Where Does the Moisture for North Atlantic Tropical Cyclones Come From?

Abstract

In this study, we identified the origin of the moisture associated with the tropical cyclones’ (TCs) precipitation in the North Atlantic Ocean basin during their three well-differentiated life stages between 1980 and 2018. The HURDAT2 database was used to detect the location of 598 TCs during their genesis, maximum intensification peak, and dissipation phases. The global outputs of the Lagrangian FLEXPART model were then used to determine the moisture sources. Using a k-means cluster analysis technique, seven different regions were identified as the most common locations for the genesis and maximum intensity of the TC phases, while six regions were found for the dissipation points. Our results showed that the origin of moisture precipitating was not entirely local over the areas of TC occurrence. The North Atlantic Ocean to the north of the intertropical convergence zone at 10°N (NATL)—especially from tropical latitudes, the Caribbean Sea, and the Gulf of Mexico—provides most of the moisture for TCs (∼87%). The Atlantic Ocean basin southward of the ITCZ (SATL) played a nonnegligible role (∼11%), with its contribution being most pronounced during the TC genesis phase, while the eastern tropical Pacific Ocean made the smallest contribution (∼2%). The moisture supported by TCs varied depending on their category, being higher for hurricanes than for major hurricanes or tropical storms. Additionally, the approach permitted the estimation of the mean residence time of the water vapor uptake that produces the precipitation during TC activity, which ranged between 2.6 and 2.9 days.