Call for Participation: New GEWEX project “Short Time-Scale Precipitation Extremes”

In recent years a number of studies have investigated trends in subdaily precipitation extremes and their relationship with atmospheric warming. Results vary geographically, but in some cases show large increases in very short (hourly or less) precipitation extremes without similar changes in daily extremes. Few regions of the world have been investigated for these hourly changes to date.


The goal of the GEWEX Hydroclimatology Panel (GHP) Cross-Cutting Project on Short-Term Precipitation Events is to better characterize the global distribution and temporal trends in precipitation extremes at daily and shorter timescales, and their relationship to warming trends. The Project will also examine future changes in these extremes as projected by climate models (e.g., CMIP-5, CORDEX) to provide more robust knowledge of the global state of precipitation extremes, the relationship between daily and shorter time-scale extremes, and the potential changes due to global warming.

Principal research questions are:

                      What is the spatial distribution of observed precipitation extremes, and their trends, globally at daily time-scales and at sub-daily time-scales?

                      Are global and/or regional climate models able to simulate precipitation extremes at daily and sub-daily times-scales?

                      What are the projected future changes in daily and subdaily precipitation extremes due to global warming?

Addressing these questions will require significant effort in data collection and quality assurance, particularly, for subdaily data. The Integrated Surface Database (ISD; ) consists of global hourly and synoptic observations compiled from numerous sources. A gridded version of this data set, HadISD, is also being developed. However, most precipitation data only date back to the 1970s, and there are many quality issues and large areas of the world that remain uncovered. A variety of analysis techniques will be applied to the data to address the research questions.

Call for Participation

Researchers with access to daily and subdaily time-scale precipitation and other climate variables are encouraged to share their data with this project. This includes data collected as a part of a long-term observational facility or a short-term field experiment. All data collected will be subject to a common level of quality assurance and, where possible, will be made available to the research community through a suitable web portal.

A Data Analysis Working Group is being formed. If you have a novel data analysis idea and would like access to the data, contact Prof. Hayley Fowler (

Contributors: Hayley Fowler, Newcastle University, UK; Jason Evans, University of New South Wales (UNSW), Australia; Lisa Alexander, UNSW; Seth Westra, Adelaide University, Australia; Robert Dunn, Met Office, Hadley Centre, UK

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