STUDY OF THE RELATIONSHIP BETWEEN SURFACE TEMPERATURE AND GREEN AREA : A CASE STUDY OF THOEN DISTRICT, LAMPANG PROVINCE

Abstract

This research investigates the relationship between green area and Land Surface Temperature (LST) in Thoen District of Lampang Province, which is the center of Northern Thailand. The Thoen District is a semi-urban area with rapid development of road transport infrastructure. The primary goal of the research is to investigate the relationship between vegetation cover and LST using changes in land use and land cover (LULC) based on Landsat-8 satellite images from 2018 (April 9, 2018) and 2023 (April 24, 2023) The research method combines remote sensing with a stepwise statistical method. Findings indicate a statistically significant inverse relationship between the Normalized Difference Vegetation Index (NDVI) and LST for both study periods. The relationship is as expected from urban ecology, where densely covered areas with plants are capable of decreasing the surface temperature effectively by capturing solar radiation and delivering moisture back into the atmosphere via evapotranspiration. Yet, when comparing 2018 and 2023 time series, average LST is seen to be on a rising trend, with NDVI decreasing in some parts of the area, especially from urban areas and cultivation fields. These indicate the beginning of locally scaled climate warming and climate change impacts across the region. The topography of Thoen, with forested foothills, indicates that the decrease in green cover may compromise thermal balance and is likely to have a bearing on the area’s biodiversity, as well as on the sequestration capacity of the ecosystem, factors for long-term climate adjustment. Applying NDVI and LST as indicators of landscape condition at a local scale improves monitoring of environmental changes and provides scientific evidence for sustainable land management, urban design, and preventive measures to reduce localized climate effects.