Document Type : Original Article
Authors
1
Department of Climatology and Geomorphology, Hakim Sabzevari University, Sabzevar, Iran
2
Department of Geography, Ferdowsi University of Mashhad, Mashhad, Iran
Abstract
The application of the RegCM4 dynamic model has enabled the study of mesoscale and regional scale atmospheric phenomena in different regions. Heavy precipitation is one of the essential atmospheric phenomena critical for agriculture in arid regions. Optimal use of rainwater increases water resources in the arid region. One of the solutions for optimal use of water in arid climate is to utilize crop pattern. The crop pattern means the share of cropping and selection of crops in an area, employing the optimal cropping pattern as one of the important solutions to water efficiency in agriculture. In this research, various data including rainfall data, NCEP/NCAR, TRMM satellite model, RegCM4 regional climate model, Aphrodite, and finally, agricultural data were used to change the cropping pattern for optimum use of water. Then, 5% precipitation threshold method was used to investigate heavy rainfall and selected as a representative of heavy rainfall in the study area on March 14th. The seasonal rainfall percentile chart, heavy rainfall maps and rainfall zones and performance of crops were then prepared and analyzed. The results indicate that the percentage of seasonal precipitation is in ascending and descending order in spring and winter, respectively. According to the regression model, Birjand, Nehbandan, and Ghayen stations are suitable in spring, and Ferdows and Boshrouyeh stations in winter. Moreover, the intensity of atmospheric streams in NCEP/NCAR and TRMM model maps gradually in northeast and east areas especially south Khorasan has led to heavy rainfall that RegCM4 model has been able to significantly simulate it and this rainfall has considerable values. Humidity values have increased on CAPE and thermodynamic graphs. Furthermore, in the zoning maps in the output of the observation map on Birjand station, Birjand, Ghayen, and Nehabandan, with the highest rainfall show better agricultural performance, while Boshrouyeh and Ferdows stations have the lowest performance. Therefore, since crop performance is directly related to rainfall, heavy rainfall can improve in agricultural in South Khorasan as a dry climate province. One way to deal with low-water resources in arid climates is to use crops such as Jujube, Barberry, and Saffron that are less water-intensive in agriculture and more adaptable to climate and regional conditions than other crops. Therefore, with proper use of rainwater during heavy rainfall in low-lying areas, the performance of agricultural products will greatly improve in South Khorasan province.
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