Search results for "Afrique Centrale"
showing 5 items of 5 documents
État actuel des réseaux de mesures éco-climatiques en Afrique centrale : les ambitions du projet de recherche international FORGREENE.
2016
This work presents an overview of spatio-temporal quality andspatial density of rainfall networks of Cameroon, Gabon, Congo, CAP and DRC, particularly in the recentperiod (1973-2014) through the GSOD international database. Faced with enormous gaps observed, theseresults will help to select metrological and analytical orientations in FORGREENE project (Tropical forestsgreeness and cloudiness in Central Africa: present conditions and future evolution). A comparison with rainfallsatellite estimates (RFE type) also indicates their great potential, provided they are based on in situ validations.
Evolution of dry season low cloud cover over the Atlantic coast of Central Africa from diurnal to interannual scale
2022
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…
Analysis of cloudiness and solar radiation diurnal cycles for a better understanding of the forests greenness mean annual cycle in Central Africa.
2016
To better understand the Central Africa forests sensitivity toclimate variability, we jointly analyse the mean annual cycles of greenness, rainfall, cloudiness and solarradiation for the target region 0-5°N/12-19°E using high resolution satellite data. Our results demonstrate theimportance of the diurnal scale for understanding the mean annual cycles of rainfall, cloudiness and solarradiation and the way they shape those of forest greenness. They also suggest that whereas the March-Mayrainy season appears optimal for greenness especially because of favorable light conditions, water availabilityis the main controlling factor in December-January the main dry season and in February at the star…
Cycles diurnes de rayonnement solaire et forets en Afrique Centrale.
2018
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 …
Dyvalocca : un projet pour l'étude des nuages bas de saison sèche sur la façade atlantique de l'Afrique centrale et de leur impact bioclimatique sur …
2020
Low-level clouds are key components of the climate but are not well represented in weather and climate models. Recently it has been shown that an extensive low-level cloud cover develops during the June-September main dry season in western equatorial Africa, from the coastal plains of Gabon and Congo-Brazzaville to the inland plateaus downstream of the low-mountain crests. Such a cloudy main dry season is unique in the moist Tropics and is likely to explain the presence of the densest and evergreen forests of Central Africa as evapotranspiration is low and the quality of light is high. The ANR-DFG funded “DYVALOCCA” project will conduct from 2020 to 2022 a field campaign, raise existing in-…