Analysis of Spatiotemporal Variations and Trends of Precipitation in Yazd Province by Asfezari Database During 1349 to 1394

Precipitation is one of the most important and variable elements of climate that has a lot of spatiotemporal variability, especially in arid and semi-arid regions. Adequate knowledge of precipitation variations is crucial for agricultural planning and water resource management in any region. For this purpose, in this study, using the daily data of Asfezari precipitation database during the period 1349 to 1394, the characteristics of precipitation and also the precipitation trends in Yazd province were investigated. The average coefficient of variation of the total annual rainfall of the province was 42.2 and varied from 32.9 to 68.4 in different cells. The highest coefficient of variation of precipitation on an annual scale was observed in the central and western regions of the province, which indicates the greater dispersion and risk of precipitation in these regions. The trend of precipitation was examined using nonparametric statistical tests of Mann-Kendall and Sen’s slope estimator. The spatiotemporal distribution of the trend of total annual Precipitation and total annual extreme Precipitation was similar and in both cases the general trend of the province was decreasing. The highest share of extreme Precipitation in total annual Precipitation was observed in the central regions of the province (Yazd-Ardakan plain). Therefore, in rainy years, these areas have favorable conditions for severe floods.