Using monthly rainfall data to estimate rainfall erosivity factor of Iraq

Abstract

The erosivity factor have a major effect on soil therefor a lot off researchers are interested about it. Actually, the erosivity depend on rainfall that could be a main source to water which effect on soil. To understand the erosivity factor in Iraq, we attempt to explain erosivity factor throughout 30 years (1980– –2010). Because of daily data of interval 15 and 30 min are not provided in this area, we used the Fournier modifi ed index (MFI) that based on monthly date of rainfall. Also, we applied linear regression equation between annual rainfall and the MFI to predict the variables and coeff cient of determination was calculated. The study period divided to three decades and spatial distribution by Kriging method was used to interpolate the MFI of study area which calculate by ArcGIS 10.4.1. The results show that in the northern zone of Iraq MFI maximum values were recorded and in the range of MFI above 160. Moreover, in Emadiyah station the MFI excessed 250, which means the erosivity factor has a big effect on soil in this zone. Whereas, in middle zone, the MFI has range 0–120 but most of years of study period recorded 0–90 of the MFI. In southern zone, the MFI was 0–60 therefore the erosivity factor was moderated or law. The linear regression models were found for each station of study area and only Emadiyah, Teleafer, Khanqin and Nasiriya have weak coefficient determination.