Chairs
Dr Michael Wehner, Lawrence Berkeley National Laboratory, USA
Dr Michael Wehner, Lawrence Berkeley National Laboratory, USA
Dr Michael F Wehner is a senior staff scientist in the Computational Research Division at the Lawrence Berkeley National Laboratory. Dr Wehner’s current research concerns the behaviour of extreme weather events in a changing climate, especially heat waves, intense precipitation, drought and tropical cyclones. Before joining the Berkeley Lab in 2002, Wehner was an analyst at the Lawrence Livermore National Laboratory in the Program for Climate Modeling Diagnosis and Intercomparison. He is the author or co-author of over 170 scientific papers and reports. He was a lead author for both the 2013 Fifth Assessment Report of the Intergovernmental Panel on Climate Change and the 2nd, 3rd and 4th US National Assessments on climate change. He is currently a lead author for the upcoming Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Dr Wehner earned his masters degree and PhD in nuclear engineering from the University of Wisconsin-Madison, and his bachelors degree in Physics from the University of Delaware.
13:30-14:00
What can storm-scale models tell us about climate change impacts on extreme rainfall?
Dr Andreas Prein, National Center for Atmospheric Research, USA
Abstract
Simulating storms that cause extreme rainfall accumulations has been a long-standing challenge in weather and climate modelling. Tremendous improvements have been made over recent decades due to advances in models and computational resources that nowadays allow us to explicitly simulate storm-scale dynamics within models. This results in a step-improvement in simulating extreme rainfall and allows unprecedented insights into climate change impacts on rainfall extremes. This talk will exemplify the added value of simulating extreme rainfall producing storms in storm-scale models compared to coarser-resolution models. It will be shown how the most important storm characteristics that are associated with flooding (eg, rainfall rates, storm movement speed, and storm spatial extent) are simulated in storm-scale models and how these characteristics are projected to change in future climates. Storm-scale model-based changes in future rainfall extremes will be summarized and areas of uncertainty and opportunities for research will be highlighted.
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Dr Andreas Prein, National Center for Atmospheric Research, USA
Dr Andreas Prein, National Center for Atmospheric Research, USA
Dr Andreas Prein is a scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, USA, where he is working in the Capacity Center for Climate and Weather Extremes. Dr Prein has a PhD in Physics and a Master in Environmental System Sciences from the University of Graz in Austria. He is an expert in high-resolution climate modelling and observational data analysis. He is interested in the interaction between the climate system and weather extremes. Most of his work focuses on convective extreme events such as extreme precipitation and hail.
14:00-14:30
Using a convection permitting model ensemble for projecting future change in precipitation extremes
Dr Elizabeth Kendon, Met Office Hadley Centre, UK
Abstract
For the first time internationally a model at a resolution on par with operational weather forecast models has been used for national climate scenarios. As part of the UK Climate Projections (UKCP) project, an ensemble of 12 projections at 2.2km resolution have been carried out over the UK. These were launched in September 2019, with the aim of providing an improved simulation of extreme precipitation and also other high-impact events at local scales for the coming decades. At such high (2.2km) resolution, convection can be represented explicitly (‘permitted’) without the need for a parameterisation scheme, leading to a much more realistic representation of hourly precipitation characteristics, including extremes. In this talk initial results from the UKCP local (2.2km) projections, including changes in hourly precipitation extremes, will be presented.
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Dr Elizabeth Kendon, Met Office Hadley Centre, UK
Dr Elizabeth Kendon, Met Office Hadley Centre, UK
Dr Elizabeth Kendon has 13 years of experience working at the Met Office Hadley Centre on regional climate modelling. She currently leads a team of scientists using very high resolution (kilometre-scale) models to study climate change, with a main focus on gaining a better understanding of extreme rainfall processes and their future change. Her work has been pioneering in the field of convection-permitting climate modelling, with a high profile paper in Nature Climate Change (Kendon et al, 2014) and in 2018 she received the LG Groves Memorial Meteorology Prize in recognition of this work. She is currently leading work on the first ensemble of climate simulations at convection-permitting scale over the UK for the next set of climate projections (UKCP18). These will be delivered in September 2019, and will be the first time internationally that convection-permitting projections will be provided in national climate scenarios. She also recently worked on the FCFA IMPALA project involving convection-permitting climate simulations over Africa, with the first future change results published in Nature Comms (Kendon et al, 2019). Lizzie also has a key role in the ERC INTENSE project analysing intense rainfall, NERC FUTURE-STORMS project looking at changes in high impact events and is participating in the EUCP project which includes carrying out coordinated convection-permitting climate simulations over Europe. Lizzie has a PhD in atmospheric science from Imperial College London (2005), an MSC with distinction from Manchester University (1999) and a 1st class BAHons and MSci in Natural Sciences (Physics) from Cambridge University (1998).
15:30-16:00
The role of stratification changes for the future European precipitation climate
Professor Christoph Schär, ETH Zurich, Switzerland
Abstract
There is tremendous interest into future changes of the precipitation climate, as precipitation touches upon a large number of human activities. The scientific argumentation often invokes changes in large-scale circulation and absolute humidity. Here another important aspect is considered, namely the role of stratification (or lapse-rate) changes. These changes are closely linked to climate change, as global warming will imply substantial shifts in the moist-adiabatic lapse rate. Lapse-rate changes have already been identified to instigate important impacts in the tropics, but they are also important for European climate change. Here an overview on lapse-rate changes is provided, together with examples from two recent publications. It is demonstrated that lapse-rate changes are particularly important for the European summer climate and strongly influence the projected drying in the Mediterranean, as well as short-duration precipitation events and the associated Clausius-Clapeyron scaling. It is argued that lapse-rate changes can be considered more reliable than circulation changes, and thus may help adding more confidence to some specific aspects of European climate change projections.
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Professor Christoph Schär, ETH Zurich, Switzerland
Professor Christoph Schär, ETH Zurich, Switzerland
Professor Christoph Schär obtained his Physics degree and PhD in atmospheric dynamics from ETH Zurich. He had post-doctoral positions in the USA (Yale, New Haven; University of Washington, Seattle). He has been a professor at ETH since 1992. He served on a number of committees, among these as a member and chairman of the Scientific Advisory Committee of the ECMWF (Reading, UK), in the editorial boards of several leading journals, as a contributing author of the 3rd and 4th IPCC assessment reports, and as a lead author of the 5th IPCC assessment report. He and his group have expertise in atmospheric dynamics and numerical modelling. His recent work addresses the development and exploitation of high-resolution climate models, with a particular view to better understand heavy precipitation events.
16:00-16:30
Using high resolution modelling to understand the urban influence
Professor Jason Evans, University of New South Wales, Australia
Abstract
With the ever growing population living in cities worldwide, it is increasingly important to understand how the expanding cities influence their own climate. The urban environments' effect on temperature, referred to as the urban heat island (UHI), generally means urban environments are several degrees warmer than the surrounding region. While there are many factors that influence the UHI intensity, these are reasonably well understood. The influence of urban environments on precipitation is more complicated and involves the various ways in which the city (including the UHI) can alter the local circulation of the atmosphere. Here Jason Evans discusses several mechanisms to alter the local circulation and impact precipitation over urban areas. He suggests that large cities within the tropics (on coasts) are ideal places to observe these effects and show some results of studies looking at Kuala Lumpur, Malaysia, and Jakarta, Indonesia. In order for climate models to capture the UHI and changes in local circulation, resolutions at the kilometre scale are required.
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Professor Jason Evans, University of New South Wales, Australia
Professor Jason Evans, University of New South Wales, Australia
Professor Jason Evans gained his PhD from the Australian National University before taking up a research position at Yale University in the USA. He is currently a Professor in the Climate Change Research Centre at the University of New South Wales, Sydney, Australia. He is a chief investigator in the Australian Research Council Centre of Excellence for Climate Extremes. He is co-Chair of the Global Energy and Water Exchanges (GEWEX) Hydroclimate Panel and a member of the Science Advisory Team of the Coordinated Regional Downscaling Experiment (CORDEX), both elements of the World Climate Research Programme. He is a lead author of the IPCC special report on Climate Change and Land, and editor of the Journal of Climate. His research focuses on the climate system particularly in regards to land-atmosphere interactions, the water cycle and regional climate change.