Spatiotemporal analysis of long-term homogeneity, meteorological trend and drought variability over the semi-arid climatic region of Bihar, India (B-4391)

Abstract

The assessment of the spatiotemporal variability of meteorological parameters provides critical insights to identify emerging environmental risks posed by climate change. Such an evaluation can be helpful in obtaining strong evidence to explain the effect of climate change on crop yields and water resource management. The present study examined rainfall and drought characteristics in the semi-arid climatic region of Bihar. The dataset was acquired from the India Meteorological Department (IMD) dataset between 1970 and 2020 at a spatial scale of 0.25˚ × 0.25˚. Change point tests in the time series were divided into two periods: 1970–1990 and 1991-2020, with 1990 as the change point year. The Non-parametric Mann-Kendall test and Sen's slope were used to find the trend and estimate it at the significance level of 5%. The outcome showed that the northwestern, southwestern, and central districts of Bihar exhibited a negative trend, particularly in June, August, and September. The magnitude of decline ranges from -1 to -2 mm/year. The analysis shows an increasing trend in the total annual rainfall observed between 1970 and 2020. This pattern suggests that the methodological framework employed in this research can be effectively applied across different spatial scales and diverse geographic settings. The study provides a foundation for improved water resource management, climate adaptation planning, and strategies aimed at mitigating the potential impacts of extreme hydrological events.