Examining the spatiotemporal characteristics of droughts in the Caribbean using the standardized precipitation index (SPI)

Extreme droughts have affected the Caribbean over recent decades. Although the connections of droughts with climate variability and change have been examined, the spatiotemporal and areal extent characteristics of rainfall anomalies during drier than normal periods have not been analyzed thoroughly. Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) data were used to extract the standardized precipitation index (SPI) for 2 seasons, May-July (MJJ) and August-October (ASO) for the 1981-2018 period. SPI data were classified into 7 groups: extremely dry (SPI <-2), severely dry (-2 to -1.5), moderately dry (-1.5 to -1) near normal (-1 to 1), moderately wet (1 to 1.5), severely wet (1.5 to 2) and extremely wet (>2). The most extreme droughts were identified for the Greater Antilles region and each island individually, the areal extent of each drought period was calculated, and the areas affected by multiple severe-extreme periods were identified. The 2009 ASO period had the largest area (>70%) under moderate, severe or extreme drought, mostly in Hispaniola, eastern Jamaica and eastern and western Cuba. The 2015 MJJ drought was identified as the period with the second-largest area under extremely dry conditions (23.3%), with western Hispaniola identified as the most strongly affected area. The 1986 ASO meteorological drought period was identified as the driest period with the largest area classified as experiencing extreme drought (24.26%). Some areas in the Greater Antilles experienced 7 or more extreme drought periods, with eastern Cuba, northern Jamaica, northwestern Hispaniola and eastern Puerto Rico being the most affected regions.