Satellite-based assessment of rapid mega-urban development on agricultural land

Observations of urbanization will provide a framework for understanding the biophysical processes caused by artificial land changes. Sejong Multifunctional Administrative City (MAC) is under development since 2006 to decentralize the function of Seoul, the capital city of South Korea. MAC was originally agricultural land and now is rapidly developing to mega-city. Using U. S. Air Force Defense Meteorological Satellite Program’s Operational Linescan System (DMSP-OLS) and Moderate-resolution Imaging Spectroradiometer (MODIS) satellite data, the spatio-temporal characteristics of nighttime light (NTL) emission, normalized difference vegetation index (NDVI), land surface temperature (LST), and surface albedo were investigated in MAC and its adjacent cities. NTL was generally stronger in the presence of vegetation degradation and surface warming conditions. LST was negatively correlated with a growth in vegetation. Those relationships among NTL, LST, and NDVIwere shown both in temporal change at MAC and spatial variation of MAC’s adjacent cites. Further, because the ratio value of LST to NDVIwas similar in temporal and spatial scales, these two indices can be used as important indicator of urbanization. However, surface albedo is not suitable to represent the temporal transition from rural to urban state because tall buildings can often bring relatively low surface albedo by blocking outgoing radiation.