Results and Discussions
Annual Trend of All India Temperatures
The all India annual mean, maximum, and minimum temperature series are shown in Fig. 2. A significant increasing trend of 0.6 °C per 100 years is observed in the all India annual mean temperatures for the period 1901-2010. It may be seen that the annual maximum temperature rose consistently over the data period and rate of increase is 1.0 °C per 100 years for the period 1901-2010. Similarly, in the annual minimum temperature series, a significant increasing trend of 0.18 °C per 100 years for the period 1901-2010 is noticed. We may observe that the minimum temperatures did not witness any significant rise over most of the data period except during the recent few decades. Therefore, the rise in annual mean temperatures is primarily contributed by the increase in maximum temperatures. These trends are statistically significant at the 95 % confidence level.
From Fig. 2, we may also observe that the rate of warming as 0.18 °C per decade. Thus, although maximum temperatures increased gradually and consistently over the entire period, the rate of rise during the past 30 years was almost double. It may also be seen that rise in minimum temperatures was very spectacular for the period 1981-2010 as annual minimum temperatures (which was practically trendless till 1980) increased at the rate of 0.17 °C per decade.