Atmospheric Freshwater Transport From the Atlantic to the Pacific Ocean: A Lagrangian Analysis

Abstract

AbstractThe Atlantic‐to‐Pacific atmospheric freshwater transport was calculated using Lagrangian water mass trajectories. These were decomposed into eastward and westward moving classes, carrying water over Afro‐Eurasia and over America, respectively. The results reveal that the midlatitude westerlies are contributing to midlatitude precipitation in the Pacific Ocean through transporting water mass from the midlatitude Atlantic Ocean over Afro‐Eurasia. In addition, precipitation in the Eastern Tropical Pacific Ocean is found to be associated with the easterly winds carrying water mass from the tropical Atlantic Ocean. A quantitative analysis of the atmospheric freshwater transport furthermore shows that annually, the westerlies carry 0.40 Sv, approximately twice as much water as the easterly trade winds (0.26 Sv) to the Pacific Ocean, but with a strong seasonality. The Atlantic Ocean exports more freshwater across Afro‐Eurasia than across America, except during the June–August periods. The average residence time of this atmospheric water transport is roughly twice as long when it crosses Afro‐Eurasia (54 days) rather than America (24 days).