Influence of geometrical shape on thermal heterogeneity in closed landfill sites

Thermal heterogeneity assessment in landfill sites is essential for identification of potential hazards. The relationship between landfill geometrical shape and land surface thermal heterogeneity is not well understood. This study examines the association between landfills' shape configuration and thermal heterogeneity by using two mathematical shape factors on thirty-eight closed landfills. Three different multiple linear regression models were developed for landfill sites of various sizes. Geometrical shape analysis of the sites shows that all landfills surpass the 0.5 threshold, suggesting a tendency toward regular shapes and a systematic approach in their design and operation, with a mean elongation and compactness shape factor of 0.819, and 0.724, respectively. This pattern likely accommodates land use constraints and proximity to neighboring properties, with boundaries confined by the surrounding road network. In larger landfill sites, the elongation shape factor exhibits a higher coefficient (−0.46) than the compactness shape factor (−0.35), indicating its stronger association on thermal heterogeneity of the site. This finding helps to develop strategies for better thermal management and environmental safety of large landfill sites. The negative coefficients for all the site groups (small, medium, and large) suggest that a more compact and regular shape may promote thermal homogeneity in closed landfills. The proposed method improves monitoring of closed landfills and contributes to the development of evidence-based landfill design guidelines and regulations. • Thermal heterogeneity of 38 closed landfills is assessed using satellite imagery. • Two shape factors are adopted to define geometrical shape mathematically. • Most closed landfills exhibit a higher degree of elongation than compactness. • Regular shaped landfills show lower thermal heterogeneity, regardless of size. • Smaller sites show the highest rectangularity due to neighboring sites.