SPATIAL VARIATION OF AIR TEMPERATURE AND TREND DETECTION USING NON-PARAMETRIC ANALYSIS FOR TAMIL NADU

Abstract

Assessment of spatiotemporal dynamics of meteorological variables is essential in the context of climate change. Maximum and minimum temperature data on a monthly scale of 30 years (1991-2020) were used to determine the possible changes in air temperature. The Mann-Kendall (MK) trend test is a nonparametric, rank-based approach identifying significant monotonic trends in meteorological and hydrological data. The spatial variation of maximum temperature revealed that out of 38 districts studied, more than 35°C was observed in 12 districts during March, 23 districts during April, 27 districts during May, 20 districts during June, nine districts during July and three districts during August respectively. Higher minimum temperature of more than 27 °C was observed during April (3 districts), May (16 districts), June (12 districts), July and August (3 districts each) and September (2 districts) respectively. The rate of increase in temperature will eventually affect the crop production and agricultural activities. Notably, during December, minimum temperature exhibited an  increasing trend  @ 0.12°C/year at Krishnagiri followed by 0.11°C /year each in Dharmapuri, Dindigul, Namakkal and Salem districts of Tamil Nadu. The crops raised during rabi season in these districts may face terminal heat stress in achieving high productivity of the crops.