provides an increased coverage across Australia and is an improvement on that used for the IPCC AR4. A Taylor diagram is used to compare the rainfall indices from a number of global climate models with gridded observations of the rainfall indices and their trends. The climate models are also used to provide projections of extreme rainfall throughout the 21st century. The implications of the rainfall projections on PMP estimates will be discussed.
Monday 12 May, 11.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins St
Progress towards operational implementation of enhanced vertical resolution in the Met Office Unified Mod
el.
Stuart Webster
Flow over Orography Research Scientist, Met Office
Abstract:
The Met Office global operational forecast version of the Unified Model currently employs a resolution of 40
km in the horizontal and 50 levels in the vertical. Enhancements to 25 km and 70 levels are planned in the
next year. This talk focusses on the 70 levels enhancement and so describes both the motivation behind the c
hoice of the 70 levels and the progress made towards operational implementation.
More specifically, the talk will focus on the two major numerical issues that have been addressed in the dev
elopment and testing of the new levels set. The first issue was the reduced model stability due both to the
finer boundary layer resolution (there are now 21 levels rather than
13 levels spanning the lowest 3 km) and to the higher model lid (which is now at 80 km rather than 63 km). T
he second issue was to eliminate (or reduce as much as possible) the model level dependencies in the paramet
rizations of physical processes. Examples of both issues and the solutions implemented to resolve them will
be described and illustrated.
Finally, with the above issues now resolved, the anticipated improvements to both the model performance and
model skill from using 70 levels will be highlighted.
Wednesday 14 May, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins St
The east Australian pressure gradient index (GDI)
Clinton Rakich
BoM NSWRO
Abstract:
The Gayndah-Deniliquin index (GDI), a measure of the north-south atmospheric pressure gradient across eastern Australia, is presented. The 113 year long GDI record reveals strong interannual to decadal scale variability in zonal geostrophic wind flow across eastern Australia. The GDI, as a measure of easterly geostrophic wind strength and associated moisture transport from the Pacific Ocean, is shown to be significantly correlated with summer rainfall over vast areas of the Australian continent, especially over the Murray Darling Basin and the state of New South Wales. The latest abrupt decline in the GDI, which commenced around 2001, corresponded with the onset of a severe prolonged drought across eastern Australia.
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We demonstrate that the northern and southern poles of the MSLP derived GDI are differentially influenced by El Ni·o-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Understanding the effects of these interactions between SAM and ENSO on moisture advection across eastern Australia could have important implications for future Australian climate variability and climate change. The IPCC 4th assessment report summarises the uncertainty associated with projections for Australian summer rainfall by stating 'more broadly, across the continent summer rainfall projections vary substantially from model to model, reducing confidence in their reliability'. Results of an assessment of the strength of the GDI - rainfall relationship in the IPCC AR4 model output data for the 20th Century will be presented.
Friday 23 May, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins
St
Operational Tsunami Prediction and Assessment System (OTPAS)
HengKek Choo
National University of Singapore
Abstract:
I will describe the prototype system and component parts that we have implemented or plan to implement. The components include: Antelope, a moment tensor program, a tsunami propagation model, a data-driven tsunami prediction model, a sea-level monitoring facility, a run-up model, and an alert system.
Wednesday 28 May, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins
St
A New Paradigm for Radar Sensing of the Atmosphere: An Overview of the CASA Project
Frederick H. Carr
University of Oklahoma
Abstract:
multi-partner research center known as the Center for the Adaptive Sensing of the Atmosphere (CASA) has been formed to apply advances in radar engineering (low-cost X-band radars), computer science (distributive, collaborative, adaptive sensing), atmospheric science (storm-scale data assimilation and prediction) to improve the forecasts and warnings of hazardous weather. An overview of the project will be given along with examples of how fine-scale radar operations can detect tornadoes and other phenomena not seen by the large S-Band National Weather Service radars.
Wednesday 28 May, 12.00pm, BMRC Seminar Room, Level 9th floor east, 700 Collins
St
Understanding Subsurface ENSO Dynamics for Improving Model Analysis
Jaclyn Brown
CAWCR CMAR
Abstract:
We present a physical energy-based framework that is a useful tool for understanding ENSO dynamics. We focus on three key characteristics of the tropical Pacific Ocean: the wind power, the buoyancy power, and the available potential energy. Wind energy is supplied to the ocean when the wind blows in the same direction as the surface currents. It is removed from the system when the wind blows in the opposite direction. The wind power generates a buoyancy power that raises or lowers the isopycnals, leading to thermocline depth anomalies. The available potential energy is largely a measure of the thermocline slope. A La Ni·a year has a strongly sloped thermocline which has a high available potential energy, and El Ni·o has a flatter thermocline, and less available potential energy. The wind power and available potential energy are approximately 90 degrees out of phase, with wind power leading available potential energy by four to eight months. The system described is similar to the recharge-discharge oscillator but is based on rigorous conservation laws. It also helps us understand how energy is transferred from the surface to the subsurface
From analyzing these energy variables we derive two energy-based metrics, which allow us to compare how models simulate ENSO events. The first of our metrics (the efficiency of energy transfer from the surface to the thermocline) measures how efficient the wind power is in creating available potential energy, hence thermocline slope anomalies and ENSO events. The second metric measures the decay rate of the available potential energy.
These metrics provide a useful tool for understanding models differences in the way they represent ENSO. Our energy-based metrics provide a way to give a basin-wide measure of how energy is transferred differently between models and how they dissipate this energy, regardless of smaller model differences such as grid size and friction schemes. In this study we compare ocean-only models, data assimilations, and coupled IPCC AR4 models. For example, some models have exceptionally strong windstress, but compensate by dissipating most of the energy in the mixed layer. Typically, coupled models are less efficient in transferring energy to the thermocline and more dissipative than ocean-only models and data assimilations. Our metric provides a simple, yet effective method of understanding model differences so that further progress can be made.
Wednesday 18 Jun, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins
St
Tropical cyclones, climatic variation and economics in the Caribbean
Soloman Hsiang
Columbia University
Abstract:
For populations with footprints that are small compared to tropical cyclone scales, basin-season estimates of storm activity may not be the most useful measure for policy or storm-impact analysis. I develop high resolution storm incidence measures, reconstructing estimates of incidence using commonly available historical data and a parameterized storm structure. The impact of geographic and inter- temporal variation of storm-risk on country-level economic measures is measured and analyzed. Implications for conceptualizing the costs of global climatic change and regional insurance mechanisms are discussed.
Wednesday 20 Aug, 10.00am, BMRC Seminar Room, Level 9th floor east, 700 Collins
St
Ozone
Lilia Deschamps
CAWCR BoM
Abstract:
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