Modeling of the anthropogenic heat flux and its effect on regional meteorology and air quality over the Yangtze River Delta region, China

Abstract

Abstract. Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and diurnal variations into the simulations. By running this upgraded WRF/Chem for 2 typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over the YRD have been growing in recent decades. In 2010, the annual-mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m −2 , respectively, with the high value of 113.5 W m −2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 • C in January and 1.4 • C in July, the PBLH (planetary boundary layer height) rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s −1 in January and 0.5 m s −1 in July, with a higher increment at night. The enhanced vertical movement can transport more moisture to higher levels, which causes the decrease in water vapor at ground level and the increase in the upper PBL (planetary boundary layer), and thereby induces the accumulative precipitation to increase by 15-30 % over the megacities in July. The adding of AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near the surface and increase at the upper levels, due mainly to the increases in PBLH, surface wind speed and upward air vertical movement. But surface O 3 concentrations increase in the urban areas, with maximum changes of 2.5 ppb in January and 4 ppb in July. Chemical direct (the rising up of air temperature directly accelerates surface O 3 formation) and indirect (the decrease in NO x at the ground results in the increase in surface O 3 ) effects can play a significant role in O 3 changes over this region. The meteorology and air pollution predictions in and around large urban areas are highly sensitive to the anthropogenic heat inputs, suggesting that AH should be considered in the climate and air quality assessments.

Changes in regional meteorology induced by anthropogenic heat and their impacts on air quality in South China

“…It was reported that the typical values of AH fluxes in urban areas range from 20 to 100 W m −2 (Crutzen, 2004;Sailor and Lu, 2004;Fan and Sailor, 2005;Pigeon et al, 2007;Lee et al, 2009;Iamarino et al, 2012;Lu et al, 2016;Xie et al, 2016). Sometimes, the fluxes might exceed the value of 100 W m −2 (Iamarino et al, 2012;Quah and Roth, 2012;Lu et al, 2016;Xie et al, 2016), with the extreme value of 1590 W m −2 in the densest part of Tokyo at the peak of air-conditioning demand (Ichinose et al, 1999).…”

“…surfaces to artificial ones (Civerolo et al, 2007;Lo et al, 2007;Wang et al, 2007;Jiang et al, 2008;Lu et al, 2010;Wu et al, 2011;Chen et al, 2014b;Liao et al, 2015;Zhu et al, 2015;Li et al, 2016) and the release of anthropogenic heat from human activities in cities (Ryu et al, 2013;Yu et al, 2014;Xie et al, 2016). Anthropogenic heat (AH) can increase turbulent fluxes in sensible and latent heat (Oke, 1988), implying that it can modulate local and regional meteorological processes (Ichinose et al, 1999;Block et al, 2004;Fan and Sailor, 2005;Ferguson and Woodbury, 2007;Zhu et al, 2010;Feng et al, 2012Feng et al, , 2014Menberg et al, 2013;Ryu et al, 2013;Wu and Yang, 2013;Bohnenstengel et al, 2014;Chen et al, 2014a;Meng et al, 2011;Yu et al, 2014;Xie et al, 2016) and thereby exert an important influence on the formation and the distribution of ozone (Ryu et al, 2013;Yu et al, 2014;Xie et al, 2016) as well as aerosols (Yu et al, 2014;Xie et al, 2016).…”

“…Anthropogenic heat (AH) can increase turbulent fluxes in sensible and latent heat (Oke, 1988), implying that it can modulate local and regional meteorological processes (Ichinose et al, 1999;Block et al, 2004;Fan and Sailor, 2005;Ferguson and Woodbury, 2007;Zhu et al, 2010;Feng et al, 2012Feng et al, , 2014Menberg et al, 2013;Ryu et al, 2013;Wu and Yang, 2013;Bohnenstengel et al, 2014;Chen et al, 2014a;Meng et al, 2011;Yu et al, 2014;Xie et al, 2016) and thereby exert an important influence on the formation and the distribution of ozone (Ryu et al, 2013;Yu et al, 2014;Xie et al, 2016) as well as aerosols (Yu et al, 2014;Xie et al, 2016).…”

“…It was reported that the typical values of AH fluxes in urban areas range from 20 to 100 W m −2 (Crutzen, 2004;Sailor and Lu, 2004;Fan and Sailor, 2005;Pigeon et al, 2007;Lee et al, 2009;Iamarino et al, 2012;Lu et al, 2016;Xie et al, 2016). Sometimes, the fluxes might exceed the value of 100 W m −2 (Iamarino et al, 2012;Quah and Roth, 2012;Lu et al, 2016;Xie et al, 2016), with the extreme value of 1590 W m −2 in the densest part of Tokyo at the peak of air-conditioning demand (Ichinose et al, 1999). With regard to their effects, the researchers found that AH fluxes can cause urban air temperatures to increase by several degrees (Fan and Sailor, 2005;Ferguson and Woodbury, 2007;Zhu et al, 2010;Feng et al, 2012Feng et al, , 2014Menberg et al, 2013;Wu and Yang, 2013;Bohnenstengel et al, 2014;Chen et al, , 2014aYu et al, 2014;Xie et al, 2016), induce the atmosphere to be more turbulent and unstable, change the urban heat island circulation, strengthen vertical air movement (Ichinose et al, 1999;Block et al, 2004;Fan and Sailor, 2005;Feng et al, 2012Feng et al, , 2014Bohnenstengel et al, 2014;Yu et al, 2014;Xie et al, 2016), enhance the convergence of water vapor in cities, and change the regional precipitation patterns (Feng et al, 2012(Feng et al, , 2014Xie et al, 2016).…”

Impact of Highly Reflective Materials on Meteorology, PM10 and Ozone in Urban Areas: A Modeling Study with WRF-CHIMERE at High Resolution over Milan (Italy)

“…The redistribution of primary and secondary pollutants between the surface and the upper levels of the atmosphere also plays a crucial role. According to [11], this phenomenon, together with the increase in temperature, results in an increase in surface ozone concentrations in urban areas with a maximum of 2.5 ppb in winter and 4 ppb in summer. The authors of [12] show that on average, daytime ozone concentrations decrease by about 2 ppbv in the lower boundary layer, while they increase by about 40 ppbv in the upper levels in a city downwind of Shanghai.…”