Influence Of The Changes In Land-Use And Land Cover On Temperature Over Northern And North-Eastern India

This study explores the influence of land-use and land cover (LULC) changes on the temperature over North India (NI) and North-Eastern India (NEI) during 1981-2006 by subtracting the reanalysis temperature from the observed temperature (observation minus reanalysis (OMR) method). The normalized difference vegetation index (NDVI) data of the AVHRR satellite for the period 1981-2006 were analyzed to understand the type of LULC changes during this period and their linkage with the temperature change over the two regions. The results from OMR indicated that the LULC change over NI during 1981-2006 resulted a warming of 0.03 degrees C, and that of NEI during this period resulted a cooling of 1.5 degrees C. The results from LULC changes during the said period indicated an increase of dry land/snow cover and agriculture/fallow land by similar to 0.1% of total area and a decrease of shrubs/small vegetation and dense forest over NI by about 0.1-0.2%. Over NEI, the areas under agricultural/fallow land, open forest and dense forest showed an increase by about 0.8-2.4% during this period, and the areas under dry/snow cover and shrubs/small vegetation indicated a decrease by similar to 0.7-3.6%. The comparison between the OMR analysis and LULC changes indicated that the warming over NI during 1981-2006 is due to the expansion of the dry land and the decline of dense forest. On the other hand, the cooling over NEI during the period is attributed to the decline of non-vegetated/small vegetated lands and the expansion of agricultural land/forest covers in that period. This study has an overall implication towards the modeling studies for the impact assessment of LULC changes in the present as well as future climate.