Influence of SSTs Changes on the Caribbean Low Level Jet and Moisture Transport Variability in the Intra-Americas Region

The Intra-Americas Region (IAR), the geographical region that includes the Caribbean, Mexico, Central America and parts of North and South America, is sensitive to climate changes. Given its importance as a moisture transport to the North American continent, its study is necessary. However, the mechanisms that drive the varying climate trends in this area have yet to be fully characterized. Previous research has studied the drivers that potentially contribute to the complexity and variability of climate in this region. Among them are the Caribbean Low Level Jet (CLLJ), identified as a 925-hPa zonal wind region, and the Atlantic Warm Pool (AWP), a large body of warm water that appears in the Gulf of Mexico, the Caribbean Sea, and the western part of the tropical North Atlantic (Wang, et.al). The North Atlantic Subtropical High (NASH), located at the northeastern side of the AWP, produces easterly trade winds and transports moisture that enter the Caribbean Sea via the CLLJ. These past studies identified that the CLLJ is maximized in the summer and winter and has correlations with SSTs and vertical wind shear, both key variables for Atlantic hurricane activity. Other reports indicate possible intensification of CLLJ and increase in moisture content in the Caribbean low atmosphere in the early rainfall season (Comarazamy and Gonzalez, 2012). This paper focuses on analyzing CLLJ changes over the years 1982-2012 and possible correlations with SST, moisture transport, and precipitation within that time period. The methodology used for the study presented here includes analysis of historical climate trends in the IAR using surface station data, SST datasets, and large-scale vertical gridded atmospheric data (NCEP). The SST data used here is a daily, 0.25° resolution National Oceanic Atmospheric Administration (NOAA) product. This analysis leads to identifying the presence of trends related to CLLJ dynamics and associated moisture transport and precipitation patterns across the region.