title: Urban heat islands in China enhanced by haze pollution.
abstract: The urban heat island (UHI), the phenomenon of higher temperatures in urban land than the surrounding rural land, is commonly attributed to changes in biophysical properties of the land surface associated with urbanization. Here we provide evidence for a long-held hypothesis that the biogeochemical effect of urban aerosol or haze pollution is also a contributor to the UHI. Our results are based on satellite observations and urban climate model calculations. We find that a significant factor controlling the nighttime surface UHI across China is the urban-rural difference in the haze pollution level. The average haze contribution to the nighttime surface UHI is 0.7±0.3 K (mean±1 s.e.) for semi-arid cities, which is stronger than that in the humid climate due to a stronger longwave radiative forcing of coarser aerosols. Mitigation of haze pollution therefore provides a co-benefit of reducing heat stress on urban residents.
authors.affiliation: Yale-NUIST Center on Atmospheric Environment and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.|School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, Connecticut 06511, USA.
authors.forename: Chang
authors.initials: C
authors.lastname: Cao
authors.affiliation: Yale-NUIST Center on Atmospheric Environment and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.|School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, Connecticut 06511, USA.
authors.forename: Xuhui
authors.initials: X
authors.lastname: Lee
authors.affiliation: Yale-NUIST Center on Atmospheric Environment and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
authors.forename: Shoudong
authors.initials: S
authors.lastname: Liu
authors.affiliation: School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, Connecticut 06511, USA.
authors.forename: Natalie
authors.initials: N
authors.lastname: Schultz
authors.affiliation: Yale-NUIST Center on Atmospheric Environment and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.|School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, Connecticut 06511, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Yale-NUIST Center on Atmospheric Environment and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
authors.forename: Mi
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Yale-NUIST Center on Atmospheric Environment and Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.|School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, Connecticut 06511, USA.|Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhao
mesh_terms: D000397:Air Pollution / Q000032:analysis*; D000465:Algorithms; D001272:Atmosphere / Q000032:analysis*; D002681:China; D002947:Cities; D002980:Climate; D004784:Environmental Monitoring / Q000379:methods; D005843:Geography; D006358:Hot Temperature; D014507:Urbanization