Assessment of rainfall trend and variability of semi-arid regions of Upper and Middle Godavari basin, India

Abstract

Study of rainfall pattern and trend in the long term is essential from climatic change and socioeconomic perspectives. In the present study, monthly, seasonal and annual rainfall of semi-arid regions (Madhya Maharashtra, Marahwada and Vidarbha) of the Godavari basin is evaluated for the period of 1871–2016. The innovative trend analysis (ITA), Mann–Kendall test (MK) and Sen's slope estimator methods are used to check gradual change. A significant increasing or decreasing trend is not detected in the seasonal and annual rainfall series for any of the regions. The rainfall variability index indicates Madhya Maharashtra has received normal rainfall for 40% of the time, Marathwada for 36% of the time and Vidarbha region for 41% of the time. Very dry and very wet conditions are experienced by all three regions for 15% of the time. The spatial and temporal variation in the seasonal and annual rainfall is not significant in these regions. The results obtained from the study will be useful for water resource management of the Godavari basin. HIGHLIGHTS Increasing trend in rainfall of August and decreasing trend in September is observed for all the regions.; Significant upward or downward trend is not found for any season and for annual rainfall.; All the regions receives the normal rainfall for 39% of the time.; All the regions experiences very dry and very wet situation for 15% of time.; The results are matching with the rainfall trend for all India.;

Keywords

• godavari basin
• innovative trend method
• mann–kendall test
• rainfall
• sen's slope estimator
• trend