Evolution and regionalization of precipitation in northern Algeria (1936-2009)

An analysis of the rainfall of northern Algeria has been undertaken for a period of 73 years (1936-2009). One hundred and two (102) rainfall time series were selected and submitted to five statistical tests to detect a trend or break point. A significant downward trend is observed since the mid-1970s, particularly in the west of the region (rainfall deficit ranges from 16 to 43%). The standardized precipitation index showed that the decades of 1980 and 1990 were the most deficient. These results correspond generally to the rupture detected in Morocco. A regionalization of precipitation using principal component analysis highlighted six homogenous regions. This spatial distribution shows the vulnerability of each region to climate change.