Retrieval of temperature from satellite remote sensing and its effect on rice and wheat productivity in different agro-climatic regions of Punjab
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Date
2018
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Punjab Agricultural University, Ludhiana
Abstract
Land surface temperature 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 affect on crop yield (rice
and wheat) in SBS Nagar, Ludhiana and Bathinda districts representing different agroclimatic
zones of Punjab (India). The urban heat island (UHI) intensities were also modelled
in one major city (Balachaur in SBS Nagar district, Ludhiana city in Ludhiana district and
Bathinda city in district) of each district. The Landsat satellite imageries were classified for
the major LULC classes (vegetation (including agriculture and forest), water, built-up and
bare soil) in each district using different spectral indices. Normalised Difference Vegetation
Index (NDVI) was used for extracting vegetation, Modified Normalised Difference Water
Index (MNDWI) for extracting water, Normalized Difference Built-Up Index (NDBI) for
extracting built-up and Normalized Difference Bareness Index (NDBaI) for extracting bare
soil. 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 land surface temperature has increased in these districts over
the years, but the rate of increase was highest in Ludhiana district. The relationships between
air temperature and LST showed that air temperature can be predicted from LST using
equation Ta = 0.86 Ts (where Ta is air temperature and Ts is land surface temperature). NDVI
was significantly positively correlated with rice and wheat yield, but significantly negatively
correlated with LST. Compared with 1991, there was an increase in temperature of built-up
over the years in all the cities, but the degree of increase was highest from 1991 to 2001. The
temperature of urban areas around vegetation and water bodies was lower than the urban
areas devoid of these features. The UHI effect was mainly in the range between 2 and 4oC for
Balachaur city, between 4 and 6oC for Bathinda city and between 2 and 6oC for Ludhiana city.
The area under worst thermal condition (UTFVI > 0.020) was highest in Bathinda city (46.1%
area) followed by Ludhiana and Balachaur cities (31.6% each).
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