4.7 GHCNDEX: Global Land-based Datasets for Monitoring Climatic Extremes

Tuesday, 8 January 2013: 5:00 PM
Room 15 (Austin Convention Center)
Imke Durre, NOAA/NESDIS/NCEI, Asheville, NC; and M. G. Donat, L. V. Alexander, and H. Yang

In this presentation, we will introduce GHCNDEX, an operationally updated, global gridded data set of climate extremes over land, and demonstrate its utility for monitoring the variations and trends in temperature and precipitation extremes. Based on the National Climatic Data Center's Global Historical Climatology Network - Daily dataset, GHCNDEX contains monthly and annual time series of 26 climate indices on a 2.5° latitude by 2.5° longitude grid for the period 1951-present. The climate indices are recommended by the World Meteorological Organization's Expert Team on Climate Change Detection and Indices and characterize the intensity, duration or frequency of various climate events that have a direct impact on society.

Consistent with other observational data sets, the temperature related climate indices in GHCNDEX indicate warming trends during the past 60 years over most of the land areas covered by the data, with generally stronger increases in minimum temperature than in maximum temperature. Most significantly, the frequency of cold nights (i.e., the annual number of days on which daily minimum temperature is below its local 10th percentile (TN10p)) is found to have decreased significantly. Changes in precipitation extremes (e.g., the annual maximum five-day precipitation total (Rx5day)) are spatially less consistent than trends in temperature indices, with increases in some regions and decreases in others.

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