Regional level long-term rainfall variability assessment using Mann-Kendall test over the Odisha state of India

The climatic variability severely affects the environment, water availability, agriculture, food security, etc. particularly in the developing countries like India.In India rainfed agriculture covered about 68 per cent of the total cultivated area and more than 40 per cent of human and 60 per cent of livestock population (Sharma and Soni, 2006). The gridded rainfall data procured from Indian Meteorological Department (IMD) Pune with the resolution of 0.25o latitude x 0.25o longitude has been used in this study.The long-term (1901-2013) annual average rainfall of state of Odisha is approximately 1438 mm.The average weighted monthly rainfall for each district have been estimated according to the number of grids lies inside the boundary of each district.The whole year is categorized into different seasons mainly: winter season rainfall (December-February), pre-monsoon rainfall (March-May), monsoon rainfall (June-September), and post-monsoon rainfall (October-November), for investigating the spatial and temporal changes in rainfall. The Mann Kendall (MK) test, a non-parametric test is considered as better than other parametric tests for detection of monotonic rainfall trends in time series data.