Climate change detection and indices

"Confidence has increased that some extremes will become more frequent, more widespread and/or more intense during the 21st century" (IPCC, 2007). As a result, the demand for information services on weather and climate extremes is growing. The sustainability of economic development and living conditions depends on our ability to manage the risks associated with extreme events. Many practical problems require knowledge of the behaviour of extreme values. In particular, the infrastructures, public services and other facilities we depend upon for food, water, energy, health, shelter and transportation are sensitive to high or low values of meteorological variables.

To gain a uniform perspective on observed changes in weather and climate extremes, the joint CCl/WCRP-Clivar/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI) has defined a core set of descriptive indices of extremes. The indices describe particular characteristics of extremes, including frequency, amplitude and persistence. The core set includes 27 extremes indices for temperature and precipitation.

Resources on indices including software, climate extreme indices dataset, publications and other resources can be accessed to through the ETCCDI resource and information web site maintained by the University of Victoria, Canada.

Guidelines on climate indices

WMO and ETCCDI produced a technical document enclosing "Guidelines on analysis of extremes in a changing climate in support of informed decisions for adaptation"WMO-TD No 1500, 2009 by Albert M.G. Klein Tank, Royal Netherlands Meteorological Institute Francis W. Zwiers and Xuebin Zhang, Environment Canada. The document addresses the overall question on how we should account for a changing climate when assessing and estimating extremes. Pertinent points include how to incorporate observed changes in extremes in the past in the analysis; and determining the best way to deal with available future climate model projections. A primary goal of this publication is to provide a set of guidelines to be used by the National Meteorological and Hydrological Services (NMHSs) around the world (NMHSs) for identifying and describing changes in extremes.

ETCCDI workshops - A tale for international collaboration

Promoting the analysis of extremes around the world by organizing regional climate-change workshops was recognized by the ETCCDI as an efficient mechanism for achieve international collaboration for monitoring climate extremes based on ETCCDI indices. World recognized experts in climate change have been actively involved in defining and guiding these workshops in various regions of the world based on hands-on-training workshops. The participants bring their long-term daily data, history about the observing stations to learn about quality control, homogeneity testing, and climate analysis.

Useful reference

Pamphlet of the Expert Team on Climate Change Detection and Indices (ETCCDI)

«WMO Statements on the Status of the Global Climate Climate data homogenization »