Assessing the Characterization of Climate Variability: Case of Watershed Medjerda (North East of Algeria)

Several recent climatic events large-scale have pushed the global community to take an interest in
climate change and their impact on resources in water. Among them, we can cite drought which
affected the Maghreb countries, Algeria in particular since the 1970s. This study has the advantage of
some statistical methods to interpret the spatiotemporal variability of precipitation sixteen rainfall
stations located in the watershed of Medjerda (North East of Algeria) on a period ranging from 19 to
38 years. Whilst analyzing such series, there was an observed break in the period 1980 and 1990.
Thus, the results of the mapping of interannual rainfall indices calculated per decade over the period
1971- 2007 shows the decades 80 and 90 appear as deficit throughout the territory of the basin. Thus,
a trend to a return of precipitation is noted for the period (2001-2007). At the monthly scale,
precipitation increased significantly after years of failure for the winter months and spring, with the
exception of March. An exceptional concentration of rainfall in the month of August is observed. At the
daily scale, the analysis of daily rainfall fractions shows a trend of increase in the average
annual rains total of more than 20 mm after years of failure. The Medjerda basin has also known a
reduced rainfall and an increase in temperature over a period ranging from (1913-1938) to (1969-
2007).