Abstract
Land surface temperature (LST) is an important indicator of the earth’s environmental analysis which is significantly affected by changes in land use/land cover (LULC). The Landsat 5, 7 and 8 satellite data of January and September of the years 1991, 2001, 2011 and 2016 was used to study the impact of LULC changes on LST and its effect on crop yield (rice and wheat) in SBS Nagar, Ludhiana and Bathinda districts representing three different agro-climatic zones of Punjab (India). The Landsat satellite imageries were classified for the major LULC classes (water, vegetation [including agriculture and forest], built-up and bare soil) in each district using different spectral indices. The results showed that vegetation is the key land provider for built-up development in SBS Nagar and Ludhiana districts, whereas bare soil and water bodies were the main contributor of land for expansion of built-up and vegetation over the years in Bathinda district. Compared with 1991, the surface temperature of all the land cover features has increased over the years and the increase in temperature was higher for built-up features. Among different districts, the rate of increase was highest in Ludhiana district due to higher urban sprawl. The increase in temperature was higher in the direction where land use has been changed from agriculture, bare soil and forest to urban. The air temperature in agro-climatic regions of Punjab can be estimated from LST by multiplying it with a factor of 0.86. Normalized difference vegetation index (NDVI) was significantly positively correlated with rice and wheat yield, but significantly negatively correlated with LST. It is concluded that there is potential link between LULC and crop yield via impacts on horizontal surface temperature gradients which can be differentiated from Landsat data.
Disclosure statement
No potential conflict of interest was reported by the authors.