85th AMS Annual Meeting

Monday, 10 January 2005
Climate extreme indices via regional climate change workshops
Thomas C. Peterson, NOAA/NESDIS/NCDC, Asheville, NC
Poster PDF (173.8 kB)
In the past, analysis of long-term global climate change has focused on changes in mean values. However, changes in extremes – e.g., the occurrence of heat waves or the 90th percentile of minimum temperature observations – requires long-term digital daily data. Unfortunately, long-term digital daily data are not available internationally for large portions of the world. In the 2002 “global” analysis by Frich et al. (2002), almost no analysis of extremes was possible for most of Central and South America, Africa, and southern Asia. This paper reports on the progress and status of a concerted series of efforts to remedy that situation as well as showing some results of new analyses of changes in extremes in these regions.

Two complimentary efforts are moving forward to address this problem and they are both coordinated by the joint World Meteorological Organization Commission for Climatology (CCl) / World Climate Research Programme (WCRP) project on Climate Variability and Predictability (CLIVAR) Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). The first involves the international coordination of a suite of climate change indices derived from daily data which primarily focus on extremes. Software to calculate these indices has been developed on the ETCCDMI’s behalf by Environment Canada. A prime benefit of this effort is that new analyses for regions or countries will be able to fit together seamlessly as they will all calculate the same indices in exactly the same manner. A global analysis paper will be led on the ETCCDMI’s behalf by the Hadley Centre, UK Met Office.

But analyses software doesn’t do any good without data. In many parts of the world enough daily data have been digitized to contribute to an analysis but institutions are reluctant to part with data to permit someone outside their country to analyze how their extremes are changing. This is a far more difficult problem to address. The solution proposed by the ETCCDMI’s predecessor was to hold regional climate change workshops modeled after the Asia Pacific Network workshops (Manton et al., 2000; Peterson et al., 2001). Two regional climate change workshops were held in 2001, one Kingston, Jamaica (Peterson et al., 2002) and one in Casablanca (Easterling et al., 2003). Recognizing the successes and problems of these workshops, the ETCCDMI has embraced holding a series of additional regional climate change workshops to fill in major blank areas of the globe.

These workshops bring together participants from every, or nearly every, country a region for a combination of seminars and hands-on analyses of the daily data they bring with them. Calculating the indices at a regional workshop provides the synergy of immediately being able to see how results compare across borders. With the Caribbean workshop we were able to release all the data. While that remains a goal, realistically not every country is expected to be willing to release their daily data. However, we do anticipate that we should be able to release indices derived from the data. Indices of, for example, the number of days per year with precipitation above the 90th percentile (based on data from a set base period), provide valuable information for climate change analysis from both an observational point of view and for comparisons with model output. Funding for these workshops has been provided by the U.S. State Department via GCOS, the Inter American Institute for Global Change Research (IAI), SysTem for Analysis, Research and Training (START), WCRP and CCl. The workshops being held or planned include:

1) Southern Africa: Held in Cape Town, South Africa from May 31 to June 4, 2004. Lead: Bruce Hewitson (host, University of Cape Town).

2) Southern 3/4s of South America: Ecuador, Peru, Brazil and all countries south of them, to be held August 9-14, 2004 in Maceio, Brazil. Leads: Luiz Molion (Host, Universidade Federal de Alagoa), David Karoly (U. of Oklahoma) and Tom Peterson (NCDC/NOAA).

3) Southwest Asia: Yemen to Georgia, Turkey to Iran. To be held in Alanya, Turkey, October 4-9, 2004. Leads: Serhat Sensoy (host, Turkish State Meteorological Service), Valery Detemmerman (WCRP), and Tom Peterson (NCDC/NOAA).

4) Central and northern South America: Mexico to Colombia to French Guiana. To be held in Guatemala, November 8-12, 2004: Leads: Patricia Ramírez Obando (Comité Regional de Recursos Hidráulicos del Itsmo Centroamericann, Costa Rica), Enric Aguilar (Universitat Rovira i Virgili, Tarragona, Spain), Russ Vose (NCDC/NOAA), and Phil Jones (Climate Research Unit, University of East Anglia, UK).

5) Southern Asia: Bangladesh to Pakistan to Kazakhstan to China. Tentatively planned to be held in Pune, India pending funding, by Februrary 2005. Probable leads: Rupa Kumar Kolli (host, Indian Institute of Tropical Meteorology), Tom Peterson (NCDC/NOAA), Panmao Zhai (Chinese Meteorological Agency), Russ Vose (NCDC/NOAA).

This paper will report on the status and accomplishments of these workshops and show preliminary results from several analyses of extremes for these regions.

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