Precipitation characteristics of easterly waves across the global tropics

Previous work has examined the development of TEWs and their associated precipitation for individual seasons or regional domains, but no studies exist that document the importance of TEW precipitation globally. This study quantifies the precipitation associated with TEWs across the entire tropics using satellite (Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement [IMERG]) and reanalysis (Modern-Era Retrospective analysis for Research and Applications, Version 2 [MERRA-2]) data.

Traditional space-time filtering of precipitation reveals a mostly similar climatological power distribution for westward traveling, synoptic period disturbances corresponding to TEWs within all data sets. Using objective tracking, we find that areas with maximum TEW frequency such as the North Atlantic, Equatorial Pacific, and Indian Ocean have the highest accumulation of TEW-associated precipitation. TEWs account for at most 30% of total annual precipitation in regions where they commonly occur and 1%-5% over much of the tropics.