Configuration of green spaces for urban heat island mitigation and future building energy conservation in Hanoi Master Plan 2030

Abstract

The study aims to assess the urban heat island (UHI) effects in the city under the present land use conditions as well as those conditions proposed by the Hanoi Master Plan 2030 through numerical simulation, using Weather Research and Forecasting (WRF). Furthermore, this paper assesses additional land use scenarios with different spatial and green space configurations. The results show that the implementation of the master plan does not significantly affect the peak air temperature in the built-up areas (approximately 1 °C higher at the maximum). However, high temperature areas, with temperature of 40-41 °C, would expand widely over the new built-up areas. On the other hand, the nocturnal air temperature would increase by up to 2-3 °C over the newly expanded built-up areas. The number of hotspots increased further when the strategic green spaces in the master plan were not taken into account. However, the cooling effect of the strategic green spaces did not reach the existing city center sufficiently because the green spaces are located far from the city center. The large and centralized green spaces proposed in the master plan were seen to be insufficient to mitigate UHIs compared to the equally distributed green spaces. Moreover, the greater reduction of hotspot areas by up to 56.5% was seen when the mixed forest is employed as the land cover in the green spaces.