Back to Search
Start Over
The mechanisms and seasonal differences of the impact of aerosols on daytime surface urban heat island effect
- Source :
- Atmospheric Chemistry and Physics, Vol 20, Pp 6479-6493 (2020)
- Publication Year :
- 2020
- Publisher :
- Copernicus GmbH, 2020.
-
Abstract
- The urban heat island intensity (UHII) is the temperature difference between urban areas and their rural surroundings. It is commonly attributed to changes in the underlying surface structure caused by urbanization. Air pollution caused by aerosol particles can affect the UHII through changing (1) the surface energy balance by the aerosol radiative effect (ARE) and (2) planetary-boundary-layer (PBL) stability and airflow intensity by modifying thermodynamic structure, which is referred to as the aerosol dynamic effect (ADE). By analyzing satellite data and ground-based observations collected from 2001 to 2010 at 35 cities in China and using the WRF-Chem model, we find that the impact of aerosols on UHII differs considerably: reducing the UHII in summer but increasing the UHII in winter. This seasonal contrast is proposed to be caused by the different strengths of the ARE and ADE between summer and winter. In summer, the ARE on UHII is dominant over the ADE, cooling down surface temperature more strongly in urban areas than in rural areas because of much higher aerosol loading, and offsets the urban heating, therefore weakening UHII. In winter, however, the ADE is more dominant, because aerosols stabilize the PBL more in the polluted condition, weakening the near-surface heat transport over urban areas in both vertical and horizontal directions. This means that the heat accumulated in urban areas is dispersed less effectively, and thus the UHII is enhanced. These findings shed new light on the impact of the interaction between urbanization-induced surface changes and air pollution on urban climate.
- Subjects :
- Atmospheric Science
Daytime
010504 meteorology & atmospheric sciences
Airflow
Air pollution
010501 environmental sciences
Atmospheric sciences
medicine.disease_cause
01 natural sciences
lcsh:QC1-999
Aerosol
lcsh:Chemistry
lcsh:QD1-999
Urbanization
Urban climate
medicine
Environmental science
Urban heat island
lcsh:Physics
Intensity (heat transfer)
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 16807324
- Volume :
- 20
- Database :
- OpenAIRE
- Journal :
- Atmospheric Chemistry and Physics
- Accession number :
- edsair.doi.dedup.....530cce01fca2880b7d677373d281a466