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Investigating Differences between Modeled Historical and Station Calculated Drought
Citation:
Orejola, N., M. Nash, M. Mehaffey, AND A. Neale. Investigating Differences between Modeled Historical and Station Calculated Drought. US-IALE, Asheville, NC, April 03 - 07, 2016.
Impact/Purpose:
In this abstract, we investigate differences between modeled historical and station calculated drought. The information will be incorporated into the EnviroAtlas as a national stressor indicator of ecosystem service. The indicator is part of a national task milestone and EnviroAtlas tool deliverable.
Description:
With growing concern over increased frequency and intensity of extreme climate events, there is an imperative need to investigate drought under different future scenarios for the contiguous U.S. To assess future drought relative to a historical baseline, drought occurrence (number of events) and mean monthly drought duration can be calculated from a climatic water balance drought index such as the Standardized Precipitation-Evapotranspiration Index or SPEI at different time scales (6- and 12-month accumulations). However, in order to proceed with future drought interpretations, it is necessary to investigate the limitations of the modeled data by recognizing its differences with that calculated from station data. Thus, we calculated the two drought variables for 6- and 12-month SPEI from 1960-2005 for two datasets, the historical downscaled data NEX-DCP30 (modeled) and selected stations from U.S. Drought Risk Atlas (station). The differences between station and modeled drought showed that modeled compared reasonably well with station drought based on the minimal outliers (approx. 1-3.9% of 2,237 stations). The statistically significant clusterings of regions where modeled drought over/under predicted station calculated drought suggests similarities in spatial processes driving the differences across the contiguous U.S. Continuing research will investigate drought frequency and magnitude under different climate scenarios and the likely implications increased drought-related stress will have on vegetation, ecosystem services and human health.
