Hot Topic: Using Satellite and Ground-Based Measurements to Estimate Air Temperature and Identify Vulnerable Communities in Baltimore City

Health impacts caused by extreme heat events are well documented and can be exacerbated by Urban Heat Islands (UHIs). The UHI effect is the phenomenon where urbanized areas experience higher surface and air temperatures compared to surrounding regions. The UHI is not uniform within a city, and the concept of the urban heat archipelagoi.e., fine spatial variability in the UHIis now generally appreciated. Variability in archipelago patterns with time and meteorological conditions, however, is relatively less studied. Here, we estimate the variability in temperature within Baltimore City and observe spatial and temporal patterns in this variance. We aim to predict temperature differences between local temperature measurements and the nearest National Weather Service (NWS) station measurements at daily temporal resolution. A ground-based sensor network of iButton thermometers was used to measure and monitor intra-urban air temperatures. These measurements are used to train a statistical model that uses measurements from satellites and NWS stations to predict spatial and temporal variability in air temperature throughout Baltimore City. These time-varying temperature maps are then combined with socio-economic and demographic data to determine which regions are most vulnerable to extreme heat events at the census tract level. This information can be used by local government officials and emergency planners to devise and implement heat mitigation efforts. The approaches developed in this study can be applied to other cities and used as a tool to identify communities and neighborhoods most vulnerable to extreme heat.