4.2 Climate severity

 

Rainfall severity indices are derived by considering all observations which are less than 25% (first quartile) of the ranked historical records to be dry while those which are more than 75% (third quartile) are considered wet.

Figure 2 shows the spatial pattern of the rainfall severity index for the GHA sub-region during August 2009. Near normal to wet conditions were recorded over the western, southwestern and central parts of the northern sector as well as the western parts of the equatorial sector. Much of the southern and equatorial sectors experienced generally dry conditions.

 

 

Figure 2: Rainfall severity index for August 2009 (Indice de rigueur de la sécheresse pour le mois d'août 2009)

 

 4.2.1 Cumulative climate stress severity monitoring

The extent of climate-related impacts on any particular system depends on the severity and duration of the climate stress. The cumulative climate stress severity has direct and indirect severe impacts on livestock, food security, water resources, health and many other socio-economic sectors. The cumulative rainfall performance for some selected stations in the GHA sub-region for the January to August 2009 period is shown by Figures 3a and 3b. Below normal rainfall conditions were experienced over parts of the northern and equatorial sectors (Figure 3a and 3b) during this period

 

 

Figure 3a: Cumulative rainfall series for selected stations (séries de pluviométrie cumulée pour des stations sélectionnées)

Figure 3b: Cumulative rainfall series for selected stations (séries de pluviométrie cumulée pour des stations sélectionnées)