Roles of past, present, and future land use and anthropogenic heat release changes on urban heat island effects in Hanoi, Vietnam: Numerical experiments with a regional climate model

This study investigates the roles of land-use cover (LUC) and anthropogenic heat (AH) on the past, present, and future urban heat island (UHI) effect over the megapolitan area of Hanoi, Vietnam. We use a dynamical downscaling method with a regional climate model coupled with an urban canopy scheme to run sensitivity simulations with LUC and AH data from 1990, 2010, and 2030. The LUC data in 1990 and 2010 are derived from remote sensing data, whereas the LUC data for 2030 come from the city's master plan. The AH data are estimated from past and projected energy-use conditions. The results show that the LUC-AH coupled changes during 2010-2030 will have much greater impact on the local UHI effect than those during 1990-2010. In the urban-core area, the monthly mean surface air temperature in July is predicted to increase by 0.7 degrees C by 2030, double the increase of 0.35 degrees C during 1990-2010. We show that the temperature increase during 1990-2010 is mostly due to the change in LUC conditions, but the increase in the future AH will contribute 30-50% to the total temperature increase in the urban areas.