Spatio-temporal analysis of precipitation pattern and trend using standardized precipitation index and Mann–Kendall test in coastal Andhra Pradesh

The most expedient means of analysing global climate change is to analyse the precipitation along with major components of the global atmospheric circulation. Like other Coastal areas, Coastal Andhra is also vulnerable to extreme weather events. So, in this study, the trend and pattern of the precipitation of the Coastal Andhra have been analyzed using daily and monthly rainfall data of 36 years (1983–2018). The standardized precipitation index, rainfall anomaly index and Mann–Kendall tests have been used to analyse the trend and pattern of precipitation. The result showed that the average annual rainfall was 161 cm in 1983 which first declined to 147 cm in 1991 but increased to 181 cm in 2001 and again declined rapidly to 91 cm in 2018. Apart from this normalized difference vegetation index (NDVI) has been used for the years 1983, 1991, 2001, 2011 and 2018 for the validation of dryness and wetness. The statistical analysis shows that rainfall in the study area shows a declining trend at the rate of − 1.27 cm per year as per the result obtained by the Sen, slope. Further, the association between mean annual rainfall and NDVI is found to be very strong with a higher positive value of the coefficient of determination.