A 35-year meteorological drought analysis in the Caribbean Region: case study of the small island state of Trinidad and Tobago

Abstract

Small island states are vulnerable to changes in extreme weather events. In order to mitigate the effects of these events such as droughts, the understanding of the patterns of meteorological droughts is one of the first steps. This study aims to build a baseline scenario of meteorological droughts using the Standardized Precipitation Index (SPI) for the southernmost Caribbean islands of Trinidad and Tobago. Fourteen precipitation datasets, for the period 1980 to 2014, were analyzed to identify and assess temporal and spatial variations of droughts. The relevant SPI temporal intervals for the area are 2-M (Month), 5-M Dry and 7-M Wet corresponding to the dry and wet seasons and 12-M. Meteorological droughts were found to be heterogeneous in occurrence, magnitude, severity and frequency across Trinidad. Meteorological droughts were identified in the following years; for the 2-M, 1987 and 1989; for the long term, 12-M in 1993, 2001 and 2010; seasonally, for 5-M Dry, 2014 and for 7-M Wet, 2010. The observed decrease (increase) in frequency of dry events may have a positive (negative) effect on the Hollis (Navet) dam. Statistically significant trends were observed for the 12-M SPI with magnitudes ranging from − 0.06 to 0.04 per year and these were larger than the 2-M SPI trends, with changes between − 0.03 and 0.02 per year. For the first time, three areas of similar drought variability were identified for north and central Trinidad. These results highlight the variations of drought characteristics over a small island, the possible adverse effects on surface water reservoirs and provide impetus for more island specific studies.