Characterizing changes in US meteorological droughts based on NARCCAP simulations and copula-based severity-duration-frequency curves

Gridded precipitation data from 10 regional climate models within North American Regional Climate Change Assessment Program (NARCCAP) is analyzed to characterize the spatial distribution of droughts in the United Stated using the 6-month Standardized Precipitation Index (SPI) for historical (1968 -2000) and future (2040-2070) time periods. The bivariate drought frequency, specifically between severity and duration, is examined using a copula-based approach. In addition to drought severity-duration-frequency (S-D-F) relationships across the US, changes in the patterns of historical and future drought severity corresponding to different return periods are studied.