LULC Impacts on NDVI and LST: A Case Study on Jashore District, Bangladesh

Abstract

Studies on land use and land cover (LULC) changes and subsequent effects on environment are not satisfactory in Bangladesh because of the lack of geospatial data and time-series information. By using the open-source Landsat 7 and Landsat 8 imagery data coupled with GIS technology and other ancillary data, the main purpose of this study is to analyze the dynamic changes in LULC in Jashore district of Bangladesh over a 20-year period between 2002 and 2022. Including pre-classification and post-classification identification scenarios, Normalized Difference Vegetation Index (NDVI) analysis was employed to examine the vegetation changes over the period. ArcGIS 10.8 software was employed for analyzing satellite images, and maximum likelihood classification was utilized to create supervised land cover category (water bodies, vegetation, built-up area, and bare soil). Microsoft Excel was used for data analysis and visualization. The findings of this present study indicate notable changes with an increase of 20.77% in urban areas and 14.53% in bare soil. Additionally, there has been a decline of 2.93% in water bodies and 32.37% in vegetation land cover including both natural and anthropogenically modified vegetation such as forests, croplands, grasslands and others. Accuracy evaluations on the land use classification's trustworthiness include Kappa statistics of 0.80 for the year 2022 and 0.65 for the year 2002. A decrease in land surface temperature (LST) in Jashore district over 20 years from 2002 to 2022 has been reported in this study. Although the proportion of vegetation cover has been reduced in 2022, we found a negative correlation between LST and NDVI. Along with LULC, the LST is influenced by many atmospheric and ecological parameters. NDVI is dependent on vegetation canopy type, color and density, which could affect the relationship with LST. The findings of this study provide insightful information to ecologists, environmentalists, urban planners, and lawmakers for developing sustainable land management plans and environmental conservation initiatives.