The Variations in The Regions’ Boundaries of The Coefficient of Variations of Rains in Iraq

Abstract

This research paper is about an important aspect of rains in Iraq which is the coefficient of variations of rains in Iraq and it is considered a statistical scale expressed in percentage and used to specify the yearly fluctuation degree of rains. It is found out that the amount of rains become more fluctuating towards south and east of Iraq and it becomes less towards the northern parts. The general trend of coefficient of variations of rains in Iraq throughout 6 climatic cycles from the rainy season (1944-1945) to (2009-2010) has noticed an obvious raise. In the first climatic cycle, the coefficient variation was (%41); then it rose in the sixth climatic cycle into (%47.2) which was represented in the water years from (1989-1988) to water years (1998-1999). By representing the coefficient of variation results of rains on the map of Iraq throughout the six climatic cycles, five climatic categories appeared in the country, which are: intermediate, high, strong, very strong and extreme. The low and the very low coefficient of variations were not recorded in any climatic cycle. It appeared that extreme coefficient of variation region is always shown as a connected region which occupies the largest climatic region in the country as compared with the other categories. The widest extension of this region appeared in the fifth climatic cycle and covered more than three quarter of the country area. Among the six coefficients of variations categories of rains in Iraq, no important changes occurred in their regions, except the very strong coefficient of variation category, which its area decreased in the sixth climatic cycle after it was covering a large area in the second climatic cycle. In addition, all the studied stations had a noticeable decrease in the amount of rains in the last years.