Field Notes
Do urban heat islands exist in an Arctic city?
By Howard Epstein and Jana Peirce | October 2026
Principal Investigator Dr. Howard Epstein shares insights on how buildings affect ground temperature and permafrost thaw at sites across Utqiaġvik in a meeting at
Ilisaġvik College on May 27, 2026. (Courtesy: Ilisaġvik College)
An urban heat island (UHI) is a metropolitan area that is significantly warmer than surrounding rural areas due to human modification of the land. Prior studies in
Utqiaġvik conducted in 2001-2002 and 2004-2006
found a minimally significant heat island effects in summer and and a more prominent effect (~2 °C) in winter.
To understand the dynamics of urban heating at fine spatio-temporal scales, we established an network of micrometeorological sensor arrays
to continuously measure ground temperature, ground moisture, air temperature, wind speed/direction, and solar radiation at three locations around town (hospital, utilities, residential) and one tundra site
(Barrow Environmental Observatory)
outside of town. Looking at three years of data (2022-2025), our results show a very strong urban heat island effect around
infrastructure down to approximately 50-55 cm depth that varies by aspect (location
around the building) and how the building was constructed. Averaged across all sites, summer air temperatures were 3.8 °C greater in the urban settings compared to the tundra site, while near-surface ground temperatures (at 10cm depth) were an average of 2.5 °C greater in the urban settings.
Interestingly, at most urban locations,
temperatures at greater depths (e.g., below 55 cm) were substantially colder than
corresponding depths at the tundra site. This coud bedue to raised buildings shading the ground beneath or to differences in ground composition.
No clear story has emerged for other times of year. Air temperatures at some urban locations were consistently colder than the tundra site, while temperatures at other buildings were similar to the tundra. Ground temperatures at the surface and at depth also varied by site, with some urban sites warmer and some cooler than the tundra. Active layer depths (the depth to frozen ground) were highly variable across our measurement locations. This work was conducted by Ph.D. candidate, Mirella Shaban, who will be defending her dissertation on November 20. In September, we installed ten new sets of ground
temperature and moisture monitoring equipment at five locations
across town, with the goal of understanding the impact of ground moisture on permafrost stabilty. At each of the sties, one set of sensors is installed in an area that remains
relatively dry and one in a nearby area that accumulates surface water.