On the Precipitation Trends in Global Major Metropolitan Cities under Extreme Climatic Conditions: An Analysis of Shifting Patterns

Abstract

On a local and regional level, climate change has had a significant impact on precipitation in the global climatic state. The purpose of this research is to examine the trend and character of urban precipitation in the world’s most densely inhabited metropolis. From 1981 to 2020, 40 years of monthly and annual precipitation data from 50 major metropolitan cities throughout the world, based on population statistics, were analysed. The monthly and annual precipitation analysis was done using a homogeneity test, shifting point test, non-parametric Modified Mann Kendall test, and also through computing the magnitude of the trend using Sen’s slope estimate. According to the findings of the study, the most homogeneous data was obtained in May (90 %) and the least in September (74%). In 2002, the highest number of breakpoints were found in July (9 cities) and August (8 cities). The month of January has the largest significant positive trend (10 cities) whereas annually it has 20 cities. The monthly maximum of the significant negative trend was discovered in February (4 cities) and annually in 2 main cities. In November, the maximum positive and minimum positive Sen’s slope values were found to be 82% and 56%, respectively. The findings of this study are important for future water resource projections, flood or drought predictions, and engineering, scientific, industrial, agricultural, and social studies. The goal of this research is to come up with a good plan for dealing with urban flash floods and droughts as precipitation acts as the key parameter of the hydrological cycle.