Using subsurface temperatures to derive the spatial extent of the land use change effect

Luminda Niroshana Gunawardhana, So Kazama

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The urban heat island (UHI) effect has traditionally been determined using ambient air temperatures or land surface temperatures derived from satellite observations. In this study, we used the subsurface temperature anomaly as an indicator in describing a relationship between land use characteristics and aquifer temperature changes in the shallow subsurface layers of three rapidly developing urban settings: the Kanto, Sendai and Chikushi plains in Japan. Information on land cover was derived from Landsat Enhanced Thematic Mapper Plus (ETM+) images acquired between 1999 and 2001. The supervised classification technique along with the Normalized Difference Vegetation Index (NDVI) was used to specify the urban degree for grid cells covering observation wells. Preliminary analysis of groundwater levels in different well locations revealed that vertical groundwater recharge is predominant in all study areas. A numerical model for subsurface heat transport employed with different groundwater recharge/discharge and ground surface warming rates indicated that ground surface warming has a significant effect on aquifer temperatures in shallow subsurface layers. The results show that the magnitude of aquifer temperature change is positively correlated with the degree of impervious area derived from the NDVI values (i.e., negatively correlated with the NDVI value with 0.5-0.7°C warming for a 0.12NDVI difference at a 20-m depth). The relationship between aquifer temperature changes and grid-averaged NDVI values was strongest at an area of approximately 99,225m 2 (roughly equal to an area with a 175-m radius) and determination coefficient equal to 0.91 for the Kanto plain. As the average area is further increased, the relationship between the two variables gradually became weaker. According to results verified for the Sendai and Chikushi plains, the same relationship was achieved for areas no larger than 175 (±15)m radius and a determination coefficient of 0.81, which is suggested as the operational spatial scale to determine the UHI effect on subsurface thermal regimes. As the necessity for adaptation measures to cope with urban thermal pollution is increasingly understood, the lateral extent of subsurface heat flow found in this study may be useful in urban planning and habitat restoration programs.

Original languageEnglish
Pages (from-to)40-51
Number of pages12
JournalJournal of Hydrology
Publication statusPublished - 2012 Aug 16


  • Aquifer temperature
  • Japan
  • NDVI
  • Spatial extent
  • Urban heat island


Dive into the research topics of 'Using subsurface temperatures to derive the spatial extent of the land use change effect'. Together they form a unique fingerprint.

Cite this