Heat stress is a leading cause of weather-related deaths and can be especially dangerous in cities where phenomena like urban heat islands drive temperatures higher than surrounding rural areas. Now a new dataset developed by the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR) aims to provide city governments and health officials with information that could minimize heat impacts on residents.
The layout of a city including the height and density of buildings can affect not just the number on the thermometer, but whether it feels cooler or hotter due to factors like wind and shade. This means more information than just temperature is needed to understand the true impacts of extreme heat on residents.
Researchers at NSF NCAR, Emory University, and University of North Carolina at Chapel Hill believed high-resolution urban meteorology datasets could help and began by focusing on Atlanta. The result is the High-resolution Urban Meteorology for Impacts Dataset for Atlanta Metropolitan Region (HUMID-Atlanta).
"This is a useful tool in actually quantifying how human beings experience heat in an urban environment and how factors like wind or humidity influence the impacts," said Tzu-Shun Lin, an NSF NCAR scientist and lead author of the paper. "HUMID-Atlanta is just the first dataset of its kind. We're already talking with other major cities and looking into the possibility of creating a version for the entire conterminous U.S."
This research was funded by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases and is published in the journal Scientific Data.
Adding in the atmosphere
To create HUMID-Atlanta, Lin and his colleagues started with an existing dataset called HUMID that was also developed at NSF NCAR. The HUMID dataset was created using an offline simplistic urban model combined with measurements of temperature and humidity for the years 1980-2018. While it was an important research advancement, it did not capture how the atmosphere interacts with the urban environment.
To improve HUMID, the research team coupled it with NSF NCAR's Weather Research and Forecasting model (WRF) , piloting the method on the Atlanta metropolitan area. WRF has the ability to incorporate more details about an urban environment through the WRF-Urban extension. Adding characteristics like building height makes it so HUMID-Atlanta can capture details such as how wind moves around buildings and influences cooling, a factor that can change how humans are affected by heat.
The resulting enhanced dataset analyzed the years 2010-2023 and can be used to cross-reference records, such as hospitalizations, with detailed heat data from the same time period. This can help researchers identify what mix of weather and infrastructure leads to spikes in heat stress. In turn, identifying when and where dangerous conditions are likely to occur can help with planning and interventions that could reduce residents' exposure to extreme heat.
HUMID-Atlanta is publicly available. Lin and other NSF NCAR researchers are continuing to improve the method and have already extended the HUMID-Atlanta dataset through the year 2025. There are plans to use the method for other large cities, the entire U.S., and possibly even globally. Lin believes this method could also be further developed to forecast future meteorological changes and serve as a potential tool for early warning systems for extreme heat action days.
Focusing on health
HUMID-Atlanta is already being used to understand and assess heat-health impacts in urban environments. Andrew Newman, an NSF NCAR senior scientist and co-author of the paper, is working with colleagues at Emory University to help them use the dataset to better understand the impacts of heat waves on human diseases such as acute kidney injury (AKI), which causes a rapid decline in kidney function.
Previous work that analyzed links between kidney diseases and heat exposure failed to capture differences in how people experience heat depending on whether they live in city centers, surrounding suburbs, or rural areas. HUMID-Atlanta is helping to narrow in on where the risks are highest and what can be done to mitigate harm to people.
"Not only is acute kidney injury a serious health concern, but the economic burden of treating those with it is substantial,"said Newman. "HUMID-Atlanta and subsequent versions have the ability to fill major gaps in heat health research. This research will ultimately support targeted outreach and education activities, guide improvements in clinical case management, and provide inputs for risk assessment and economic evaluation of heat-health impacts."
