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Revisiting the connection between African Easterly Waves and Atlantic tropical cyclogenesis
Author(s) -
Russell James O.,
Aiyyer Anantha,
White Joshua D.,
Hannah Walter
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071236
Subject(s) - tropical cyclogenesis , tropical cyclone , tropical wave , african easterly jet , climatology , atlantic hurricane , cyclogenesis , troposphere , storm , geology , storm track , environmental science , atmospheric sciences , oceanography , cyclone (programming language) , field programmable gate array , computer science , computer hardware
African Easterly Waves (AEWs) are the primary precursor for Atlantic tropical cyclones (TCs). We update the statistics on this relationship using reports from the U.S. National Hurricane Center. Sixty‐one percent of TCs originate directly from AEWs. Indirectly, AEWs are implicated in the formation of an additional 11% of TCs. AEW activity is quantified by eddy kinetic energy (EKE). The correlation between seasonal mean EKE and TC genesis is maximized in the lower troposphere below the southern AEW storm track, instead of where the canonical AEW is maximized. Therefore, midlevel AEW activity is a poor predictor of TC genesis, whereas its lower tropospheric circulation exerts stronger control. In most seasons, AEW activity is supercritical, and therefore, EKE is only a controlling factor in seasons when the low‐level EKE is weak. Predicting 1000–800 hPa EKE below the southern AEW track may be useful for seasonal TC prediction.