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Interannual variability of African wave activity in a general circulation model
Author(s) -
Thorncroft C. D.,
Rowell D. P.
Publication year - 1998
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/(sici)1097-0088(1998100)18:12<1305::aid-joc281>3.0.co;2-n
Subject(s) - tropical wave , african easterly jet , climatology , homogeneous , atmospheric circulation , general circulation model , environmental science , atmospheric sciences , geology , climate change , tropical cyclone , oceanography , physics , thermodynamics
Abstract African easterly waves are an important part of the tropical climate, impacting on daily rainfall patterns as well as being the precursors for most Atlantic hurricanes. Despite their importance, the interannual variability of these waves is not well known or understood. This study shows that a general circulation model exhibiting a realistic amplitude of interannual seasonal mean rainfall variability in the tropical west African region, exhibits marked interannual variability in African easterly wave activity. Seasonal anomalies of this wave activity have been shown to be homogeneous over tropical north west Africa and are positively correlated with (i) the seasonal mean rainfall and associated convective heating in the Guinea Coastal region; and (ii) the strength of the easterlies in the region of and to the north of the African easterly jet. It is further concluded that the intraseasonal variations of African easterly jet instability must be considered for a more complete understanding of interannual African easterly wave variability. © 1998 Royal Meteorological Society