In this study, the spatial variation of daily and monthly concentration
precipitation index and its aggressive-ness were used in 23 rainfall
stations in the extreme north-east of Algeria over the period 1970–2010.
The trend was analysed by the Mann–Kendall (MK) test. The results show
that daily precipitation concentration index (CI) values are noticeably
higher in places where the amount of total precipitation is low, the
results of MK test show that areas of high precipitation concentration
tend to increase. The seasonality and aggressiveness of precipita-tion
are high in the eastern and western parts of the study region (eastern
and central coastal of Constantine catchments), whereas a moderately
seasonal distribution with low aggressiveness is found in the middle of
the study area (plains and central Seybouse catchment). As a result, the
modified Fournier index (MFI) has a signifi-cant correlation with annual
precipitation, whereas the CI and monthly precipitation concentration
index (PCI) show an opposite correlation in relation to annual
precipitation.