Spatial and Temporal Trends in High Resolution Gridded Temperature Data over India

摘要

The changing temperature, directly and indirectly, has significant effect on the agricultural production and economy of the country which necessitates detailed study of the spatial and temporal variability of temperature. This paper focuses on the spatio-temporal trend analysis of minimum and maximum temperature over India. Daily gridded temperature data with spatial resolution of 1 degrees x 1 degrees for the period of 1969-2005 were analysed using Mann-Kendall (MK) non-parametric test at 3 levels of significances, namely, 1%, 5%, and 10%. The diurnal temperature range was also analysed. Results showed that maximum temperature experienced significant decreasing trends in the entire Indo-Gangetic plains extending up to the NE region while the Southern region experienced warming. For minimum temperature, all regions except the Central region reported increasing trends indicating warming. As a result, diurnal temperature range showed decreasing trends in many places in the upper half of the country while the lower half is dominated by increasing trends. On a regional scale, the Southern region, in particular, showed increasing trends in all three parameters. On seasonal scale, pre-monsoon and monsoon months remained mostly trendless for all three parameters. Maximum significant decreasing trends were observed during January-May while maximum increasing trends were reported during June-December. Also, a higher Sen slope value of the yearly maximum increase in the minimum temperature indicated steeper increase in minimum temperature over maximum temperature.