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Land surface feedbacks and palaeomonsoons in northern Africa
Author(s) -
Broström A.,
Coe M.,
Harrison S. P.,
Gallimore R.,
Kutzbach J. E.,
Foley J.,
Prentice I. C.,
Behling P.
Publication year - 1998
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 - 10.1029/98gl02804
Subject(s) - monsoon , orbital forcing , biome , wetland , forcing (mathematics) , precipitation , climatology , vegetation (pathology) , albedo (alchemy) , environmental science , geology , climate model , grassland , climate change , ecosystem , oceanography , geography , meteorology , medicine , art , ecology , insolation , pathology , performance art , agronomy , biology , art history
We ran a sequence of climate model experiments for 6000 years ago, with land‐surface conditions based on a realistic map of palaeovegetation, lakes and wetlands, to quantify the effects of land‐surface feedbacks in the Saharan region. Vegetation‐induced albedo and moisture flux changes produced year‐round warming, forced the monsoon to 17°–25°N two months earlier, and shifted the precipitation belt ≈300 km northwards compared to the effects of orbital forcing alone. The addition of lakes and wetlands produced localised changes in evaporation and precipitation, but caused no further extension of the monsoon belt. Diagnostic analyses with biome and continental hydrology models showed that the combined land‐surface feedbacks, although substantial, could neither maintain grassland as far north as observed (≈26°N) nor maintain Lake “MegaChad” (330,000 km²).