Scientific evaluation of the tropical rainforests resources in Africa using field investigation and satellite data

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This research was performed focusing on field investigations over the tropical rainforest region in Africa, especially the Zaire River Basin, so as to create a scientific ecoclimatological database for the analysis of the seasonal, inter-annual and long-term changes in both the rainforest ecosystem and the climatological parameters (rainfall, temperature, vegatation cover, etc.) over this region.Suffices to point here the main new findings from our analyzes over this tropical rainforest region and the surrounding savanna woodland and grassland areas : 1. The existence of a remarkable 2-to 5-year oscillation in the temperature data, with strong positive correlationship with the Southern Oscillation Index (SOI), and therefore the ENSO.2. An omnipresent quasi-decadal oscillation (QDO) in the temperature, humidity and rainfalls records, with a periodicity matching that of the solar activity (sunspot numbers). 3. A persistent warming trend observed at all the stations in Zaire, with a mean increase of 0.5 to 1.5ﾟC over the 1960-90 period : this is more than the values observed for the global warming on the same 30-year period. 4. For every analyzed point, a strong desiccation trend, manifested by a strong decrease in rainfalls as well as the lengthening of the dry season (up to 3 months at some stations). 5. The magnitude of these long term trends (warming and desiccation) suggests that these phenomena are regional and imbedded in the change in the local ecoclimatological conditions. The remarkable relationship between these changes and the local people's lifestyle and alteration of the environment for their living (shifting cultivation, bushfire, fuel wood, etc.) has been highlighted.