GEWEX/WCRP Extremes Workshop, Vancouver, Canada, May 2008 ( Ron Stewart )

1. Briefing session on activities/workshops on extreme events • GEWEX/WCRP Extremes Workshop, Vancouver, Canada, May 2008 (Ron Stewart) • IPCC Special Report of extreme events and disasters, Oslo, Finland, March 2009 (Francis Zwiers) • Workshop on Extreme events in climate and weather, Banff, Canada, August 2010 (Peter Guttorp) • Weather and Climate Extremes During the Past 100 years, Diessenhofen, Switzerland, 7-9 June 2010 (Urs Neu) • IMILAST project (Intercomparison of mid latitude storm diagnostics) (Urs Neu) • Workshops on North American and global drought monitoring, Asheville, USA, April 2010 (Rick Lawford) • GEO-DRI workshop Winnipeg, Canada, May 2010 (Rick Lawford) • Storm Surge Risk and Management Congress, Hamburg, Germany, 13-17 September 2010 (Hans von Storch) • Workshop on Extremes in Weather and Climate, Bonn, Germany, June 2010 (Petra Friederichs, Douglas Maraun) • Creating surface temperature datasets to meet 21st Century challenges, Exeter, UK, September 2010 (Albert Klein-Tank) • NASA NEWS extreme workshop, Grand Forks, ND, USA, 15-16 July 2010 (Xiquan Dong) • International Workshop on recent achievements in study of extreme events, Potsdam, 27- 29 Sep 2010 (Norbert Marwan, presented by Gulev)

2. GEWEX/WCRP Extremes WorkshopVancouver, May 2008Ron Stewart Within GEWEX/WCRP ... To better understand the occurrence, structure, and role of extremes within the climate system. To contribute to their better prediction at various time scales and to addressing societal concerns. This workshop began to address such issues: Assessments of the current situation Suggestions for moving ahead

3. CURRENT STATUS Issues relevant to this current workshop ... Statistical Analysis of Extremes  • There is no single objective universal definition of extremes  • Statistical analysis may not reflect the true trends in extremes. Land use changes, soil moisture effects, and vegetation changes may alter the nature of extremes  • Many national data sets are not available for the public • Many data sets are not sufficiently homogeneous and the metadata are incomplete • There are problems in instrument differences • The quality of data from some nations is suspect • It is difficult to characterize the performance of models in predicting extremes because the model likely has been changed since the last time an extreme event occurred  Assessment of the Effects of Climate Change on Extremes • There is growing interest in providing analyses of the impacts of extremes  • Recent trends are needed to assess if climate models reproduce these • Statistical studies are needed for downscaling model outputs for extremes

4. MOVING FORWARD • Develop a small set of definitions of drought  • Agree on the complete data needed to characterize extremes • Develop standardized precipitation data sets that include wind effects. • Assess Global Precipitation Climatology Project satellite-based products  • Develop an inventory of data sources, data types, and metadata • Develop a listing of ‘chains-of-events’ associated with Extremes events • Undertake studies of frequency of extremes using satellite/radar products • Assess the need for data rescue efforts for data records in many countries. • Develop stronger links with the ensemble forecasting community  • Find areas with large differences in extremes using model and actual data  • Assess the feasibility of high-resolution models in downscaling for extremes • Summarize work on extremes within GEWEX and other efforts Many of these ideas will undoubtedly be mentioned here ...

5. IPCC Special Report of extreme events and disasters Oslo, Finland, March 2009 Francis Zwiers

6. Banff workshop on climate and weather extremes August 23-27, 2010

7. Participants 32 participants from 7 countries Mix of hydrologists, climatologists and statisticians Talks in the morning, group discussion in the afternoon Goal: Set directions for research in extremes and climate

8. Some issues • Comparing climate models to data • Upscaling • Downscaling • Meaning of value for a grid square • Multivariate extreme values • Often need conditional distributions • Spatial and space-time extremes • Nonstationarity

9. Results • Technical areas for research • Extreme value models nonstationary in space and time • Multivariate models where extremes in different components do not coincide • Tractable space-time models for extremes • Extreme index numbers • Meeting report • Working groups • Heat wave • Skill scores for climate model

11. Specific Approach • take a broad perspective covering not only weather and climate extremes, but also extremes in chemical climate, in land-surface processes, in the oceans, and the sea ice Weather and Climate Extremes During the Past 100 years Diessenhofen, Switzerland, 7-9 June 2010 S. Brönnimann, J. Luterbacher, U. Neu • Goal and objectives: • Discuss how to achieve • knowledge on the processes leading to extremes • suitable data products that allow analyzing extremes • model systems capable of reproducing extremes • methods and techniques for assessing and evaluating extremes and for communicating and cooperating across disciplinary boundaries

12. Example: Cross-validation of observations and numerical products S. Brönnimann et al.

13. WCRP objectives concerned: • design an intercomparison framework through which both observations and climate model representations of extremes and projections of climate can be assessed, and by which changes in climate extremes can be better evaluated • assess the observational and dataset framework for study of global extremes Some outcomes • The reconstruction of long data series of extremes is very important, including quality control and homogenization • Intensify the search for possibilities of cross-validation of numerical reconstruction and observed events (case studies). • Proposition to make a “blind” comparison using a common data set and a common set of questions and giving that task to different groups,i.e. intercomparison of not only methods, but whole approaches to tackle a question • Multidecadal variability of occurrence influences societal memory of extremes and thus preparedness

14. Aims of the project • to provide an assessment of different methodologies,for both cyclone identification and cyclone tracking • to intercompare the metrics of mid latitudinal cyclone activity (identification/tracking) used for different purposes • to point out the specific informations that can be drawn from specific methods IMILAST Intercomparison of Mid-latitude Storm diagnostics U. Neu, I. Rudeva, S. Gulev, X.L. Wang, K. Keay, I. Simmonds, M. Inatsu, and the IMILAST team • What is the project about? • Characteristics of cyclone activity and quantification of trends strongly depend on the methodologies used for storm track detection • Knowledge about advantages and restrictions of different schemes must be obtained to be able to provide a synthesis of results and proper interpretations Sponsored by Swiss Re

15. Total number of cyclones per year over the Northern Hemisphere M12 Rudeva/Gulev (SAIL/IORAS) M10 Keay/Simmonds (Melbourne Univ.) M09 Wang/Serreze (Environ. Canada) M21 Inatsu (Hokkaido Univ.) Result examples Differences in cyclone numbers over the NH from different datasets (w.r.t.SAIL/M12) M09-M12 M10-M12 M21-M12 Rudeva & Gulev, SAIL/IROAS

16. http://www.proclim.ch/IMILAST/index.html WCRP objectives concerned: • summarize, compare and assess definitions of climate extremes and develop a common language amongst researchers and end users • design an intercomparison framework (...) by which changes in climate extremes can be better evaluated • methodological aspects of the quantitative estimation of different climate extremes ProjectPlan • Collected the existing identification and tracking methods • Defined a standard intercomparison experiments(specific data sets, list of characteristics to be delivered) • - Set up a project data server and allocated data sets for the intercomparison experiments • Run intercomparison project (started summer 2009) • Collection of results / analysis work • Workshop, discussion of analysis (March 2011) • Preparation of draft report • Review of draft report • Follow-up workshop (if necessary) • - Preparation of Final Report

17. GEO Drought Workshop Summaries: - GEO Drought Workshop (Asheville, NC; April 21-22, 2010) - GEO-DRI Workshop (Winnipeg, MB; May 10-11, 2010) by Rick Lawford

18. Workshop on Drought Monitoring with an emphasis on Global • Drought Monitoring (Asheville, NC – April 21-22, 2010) • To refine the definitions of drought and to specify preferred • averaging times for the SPI index. (The SPI index has been • chosen at a December 2009 workshop in Lincoln, NB as • the first of a handful of indices that NHMs will use to • characterize drought.) • 2. To review ideas and solicit support for a Global Drought • Warning System (or a global drought monitor with a • similar name)

19. Potential Cooperative North American Projects • The April GDAW discussed moving some US products to the NA scale: • North American Drought Outlook • North American Drought Impacts Reporter • VegDRI for North America • Satellite-based observations of vegetation conditions • Climate-based drought index data • Biophysical characteristics of the environment

20. Future Activities in Drought Monitoring A comprehensive user manual for the SPI will be developed Two working groups with global representatives and UN Agencies and Research Institutions will be established to comprehensive indices to characterize agricultural and hydrological droughts. Plans are being developed to establish a Global Drought Early Warning System initially thrrough a Clearing House for drought information. Candidate leads for this clearing house are the NIDIS portal and WMO. A study of drought indices in different regions of North America will be undertaken (Part of US GEO – Canada GEO activities). 20

21. GEO-DRI Workshop (May 10, 11, 2010): Approximately 30 people from six countries met in Winnipeg to discuss the contributions that DRI and similar regional drought projects could make to the Global Earth Observation System of Systems (GEOSS). WORKSHOP OBJECTIVES: 1) To review the activities that are being undertaking within GEO related to drought, drought impacts, drought monitoring and drought prediction. 2) To identify the information needs for drought information for the purposes of monitoring, prediction and impact assessment. 3) To review the results of relevant drought research that could contribute to the GEO drought objectives. 4) To develop an action plan for GEO drought activities that would encourage the convergence of GEO drought projects and related drought research and operational activities towards one or more component(s) of GEOSS.

22. RECOMMENDATIONS: GEO Agriculture and Water SBAs should work more closely together in addressing drought. In addition, the Canada - US GEO prairie testbed should be expanded to include the Kenaston soil moisture site and west to east soil moisture gradients. Drought monitoring and drought impact assessments should be planned and implemented together. The interpolation of impact information can only be effectively interpreted within the context provided by drought monitoring. GEO should focus on the development of standards and protocols for the use of specific water cycle variables and more general drought indices. This could also include the development of “citizen science” to enhance water cycle observations and drought impacts for drought monitoring. An assessment of the representativeness of integrated soil moisture products should be undertaken. GEO should consider the establishment of a drought community of practice to discuss best practices, transfer of local developments between nations and projects, etc.

23. Hartwig Kremer, Hans von Storch and Marcus Lange GKSS Research Center, Geesthacht, Germany

24. Hosted by the Institute for Coastal Research@GKSS in collaboration with the KlimaCampus (CLISAP) of the University of Hamburg the international Congress on Risk and Management of Current and Future Storm Surges took place at Hamburg University between 13 and 17 September 2010. Organized by the international global change research network LOICZ (Land-Ocean Interactions in the Coastal Zone) which is a core project under IGBP and IHDP, more than 200 participants representing over 30 nations found their way to Hamburg to attend this congress addressing storm surges since the last two decades. The main goal of this congress was to move towards overcoming the fragmented views and discussions that characterize the scientific as well as the user perspectives on this global coastal hazard and its regional specifics. A variety of international and national sponsors and supporting agencies reflect the wide and multidisciplinary interest the congress attracted including UNESCO’s Intergovernmental Oceanographic Commission, IOC, the European Space Agency, ESA, as well as the National Oceanographic and Atmospheric Administration of the USA, NOAA, the coastal engineering network COPRI and multiple national organisations such as the Federal Maritime and Hydrographic Agency, BSH, the German Weather Service, DWD, and Hamburg Port Authority.

25. The 2010 Storm Surge Congress centred on questions of coastal system and community vulnerability, risk and risk perception as well as ways for adaptation. • As a consequence the Congress invited numerous scientific experts from all traditionally involved disciplines plus a multiplicity of stakeholders, coastal users, the information services, the insurance and re-insurance business and decision-makers as well as city and coastal planers and engineering communities. • In order to meet this challenge of being truly interdisciplinary and to attract both, the natural and social scientists as well as humanities the congress comprised five days of interdisciplinary scientific sessions, two open panel discussions, a regional side event and a field trip illustrating past and current efforts of a tidal harbour and city to cope with flood risk and to prepare for future hazards. • The overarching aim was to provide answers to the two questions: • How do we deal with the present level of risk? • How do we respond to changing future conditions?

26.  An important issue was the clear understanding that man-made climate change is merely one issue when dealing with the hazards of storm surges – other issues such as water works, urban development and population growth, extraction of sand and gas are often of equal or even larger importance for changing local risks than climate change. For overcoming the fragmentation when dealing with storm surges as a global multi-scaled coastal hazard it is critical to enable and improve ways of enhancing cross disciplinary and cross cultural collaboration. The Hamburg Storm Surge 2010 Congress was a show case for the willingness and ultimately also the ability of different disciplines including humanities to exchange their views and actively contribute to this process. It also was a show case of non sensational communication incl. recognition of alternative knowledge claims and sharing this with public media. A second conference will be organized in 2013, again in Hamburg. A more detailed report is presently prepared for EOS or a similar outlet.

34. Creating surface temperature datasets to meet 21st Century challenges, UK Met Office, Exeter, 7th-9th Sept 2010by Albert Klein Tank Peter Thorne (NOAA/NCDC), Peter Stott (Met Office, UK) 80 participants (climate, metrology, statistics, software, economics, developing and developed world) Open and transparent key principles More details at www.surfacetemperatures.org and http://surfacetemperatures.blogspot.com/ - including expanded outcomes presentation To be written up in BAMS, possibly stats society journal, Japanese Met Soc and also as WMO TD

35. Key Outcomes • Creation of a single databank for all surface observations (not just Temperature). • Monthly, daily, synoptic • Provenance and version control • Several stages from hard copy / digital images to consolidated databank in common format • Multinationaleffort • Crowdsourcing being investigated to digitise huge number of images held • Multiple, redundant efforts at creating data products from the databank. • Distinct ways of doing homogenisation and QC (latter important as well, especially for extremes) – only way you truly learn what you can / cannot say • Published methodologies, availability of audit trail, code etc. strongly encouraged

36. Key outcomes (cont) • Common benchmarking exercise (cyclical – 3 years envisaged) • Double blind • Direct analogs to the databank (space and time sampling) • Range of complexity and assumptions – really test algorithm performance • Assessment for not just trends – extremes as well. • Consideration of interpolationtechniques • Development of assessment dataset for benchmarking • New interpolation methods, including joint spatio-temporal treatments • Provision of user tools • Graphical • Uncertainties • Guidance as to fit-for-purpose of different products • Governancestructure that reports to WMO and possibly BIPM (metrology) and TIES (statistics)

37. Looking for involvement • Will only be successful if people become involved, and we are looking to build on existing efforts not reinvent the wheel • Please provide feedback either through the blog or to relevant contact • Overall – Peter.Thorne@noaa.gov • Databank – Jay.lawrimore@noaa.gov • Benchmarking – Kate.Willett@metoffice.gov.uk • Governance – Peter.Stott@metoffice.gov.uk

38. NASA NEWS Drought and Flood Extreme Workshop at University of North Dakota, July 15-16, 2010 Co-Chaired by Xiquan Dong, University of North Dakota Yi Deng, Georgia Institute of Technology The overarching science goal of the extreme working group is to understand the variability of global/regional hydrological extremes across seasonal to decadal time scales, identify the linkage between changes in the characteristics of these extremes (e.g., frequency, severity, duration, and sequencing) and the global climate change, and explore the predictability of these extremes from seasonal to decadal time scales. Eventually, we should translate better observations and improved understanding of hydrological extremes into practically relevant information for multiple stakeholders in sectors such as agriculture, energy, water resource and risk management. 38

39. Objectives of NEWS Extreme group • Generate a global database about the hydrological • extremes from multiple data sources, such as their • frequency occurrence and trends of these extremes, as well • as their association with other climate/weather phenomena • over past 30 years, such as global warming. • Investigate the regional extremes and their trends, as • well as their association with different monsoon systems. • This investigation will build upon our current extreme • study at the U.S. SGP region, take advantage of the • multiple datasets constructed by NASA NEWS project. • Explore the predictability of hydrological extremes on • different time scales and collaborate with other groups to • project future extreme events under global warming 39

40. Data Sets and Methods used We think it is important to build a global database about the hydrological extremes (droughts and floods) from widely used datasets (e.g., PDSI, GPCP, MERRA, etc) with the same criteria, such as the spatial scale (a grid box of 2.5ox2.5o), severity (±2 standard derivations), duration (last 3-4 months). 40 Drought case Wet case

42. Aims • highlight potential directions and perspectives of further research • improve understanding of forming extreme events • reliability of their prediction • tools for the evaluation of predictions Organisers: Norbert Marwan, Jürgen Kurths, Holger Kantz http://extremes.pik-potsdam.de

43. Interdisciplinary Focus: theoretical physics, mathematics, climatology, hydrology, economy, geophysics, engineering Expected Outcome • cross-fertilisation between the different disciplines • new aspects on prediction and modelling of extremes from the view of different disciplines • Highlights: • frequency of extremes related to climate change • reliability of extremes‘ prediction and regional projections • socio-economic impact and human behaviour