40 Years of Surface Air Temperature Trend of Madurai City, Tamil Nadu, India

Surface air temperature data of Madurai city, Tamil Nadu state, India were analyzed using statistical techniques to demark the signs of climate change. Seasonal and annual trends were analyzed for the 1961-2000 period surface air temperature data of Madurai city and the distinct temporal distribution of the temperature was found from the study. The trends of Tmax (maximum temperature), Tmin (minimum temperature) and TM (Mean Temperature) were plotted and compared. The average annual temperatures of Tmax, Tmin and TM have raised 0.080C, 0.60C and 10C respectively. Summer average temperature raised 20C and other seasons have also got 10C temperature rise in 40years. The confidences were computed for to identify the temperature trend of Madurai city. The confidence values are positive and imply the warming of surface air temperature. The trends of annual and seasonal temperatures and confidence were compared for two periods: 1961-1980 & 1981-2000 to identify the pattern of temperature trend in Less Urbanized Period (LUP) and More Urbanized Period (MUP). The positive correlation with urbanization of temperature was noticed from the study. The Diurnal Temperature Range (DTR) also evaluated and the results support the warming effects of the surface air temperature in Madurai city in recent years.