A seasonal air transport climatology for Kenya

A climatology of air transport to and from Kenya has been developed using k inematic trajectory modeling. Significant months for trajectory analysis ha ve been determined from a classification of synoptic circulation fields. Fi ve-point back and forward trajectory clusters to and from Kenya reveal that the transport corridors to Kenya are clearly bounded and well defined. Air reaching the country originates mainly from the Saharan region and northwe stern Indian Ocean of the Arabian Sea in the Northern Hemisphere and from t he Madagascan region of the Indian Ocean in the Southern Hemisphere. Transp ort from each of these source regions show distinctive annual cycles relate d to the northeasterly Asian monsoon and the southeasterly trade wind maxim um over Kenya in May. The Saharan transport in the lower troposphere is at a maximum when the subtropical high over northern Africa is strongly develo ped in the boreal winter. Air reaching Kenya between 700 and 500 hPa is mai nly from Sahara and northwest Indian Ocean in the months of January and Mar ch, which gives way to southwest Indian Ocean flow in Map and November. In contrast, air reaching Kenya at 400 hPa is mainly from southwest Indian Oce an in January and March, which is replaced by Saharan transport in May and November. Transport of air from Kenya is invariant, both spatially and temp orally, in the tropical easterlies to the Congo Basin and Atlantic Ocean in comparison to the transport to the country. Recirculation of air has also been observed but on a limited and often local scale and not to the extent reported in southern Africa.