Year: 2025
Type: article
Abstract: Globally, increasing air moisture limits not only the human body’s ability to cool down, but also the Earth’s surface. A gap remains, however, in understanding how limited surface cooling can quantitatively impact metrics of thermal comfort. Here, we examine how air moisture influences nighttime land surface temperatures (LSTs) and thermal comfort during summer months across the Florida peninsula, during which time air moisture reaches the highest values of any place in the United States. For June–August during 2018–2022, we ask: 1) How do urbanicity, measured as impervious surface, and geography, measured as latitude and distance from the coast, modulate air moisture, measured as specific humidity? 2) How does specific humidity limit LST cooling at night? And 3) what are the resulting consequences for thermal comfort? Based on data from 30 weather stations along the peninsula, we find that specific humidity increases closer to the coast and at lower latitudes. In regions with higher air moisture levels, LSTs cool off less at night (as measured at 1 AM), resulting in lower differences between daytime and nighttime (diurnal) LSTs. Elevated nighttime LSTs have pronounced implications for measures of thermal comfort—for every 1.0 °C increase in nighttime LST, nighttime surface air temperatures increase, on average, by 1.1 °C, heat indices by 2.0 °C, and wet bulb temperatures by 0.5 °C. This analysis therefore underscores the importance of heat mitigation and adaptation strategies that reduce elevated nighttime LSTs in seasonally muggy climates, increasing thermal comfort.
Source: Climatic Change
Institutions: Harvard University, University of Miami
Language: English
Topic: Urban Heat Island Mitigation
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,390
OpenAlex ID: W4414948178