Title: Rainfall trend analysis in Gujarat's semi-arid zone: a modified approach with autocorrelation consideration

Authors: Ramiz F. Tasiya; Naveena K. Kannegowda; Shilpesh C. Rana

Addresses: Civil Engineering Department, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara, India ' Land and Water Management Research Group, Centre for Water Resources Development and Management, Kunnamangalam, Kozhikode, Kerala, India ' Civil Engineering Department, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara, India

Abstract: Precise identification of rainfall movement is very essential during climate change scenarios for better water resources management. Erratic and violent monsoon rainfall movements are observed in the coastal region of Maharashtra, Gujarat, and Kerala within a very short period. The aim of the research is to identify the changes that occurred in the South-West monsoon rainfall trend using advance statistical package of R-software, for the semi-arid region of Gujarat. From the Wallis and Moore phase-frequency test, it is found that 6 out of 29 stations are having significant autocorrelation. Modified Mann-Kendall and Sen's slope tests are used to carry out rainfall trend analysis. Spatial representation of mean SW-monsoon rainfall and Sen's slope shows lower magnitude near coastal region and higher magnitude at higher elevation range. As a result, it is concluded that in monsoon two stations (7%) and particularly during June month seven (24%) stations are showing a significantly decreasing trend.

Keywords: R-software; Sen's Slope test; Wallis and Moore phase-frequency test (Z- test); modified Mann-Kendall test.

DOI: 10.1504/IJHST.2024.140315

International Journal of Hydrology Science and Technology, 2024 Vol.18 No.2, pp.211 - 235

Received: 02 Sep 2022
Accepted: 22 Apr 2023
Published online: 02 Aug 2024 *

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