Radiative and boundary-layer controls of smog on surface heat flux variability - A review
DOI:
https://doi.org/10.53992/njns.v11i2.329Keywords:
Smog, Aerosols, Surface Energy Balance, Latent and Sensible Heat Fluxes, Boundary-Layer StabilityAbstract
Smog is one of the most persistent and widespread forms of air pollution in rapidly developing regions, especially over South and East Asia. While its impacts on human health and visibility have been documented quite well, its role regarding the modification of the land-atmosphere energy exchange has received relatively less attention. This review synthesizes current understanding of how smog-related aerosols modify surface heat flux variability by altering radiative transfer, boundary-layer structure, and near-surface thermodynamic conditions. Smog-associated aerosols cause surface dimming by reducing incoming shortwave radiation through scattering and absorption processes. The reduction in available energy suppresses surface heating and, consequently, the turbulent exchanges in the lower atmosphere. Under heavy aerosol loading, latent heat flux and sensible heat flux are found to be reduced in several observational and modeling studies from South Asia, East Asia, and many polluted regions. In addition, enhanced atmospheric stability and a shallower planetary boundary layer further reduce vertical mixing, reinforcing reductions in evaporation and heat transfer. Aerosol–humidity interactions might further introduce feedbacks related to cloud formation and moisture retention and are responsible for reduced diurnal and seasonal variability in surface fluxes. This paper highlights the key physical pathways through which smog influences surface energy balance by reviewing evidence from satellite observations, reanalysis products, and regional modeling studies. Understanding these mechanisms is of paramount importance in view of improving the representation of aerosol–boundary-layer interactions in regional climate models and assessing the longer-term climatic implications of sustained air pollution. The findings underline that smog is not merely a pollutant causing deterioration of air quality but also an active player in modulating the exchange of heat and moisture at the Earth's surface, impacting local temperature variability and hydrological processes
References
Li Z, Lau WKM, Ramanathan V, Wu G, Ding Y, Manoj MR, Liu J, Qian Y, Li J, Zhou T, Fan J, Rosenfeld D, Ming Y, Wang Y, Huang J, Wang B, Xu X, Lee SS, Cribb M, Zhang F. Aerosol and monsoon climate interactions over Asia. Rev Geophys. 2016; 54(4):866-929.
Saidou Chaibou AA, Ma X, Sha T. Dust radiative forcing and its impact on surface energy budget over West Africa. Sci Rep. 2020; 10:12881.
Tang T, Li C, Wang H, Liu X, Jiang F, Zhao C, Zhang Q, Zhu T. Distinct surface response to black carbon aerosols. Atmos Chem Phys. 2021; 21:13797-13810.
Zhou C, Wang L, Ma Y, Wang K, Liao H, Li Z. Effects of local aerosol and transported dust pollution on the surface energy balance over farmland in eastern China during spring. Front Environ Sci. 2022; 10:1059292.
Ramanathan V, Carmichael G. Global and regional climate changes due to black carbon. Nat Geosci. 2008; 1(4):221-227.
Petäjä T, Järvi L, Kerminen VM, Ding AJ, Sun JN, Nie W, Kujansuu J, Virkkula A, Yang X, Fu CB, Zilitinkevich S, Kulmala M. Enhanced air pollution via aerosol–boundary layer feedback in China. Sci Rep. 2016; 6:18998.
Wilcox EM, Lau KM, Kim KM. A northward shift of the South Asian monsoon rain belt due to absorbing aerosols. Geophys Res Lett. 2016; 43:9153-9161.
Dey S, Di Girolamo L. A climatology of aerosol optical and microphysical properties over the Indo-Gangetic Basin. J Geophys Res Atmos. 2011; 116:D15209.
Chen L, Chen H, Du X, Wang R. Retrieval of surface energy fluxes considering vegetation changes and aerosol effects. Remote Sens. 2024; 16(4):668.
Gautam R, Hsu NC, Lau KM. Premonsoon aerosol variability and its link to the monsoon onset. Geophys Res Lett. 2010; 37(5):L05806.
Su T, Li Z, Zheng Y, Wu T, Wu H, Guo J. Aerosol effects on the interannual variability of surface heat fluxes over East Asia. J Clim. 2020; 33:6205-6222.
Li Z, Guo J, Ding A, Liao H, Liu J, Sun Y, Wang T, Xue H, Zhang H, Zhu B. Aerosol and boundary-layer interactions and impact on air quality. Natl Sci Rev. 2017; 4(6):810-833.
Ling X, Liu X, Zhang C, Wang H. Aerosol impacts on meteorological elements and surface energy budget over the Yangtze River Delta. Aerosol Air Qual Res. 2019; 19(5):1009-1023.
Oh SS, Lee HJ, Kim MS, Park MS, Kim
CH. Aerosol–heat flux interactions in the boundary layer during the SIJAQ campaign. Atmos Environ. 2024; 319:120306.
Akhila R, Nair VS, Basheer AI, Suresh Babu S. Energy-balance decomposition of the aerosol-induced changes on surface temperature over South Asia. J Geophys Res Atmos. 2025; 130(14) :e2024JD043123.
Wilcox EM, Ramanathan V. The direct and semi-direct effects of absorbing aerosols on the climate system. J Clim. 2013; 26:8244-8263.
Oke TR. The energetic basis of the urban heat island. Q J R Meteorol Soc. 1982; 108(455):1-24.
Coumou D, Robinson A. Historic and future increase in the global land area affected by monthly heat extremes. Environ Res Lett. 2013; 8(3):034018.
Su T, Li Z, Zheng Y, Wu T, Guo J. Aerosol–boundary-layer interaction modulated entrainment process. NPJ Clim Atmos Sci. 2022; 5:64.
Zhang X, Dong X, Xi B, Zheng X. Aerosol properties and their influences on marine boundary layer cloud condensation nuclei over the Southern Ocean. Atmosphere. 2023; 14(8):1246.
