Analysis of daily rainfall concentration in northeastern Algeria 1980–2012

Abstract

This article analyzes the spatial distribution of the values of six daily precipitation concentration indexes in the northeastern part of Algeria. The used indexes were the concentration index (CI) and the Gini index (GI) with the resolution of precipitation amounts 1, 5, and 10 mm. The values of the six indexes are calculated for the period 1980–2012 with 22 stations, and on the other hand, the correlations of the CI1 concentration index with geographical and rainfall variables are analyzed. The values of CI1, CI5, and CI10 and IG1, IG5, and IG10 have been mapped using the tools of the ArcGis10.02 programs. The CI1 concentration index correlates significantly with all the geographic and rainfall variables considered. A negative linear correlation was observed with a linear correlation coefficient r = − 0.67 (p value = 0.0006) between CI1 and altitude. The correlation between CI1 and the distance to sea with a linear correlation coefficient r = − 0.47 (p value = 0.026), the correlation between CI1 and latitude is positive with r = + 0.40 (p value = 0.032). On the other hand, CI1 is significantly positively correlated with average annual precipitation, the coefficient of variation, and the number of rainy days in the same period: r = 0.52 (p value = 0.023); r = − 0.25 (p value = 0.049) and r = 0.49 (p value = 0.022), respectively.