Projected 21st-century changes in the Central American mid-summer drought using statistically downscaled daily CMIP5 precipitation projections

Abstract:

The seasonal precipitation pattern of the Central American region is marked by a temporary reduction of precipitation during the typical May-October rainy season, often termed the mid-summer drought. A mid-summer drought (MSD) has been defined as a period of significant decrease in precipitation over a time period greater than one month. Different characteristics of the MSD, including the start date, duration, and intensity, have implications for regional ecosystems, crop production, and the livelihood of farmers in the region. The characteristics and driving mechanisms of the MSD have been investigated for many years, and recently an objective algorithm for the presence and intensity (or strength) of the MSD was developed based on monthly precipitation data. The current work develops an objective algorithm for MSD intensity and duration based on daily precipitation from a data set of gridded observations. The algorithm is then applied to future daily precipitation projections for the Central American region, produced by statistically downscaling climate model output produced as part of the 5th Coupled Model Intercomparison Project. This allows a representation of the projected changes in MSD at a finer temporal scale, and may help in shaping adaptation measures promoted to cope with these changes.