0000000000744215
AUTHOR
Sylvain Bigot
Cycles diurnes de rayonnement solaire et forets en Afrique Centrale.
The sunlightconditions prevailing in Central Africa, and their potential impact on forests traits and functioning, have neverbeen fully explored. Using satellite estimates documenting mostly the period 2005-2013, and accounting forscale interactions between the diurnal and annual cycles, we demonstrate that the seasonality of sunlight levelsstrongly vary across Central Africa forests. Gabon stands out with a main dry season strongly light-deficient,cool and moist. An original map of terra firme forest types developed by CIRAD shows that most of theevergreen forests of Central Africa develop in Gabon. We postulate that despite a mean annual precipitationamount below 2000 mm/yr, the Gabonese …
Rainfall variability in subequatorial America and Africa and relationships with the main sea-surface temperature modes (1951–1990)
The rainfall variability of subequatorial South America and Africa is poorly documented owing to the scarcity of data. We present a new land-only data set of monthly precipitation from 1951 to 1990, focusing on subequatorial South America and Africa, which improves the knowledge of rainfall variability and allows comparisons with GCM outputs. The results of multivariate analyses are compared with those performed on the best actual global rainfall data set developed by Mike Hulme. The main modes of bimonthly rainfall variability are not located in the major rain-forest basins of Za'ke and Amazonia, but rather on the tropical margins, such as Venezuela or Sudan, and near-coastal equatorial ar…
Evolution of dry season low cloud cover over the Atlantic coast of Central Africa from diurnal to interannual scale
Despite its bioclimatic importance, few studies have focused on the stratiform low-level cloud cover ofthe dry season (June-September) of the Atlantic coast of Central Africa. Using in-situ data documenting theperiod 1971-2019, we show that this cloud cover is underestimated by SAFNWC satellite observations andCMIP6 models. We identify three types of days: clear, cloudy at night and totally cloudy, the latterbeing more frequent on the coast and inland, to the windward of the Cristal and Chaillu Mountains. Onan interannual scale, temperature anomalies in the South Tropical Atlantic, the equatorial Pacific and theCongo Basin, by modulating the meridional and zonal circulation cells, influence…