Different types of rainy seasons in Tanzania
Classification of rainfall profiles
In order to achieve a classification of rainfall profiles, average rainfall
for each dekad, as for the first dekad of January, is computed in a first
step using the dekadal rainfall between 1983 and 2002. Subsequently,
ADDAPIX software is used again (see the
yearly classification
in the global analysis). After submitting the average dekadal series to
a principal component analysis a non hierarchical cluster analysis
followed. The purpose of reaching the higher level of synthesis without
loosing too much information resulted initially in 7 classes in Burkina Faso,
10 classes in Tanzania, 4 in Cambodia and 7 in Nepal. Finally, these
classes have been further revised to give the final classification. Country maps
(always Figure 1) show the spatial distribution of the defined rainfall
classes. Additional maps (always Figure 2) with the class profiles
are created to present the different types of rainy seasons.
Figure 1: Geographical distribution of the different types.
Figure 2: Average rainfall behaviour of each type of rainy season.
A number of locations (dots in Figure 1) have been selected as being
representative of the rainfall profile classes identified in order to
perform a risk analysis
including the calculation of the water satisfaction index (WSI), the actual
evapotranspiration (ETA), water surplus and water deficit.
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