Unraveling Precipitation Trends and Variability under the Influence of Climate Change in the Navsari District of Gujarat

Abstract

Studying the variability of rainfall holds significant importance in the dominion of agriculture. To facilitate the optimal planting of crops in the face of climate fluctuations, agro-meteorologists predominantly depend on rainfall distributions. These distributions serve as a crucial tool for understanding the rainfall patterns within a specific area. This study undertakes a thorough examination of precipitation trends in the Navsari district of Gujarat, spanning the years 1983 to 2022 under the influence of climate change. The study utilized descriptive statistics to assess the characteristics of rainfall, while the Mann-Kendall test is utilized to determine the trend in rainfall patterns. Additionally, the Standard Precipitation Index (SPI) is calculated to quantify the degree of wetness in the region. It was observed that over the four decades, Navsari witnessed an annual mean rainfall of 1662.59 mm, accompanied by a standard deviation of 475.73 mm and a Coefficient of Variation (CV) of 28.61%, indicating notable inconsistency in annual rainfall. Onset delays were observed in five years, with notable delays in 1986, 1992, and 2005. Withdrawal delays occurred in seventeen years, ranging from 7 to more than 15 days. The normal monsoon duration of 111 days was exceeded in fourteen years but curtailed in twenty-six years, with 1996 experiencing the highest and 1986 the lowest monsoon days. Additionally, in the last decade, a noticeable increase in very wet months was observed. Season-wise SPI analysis identified extreme wet conditions in post-monsoon (1983, 1999), winter (1994, 2014), and pre-monsoon seasons.