Journal of Agricultural Meteorology

Journal of Agricultural Meteorology

Investigating the changes in the frequency of low-intensity rainfalls and its relationship with the trend of rainfall and Standardized Precipitation Index in Kurdistan province

Document Type : Original Article

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Abstract
Changes in the intensity and frequency of rainfall in agricultural areas are one of the important consequences of climate change. An increase in low-intensity rainfalls (less than five mm/day) cannot play an effective role in providing the water requirement of rainfed agriculture and may lead to mistakes in planning for these areas. The main purpose of this study is to investigate the changes in the trend in the frequency of low-intensity rainfalls and its relationship with the trend of rainfall and Standardized Precipitation Index (SPI) in Kurdistan province, one of the important rainfed agricultural regions in Iran. For this purpose, the daily rainfall data of 30 years of four synoptic stations - Sanandaj, Bijar, Qorve, and Saqez were applied. After the homogeneity and trend test, the trend of seasonal and annual rainfall and drought parameters were calculated. Then, the rainfall data were separated into two groups with an intensity of less and more than 5 mm/day, and the frequency trend of each group was calculated. The results showed the decreasing and increasing trend of rainfall and drought, respectively, for all stations. The decrease in the intensity of rainfall has played a major role in the downward trend of rainfall. However, the decreasing trend of moderate to heavy rainfalls was observed in spring and winter, which is very important for rainfed agriculture. In addition, the frequency of low-intensity of rainfall has increased in Sanandaj and Qorveh stations. The intensity of drought in both stations was also higher than in others. In other words, the intensity of drought has a direct relationship with increasing the low-intensity rainfall frequency. These results show the importance of a more detailed investigation of rainfall parameters in the efficient planning of rainfed agriculture.
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Alijani, B., Mahmoudi, P., Chogan, A.J. 2012. Investigating the trend of annual and seasonal rainfall changes in Iran using the non-parametric method Sense slope estimator. Climatology Research, 3(9), 23-42. (In Farsi). ##Ashori, Z., Moalemi. M., Khodadadi. A., Torabinia. M. 2014. Climatic zonation planting sunflower cultivation in Kurdistan Province. International journal of Advanced Biological and Biomedical Research, 4(2), 243-247.##Bauer, P.J., Foulk, J.A., Gamble, G.R., Sadler, E.J., 2009. A comparison of two cotton cultivars differing in maturity for within-canopy fiber property variation. Crop Science, 49 (2), 651–657. ##Dargahian, F., Lotfinasab Asl, S. 2020. Temporal and spatial variations of precipitation trend in basins leading to Khuzestan province dust sources. Iran Nature, 5(3), 59-67. (In Farsi).##Gong, D. Y., Shi, P. J., Wang, J. A. 2004. Daily precipitation changes in the semi-arid region over northern China. Journal of Arid Environments, 59, 771-784.##Goswami, B.N., Venugopal, V., Sengupta, D., Madhusoodanan, M.S., Xavier, P.K. 2006. Increasing trend of extreme rain events over India in a warming environment. Science, 314(5804), 1442–1445.##Karl, T.R., Knight, R.W. 1998. Secular trends of precipitation amount, frequency, and intensity in the United States. Bulletin of the American Meteorological society, 79(2), 231-242.##Katiraei, PS., Hejam, S., Irannejad, P. 2007. The contribution of changes in the frequency and intensity of daily precipitation in the precipitation trend in Iran during the period from 1960 to 2001. Journal of Earth and Space Physics, 33(1), 67-83 (In Farsi).##Kistner, E., Kellner, O., Andresen, J., Todey, D., Morton, L.W. 2018. Vulnerability of specialty crops to short-term climatic variability and adaptation strategies in the midwestern USA. Climate Change, 146 (1-2), 145–158.##Lanzante, J. R. 1996. Resistant, roubust and nonparametric techniques for the analysis of climate data: theory and examples including applications to historical radiosond station data, International Journal of Climatology, 16, 1197-1226.##Maroufi, S., Tabari, H., Aeeni, A., Marofi, H. 2012. Investigating Temporal Trends and Spatial Characteristics of Rainfall and Meteorological Drought in the West of Iran during the Last Few Decades. Journal of Water Science Engineering, 1(3), 55-72. (In Farsi).##Masman, V., Castro, A., Fraile, R., Dessens, J. D., Sanchez, J. L. 2004, Detection of statistically significant trends in the summer precipitation of main land Spain. Atmosphric Research, 70, 43-53.##Mckee, T.B., Doesken, N. J.  Kleist, J. 1995. Drought monitoring with multiple time scales. Ninth Conference on Applied Climatology, American Meteorological Society, Jan 15-20, 1995, Dallas TX, pp. 233-236.##Mirzayi, Hasanlo, A., Abghari, H., Erfanian, M., Choobe, S. 2020. An Assessment of Spatial and Temporal Changes in Precipitation and Drought in Iranian Synoptic Stations of Iran. Watershed Management Research Journal, 33(4), 123-141. (In Farsi).## Mishra, A.K., Singh, V.P. 2010. A review of drought concepts. Journal of Hydrology, 391, 202–216. ##Mulhouse, J.M., Hallett, L.M., Collins, S.L. 2017. The influence of seasonal precipitation and grass competition on 20 years of forb dynamics in northern Chihuahuan Desert grassland. Vegetation Science, 28(2), 250–259.##Nazeri Tahrudi, M., Khalili, K., Ahmadi, F. 2016. Spatial and Regional Analysis of Precipitation Trend over Iran in the Last Half of Century. Water and Soil, 30(2), 643-654. (In Farsi).##Qaderi, N., Alijani, B., hejazizadeh, Z., saligheh, M. 2018. Spatial modeling of rainfed wheat yield using agroclimaticmicrozonation in Kurdistan. Journal of Applied researches in Geographical Sciences, 18(48), 1-19. (In Farsi).##Ramos, M. C. 2001. Raifall distribution patterns and their change over time in a Mediterranean area. Theoretical and Applied Climatology, 69, 163-170.##Ranjbar, A., Ebrahimipak, N.A.  Tafte, A. 2021. Investigating the trend of changes in the amount and frequency of low intensity rainfall in Kurdistan province. The 17th Iran Soil Science Congress and the 4th National Conference on Farm Water Management. Karaj. Iran (In Farsi).##Rockstrom, J., Karlberg, L., Wani, S.P., Barron, J., Hatibu, N., Oweis, T., Bruggeman, A., Farahani, J., Qiang, Z. 2010. Managing water in rainfed agriculture—The need for a paradigm shift. Agricultural Water Management, 97 (4), 543–550.##Pettit, A.N. 1979. A non-parametric approach to the change-point detection. Applied Statistics, 28(2), 126-135.##Sabziparvar, A., Torkaman, M., Merianji, Z. 2013. Water and Soil, 26(6), 1554-1567. (In Farsi).##Sala, O.E., Lauenroth, W.K. 1982. Small rainfall events: an ecological role in semiarid regions. Oecologia, 53 (3), 301–304.##Sohoulande, C.D., Stone, K., Szogi, A. Bauer, P. 2019. An investigation of seasonal precipitation patterns for rainfed agriculture in the Southeastern region of the United States. Agricultural Water Management, 223, 105728.##Vivekanandan, N. 2007. Analysis of Trend in Rainfall Using Non-Parametric Statistical Methods, international symposium on rainfall rate and radio wave propagation, American institute of physics, 101-113.##