Changes in the means of temperatures and rainfall of the period 1981-2010 with respect to mean values of 1951-80 over the Indian stations

Abstract

In this paper, the changes in monthly and annual means of maximum temperature, minimum temperature and rainfall at well distributed 178 stations of India for the period 1981-2010 as compared to the respective means of 1951-80, are determined and analysed. To test the significant differences at the station, Student’s t test has been applied.

Increasing trend in monthly and annual mean maximum temperature is found at most places of southern and western regions of India. There is a decrease in maximum temperature in Indo-Gangetic Plains (IGP) region in January to June months. Significant rise in maximum temperature in all months except August is found at more places in southern part (south of 20° N) of India than northern part(north of 20° N). Significant fall in the temperature is found at a few places of the country. The same trend is found in annual maximum temperature. Minimum temperature has increased at most places of the country in all months except April to June where in it decreased over northern, central and eastern regions. During November to March months, minimum temperature increased more at most places of northern part of the country. Annual minimum temperature has increased at most places of the country except over UK, Significant fall in minimum temperature is observed at some places of the country.

There is a less change in monthly rainfall all over the country. Annual rainfall slightly decreased at most places of the country except Meghalaya, WB and Kerala where it increased. There is a significant fall in annual rainfall at some places of the country.