Land cover change and dry-season thermal patterns across the urbanizing areas in southeastern Vietnam
Abstract
Industrial urbanization is altering land cover and surface thermal conditions in southeastern Vietnam, but comparisons among secondary urban areas remain limited. This study compares impervious-surface expansion, vegetation indices, and February land surface temperature (LST) in selected urban areas of Binh Duong, Tay Ninh, and Binh Phuoc from 1999–2024. Eight Landsat scenes acquired in February between 1999 and 2024 were selected, comprising four Landsat 5 Thematic Mapper scenes and four Landsat 8 Operational Land Imager and Thermal Infrared Sensor scenes. Maximum likelihood classification was used to map land cover, while sensor-specific radiometric calibration and normalized difference vegetation index (NDVI)-based emissivity correction, using fixed NDVI endpoints of 0.2 and 0.5, were used to determine LST. Endpoint area statistics were subsequently calculated. Impervious area increased from 1,981 to 31,862 ha in Binh Duong, from 373 to 6,783 ha in Tay Ninh, and from 291 to 3,333 ha in Binh Phuoc. Endpoint-average net gains were 1,195, 256, and 122 ha per year. In 2024, mapped LST above 34 °C occupied 8,857, 81, and 348 ha in Binh Duong, Tay Ninh, and Binh Phuoc, respectively. Normalizing by the stated study extents yields high-temperature area shares of 8.91%, 0.32%, and 4.03%, distinguishing absolute high-temperature area from its relative coverage within each study mask. Land with NDVI > 0.4 covered 48,585, 18,802, and 6,593 ha, but these threshold areas are not equivalent to mutually exclusive vegetated land-cover classes. The results suggest contrasting corridor-led and clustered development patterns, and identify locations for further thermal assessment. Incomplete independent validation and unresolved atmospheric and emissivity uncertainties limit causal attribution and absolute-temperature interpretation. The comparison serves as a dry-season surface diagnostic rather than a continuous climatic trend or a measure of human heat exposure.