Engaging Citizen Scientists in Urban Heat Island Investigations

Urban areas tend to be significantly warmer than their adjoining suburban regions, a phenomenon known as the Urban Heat Island Effect (UHIE). Although the UHIE has been documented thoroughly on citywide scales, there is much still to be learned about temperature variations within and across neighborhoods at the local level. Satellite imagery often lacks the high degree of spatial and temporal resolution necessary to capture variation in complex urban environments, necessitating the integration of ground-based data. Citizen scientists have the potential to fill in the gaps in satellite data by participating in investigations of the UHIE in their local communities. Temperatures from the heterogeneous, urban land surface and the overlying air are relatively easy to collect, and often reveal consequential contrasts at the hyperlocal scale. Ground-based data are being collected in Brooklyn, NY using a variety of strategies. In one example, as part of a UHIE investigation that is funded by NOAA, citizen scientists are capturing detailed temperature variations by driving pre-planned routes three times over the course of a single day with a temperature sensor attached to their vehicles. As part of another effort, citizen scientists of all ages conduct one block walks to collect surface temperature data from a variety of land surfaces. These walks are intentionally timed to align with satellite flyovers. The resulting datasets play a major role in calibration/validation studies for satellite derived land surface temperatures in urban areas. Key considerations in the development of UHIE investigations include: designing easily-replicable protocols that minimize the potential for errors; identifying tools and technology that are affordable and accessible, yet also provide an acceptable level of precision; determining effective strategies for data sharing, and scaffolding the citizen science experience so that the data collected has meaning and relevance to program participants. Preliminary results indicate that ground-based data can be integrated into satellite data to add enhanced nuance and detail in targeted interest areas, but trade-offs include time and resource costs of recruiting, training, and supporting citizen scientists.