BioCAS: Biometeorological Climate impact Assessment System for Building-scale Impact Assessment of Heat-stress Related Mortality

An urban climate analysis system for Seoul was combined with biometeorological models for spatially distributed assessment of heat stress risks in urban areas. The Biometeorological Climate impact Assessment System (BioCAS) is based on the Climate Analysis Seoul (CAS) workbench, which provides urban planners with gridded data relevant for local climate assessment at 25 m and 5 m spatial resolutions. The influence of building morphology and vegetation on mean radiant temperature Tmrt was simulated by the SOLWEIG model. Gridded hourly perceived temperature PT was estimated using the Klima-Michel Model for a heat event day in 2012 using data from the CAS workbench and gridded T_mrt, along with relative humidity and wind speed observed at the Seoul Weather Station. Daily maximum perceived temperature PT_max was mapped and applied to an empirical-statistical model that explains the relationship between PT_max and excess mortality rate r_EM in Seoul, expressed as mortality increase relative to the expected base mortality. The resultant r_EM map quantifies the detrimental impact of the heat wave event at the building scale. Maximum values of r_EM in old and new town areas in an urban re-development site in Seoul were estimated at 51% and 8%, respectively, indicating that urban re-development in this area has generally resulted in a significant reduction of heat-stress related mortality. The study illustrates that BioCAS can be generally applied for quantification of the impacts of severe weather heat events on human health for different urban development scenarios with variable building morphologies and vegetation. Further improvements are required, particularly to consider indoor climate conditions causing heat stress, as well as socio-economic status and population structure of local residents.