Summary
Rainfall in West Africa is examined in relation to monthly mean equivalent potential temperature (θ e )at the earth's surface. The study revealed that monthly mean equivalent potential temperature (θ e ) and monthly rainfall (R) generally decreased northwards from the equator.
A good relationship existed betweenR andθ e in the northern zone of West Africa (i.e., north of 7.5° N). No definite relationship existed in the southern zone. In the northern zone, the departure ofθ e from its annual mean (\(\bar \theta _e\)) first became positive about a month before the onset of the rains. Positive departures from\(\bar \theta _e\)) generally resulted in more than normal (or average) rainfall in this zone. In general, little or no rainfall occurred in West Africa wheneverθ e was less than 320 K.
Zusammenfassung
Der Niederschlag (MonatssummeR) in Westafrika wird in Zusammenhang mit der mittleren monatlichen Äquivalent-temperatur (θ e ) an der Erdoberfläche untersucht. Es zeigte sich, daß die Monatswerte beider Elemente im allgemeinen vom Äquator nach Norden abnehmen.
ZwischenR undθ e ergab sich für das nördliche Westafrika (nördlich von 7.5° N) eine gute, für die südliche Zone jedoch keine beweisbare Übereinstimmung. In der nördlichen Zone übertrafθ e das Jahresmittel erstmals etwa einen Monat vor Beginn der Regenzeit. Positive Abweichungen vom mittlerenθ e hatten immer übernormalen Niederschlag in dieser Zone zur Folge. Dagegen gab es wenig oder keinen Niederschlag in Westafrika, wennθ e unter 320 K lag.
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Oduro-Afriyie, K. On the mean monthly equivalent potential temperature and rainfall in West Africa. Theor Appl Climatol 39, 188–193 (1989). https://doi.org/10.1007/BF00867946
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DOI: https://doi.org/10.1007/BF00867946