Long term Observing Period (LOP) and instruments

Given the great variability of climatic conditions from year to year, observations are needed over several annual cycles in order to gain a proper vision of the diversity of the seasonal cycles, around a mean state which is only a statistical concept, but is never observed as such. The operational networks are precisely intended at this type of monitoring. However, operational networks are not dense enough to sample properly the spatial scales of interest when studying the links between the climate, the water cycle and the vegetation dynamics at the intrasesonal scales. Rainfall for instance has been shown to be extremely variable in space over the Sahel with characteristics scales in the order of 20-30 km, event when considering accumulation over the whole rainy season. It stems from this that the operational networks cannot sample the great variability of the seasonal rainfields and that the global rainfall indices supposed to characterise the rainy season are giving an oversimplified image of what the rainy season is. For this decadal scale AMMA is thus relying on specific observing systems that do not cover the whole region but provide a sampling of the main eco-climatic conditions encountered in West Africa.

AMMA LOP List of Instruments (+ Specific Campaigns)