Analyzing and Quantifying Rainfall Changes in Erbil Area 1992 – 2014 Using Standard Normal Period WMO-SNP

Abstract

Rainfall is one of the vital climatic factors that can indicate climate change. Spatial and temporal changes of rainfall would influence runoff, soil moisture and groundwater reserves. Analysis of precipitation trends is important in studying the impacts of climate change for water resources planning and management. The present study was conducted to determine changes in the annual and seasonal total rainfall over Erbil Area region in Iraqi Kurdistan Region using 23 years (1992-2014) monthly rainfall data at three rain-gauge stations, the widely used WMO 1961 – 1990 (61 – 90) standard normal period is compared to other consecutive 30-year normal periods in detail. The results indicated that a decreasing trend varied between 11.6 mm/year at Pirmam station and 10.8 mm/year at Erbil station, and 28.0 mm/year at Makhmur station. The presence of trend in annual and seasonal rainfall series determined by the widely used WMO 1961 – 1990 (61 – 90) standard normal period which is compared to other consecutive 23-year normal periods in detail and the analysis is being made of the seasonal and annual average of rainfall in the period (1992-2014) by analyzing their deviation from the average of the SNP (1961-1990) .