Resumen de Altering urban greenspace patterns and heat stress risk in Hanoi city during Master Plan 2030 implementation

Yuei-An Liou, Kim-Anh Nguyen, Le-Thu Ho

• Hanoi City has been greatly reshaped owing to its “Master Plan by 2030 and a vision to 2050 by Decision 1259/QD-TTg of Vietnam” (called Hanoi Master Plan thereafter). This Hanoi Master Plan results in multi-challenges for the Hanoi City in terms of conserving urban greenspace (UGS). This study pursues to (1) investigate the changing environmental spatial patterns of UGS, (2) identity the areas at high risk due to heat stress based on abnormal land surface temperature (LST) distribution and demographic vulnerability, and (3) suggest mitigation strategies to the authorities by using the proposed UGS management platform. Sentinel-2 multispectral instrument (MSI) data was used to examine the evolution of UGS in relation to LST derived from Landsat 8 OLI thermal band that was subsequently utilized to create heat stress risk patterns. The study region is the inner Hanoi City. The UGS was investigated during the timeframe from Oct. 2016 to Oct. 2018. Accuracy assessment was performed by using Google Earth and field survey data. Results showed that UGS in inner Hanoi City is much declined by 1.3% for woodland and by 4.4% for shrub land, while grass-cover is increased by 2.4% in recent 2 years. Overall accuracies are of 96% and 88% with Kappa coefficients of 0.92 and 0.78 for land cover classification in 2018 and 2016, respectively. Urban heat stress index patterns showed a higher risk in the central inner-city areas of dense residential regions characterized by dense built-up. The identification of environmental heat stress risk patterns provides useful information for calling more attention of urban planners, authorities and health organizations.