Investigation and Analysis of 50-Year Trends of Rainfall Changes in Kashkan Poldokhtar basin during the Years 1969 to 2019
Elham kianisalmi
1
(
PhD student in watershed management, Faculty of Natural Resources, Lorestan University
)
Hossein Zeinivand
2
(
Associate Prof. Department of Watershed Management Engineering, Faculty of Natural Resources, Lorestan University
)
Naser Tahmasebipour
3
(
Associate Professor, Department of Watershed Management Engineering, Lorestan University
)
Keywords: Change Trend, Seasonal Precipitation, Rainfall Station, Confidence Level, Basin,
Abstract :
Precipitation is one of the most important meteorological variables which can impact on the occurrence of flooding. Analysis of precipitation provides useful information for planning water resources in the region. In this research, an investigation of the rainfall, in Kashkan Poldokhtar basin, has been carried out using a homogeneous daily rainfall dataset of 11 rainfall stations with 50 years of observation. The linear regression analysis,, 5-year moving average, anomaly, and Mann-Kendall (MK) trend detection were used to assess the variability and trends in rainfall. The results showed no significant trend was observed in the annual rainfall amounts over the basin, but increasing trends were observed in the seasonal rainfall amounts in some stations. The seasonal rainfall trends based on MK test showed significant changes at 5% confidence level at 3 stations in the autumn, 5 stations in the spring, and 6 stations in the summer and basin in the spring and summer seasons. The mean annual rainfall of 7 stations exhibited a well linear trend. The results showed that a significant decreasing trend was observed in the Kohdasht, Khorramabad-Chamanjir, Kashkan-Poldokhtar, and Sorkhab-Keshvar (outside basin) stations. The UF(k) and UB(k) curves in all stations had intersections which indicated that the rainfall has seen an abrupt. The analysis of sudden changes in rainfall is a suitable guide for water resources management, flood control and drought investigation in Kashkan-Poldokhtar basin.
1 Dang B L, Ren Z Y, Zhang C. Statistical analysis on precipitation in Xi’an region during the last 50 years. J. Northwest Uni. 2011(4) 1.139-144.
2 De Luıs, M Raventos J, Gonzalez-Hidalgo J.C. Sanchez, J.R. and Cortina, J. Spatial analysis of rainfall trends in the region of Valencia (east Spain). International Journal of Climatology.2000 20: 1451-1469.
3 Caloiero T, R Coscarelli, R, Gaudio, G. P. Leonardo. Precipitation trend and concentration in the Sardinia region. Theoretical and Applied Climatology. 2019: 297-307.
4 Duhan D, Pandey A. Statistical analysis of long term spatial and temporal trends of precipitation during 1901–2002 at Madhya Pradesh, India. Atmos. Res. 2013: 122, 136–149.
5 Sayemuzzama M, Jha M.K. Seasonal and annual precipitation time series trend analysis in North Carolina, United States. Atmospheric Research.2014:183-194.
6 Gedefaw Mohammed, Denghua Yan, Hao Wang Tianling Qin, Kun Wang. "Analysis of the Recent Trends of Two Climate Parameters over Two Eco-Regions of Ethiopia.2019: 161.
7 Xu Y, Xiaohou S, Xinyu M, Minhui L, Xiuneng L.Rongqi L. Variability and trend analysis of precipitation during 1961-2015 in Southwest Guizhou Autonomous Prefecture (SGAP), China. Journal of Agrometeorology. 2019 .21(1).31-35.
8 Baig Mirza Razi Imam. Spatio-temporal analysis of precipitation pattern and trend using standardized precipitation index and Mann–Kendall test in coastal Andhra Pradesh." Modeling Earth Systems and Environment. 2021: 1-20.
9 Kendall M. Rank Correlation Measures; Charles Griffin: London, UK.1975: 202.
10 Mann, H.B. Nonparametric Tests against Trend; Econometric Society: Cleveland, OH, USA. 1945.13. 245–259.
11 Zhang X, Li P. Li D spatiotemporal variations of precipitation in the southern part of the Heihe river basin (China). 1984–2014. Water. 2018: 10(4), 410.
12 Zhang Q, Sun P, Singh V.P, chen X. Spatial-temporal precipitation changes (1956–2000) and their implications for agriculture in China. Glob. Planet. Chang. 2012. 86–95.
13 Mo X.Y. Zhang Y, Qin Y, Huang X.X. Analysis of spatial-temporal variation of precipitation in the nanpan- beipan river basin. Yunnan Geog. Environ. Res.2012.24(1).7-11.
14 Soomro A.G, Babar M.M, Ashraf A, Memon A.The Relationship between Precipitation and Elevation of the Watershed in the Khirthar National Range. Mehran University Research Journal of Engineering and Technology.2019: 38(4).1067-1076.