Exploring the evolution of urban heat island and assessing risk of heat wave based on big data

Rapid urbanization has changed the land use and land cover significantly in recent years which influenced the energy balance, carbon budget, and hydrological cycle on earth's surface. Consequently, urban heat island was considered an obvious and big side-effect on people who live in a local city under urbanization process. However, the evolution rates, and spatiotemporal distribution and the possibility transformed to heat waves of UHIs remain unclear which causing human unknow what the damage on people and how to regulate the urban landscape. In this study, we integrate meteorological observation data, remote sensed data, demographic data and point of interest (POI) data; analyze the influence of urbanization on the urban thermal environment; explore the possibility of a sudden heat wave, and the relationship between the urban vulnerability environment and heat-wave-related mortality. Finally, we map the distribution of high temperature regions, high heat-wave-related mortality risk based on the results of heat wave hazard and social human distribution. The results reveal that (1) the urban center is usually a high-temperature area which is constantly expanding with urban expansion while people gathering, leading more people exposed to the high thermal area; (2) with the continuous population gathering and the aggravation of climate changing, the frequency of urban heat waves would be higher; (3) heat waves are more of a large-scale meteorological event, and the suburban areas are also vulnerable to it. Finally, this study explores the factors contributing to heat waves and the spatial distribution of the disaster mortality, and the possible methods to reduce the impact from heat waves are proposed.