The impact of detailed urban-scale processing on the composition, distribution, and radiative forcing of anthropogenic aerosols

• Main Authors: Cohen, Jason Blake (Contributor), Prinn, Ronald G. (Contributor), Wang, Chien (Contributor)
• Other Authors: Massachusetts Institute of Technology. Center for Global Change Science (Contributor), Massachusetts Institute of Technology. Joint Program on the Science & Policy of Global Change (Contributor)
• Format: Article
• Language: English
• Published: American Geophysical Union (AGU), 2012-10-16T13:17:49Z.
• Subjects: Article
• Online Access: Get fulltext

 Detailed urban-scale processing has not been included in global 3D chemical transport models due to its large computational demands. Here we present a metamodel for including this processing, and compare it with the use of the traditional approach of dilution of emissions into large grid boxes. This metamodel is used in a global 3D model to simulate the effects of cities around the world on aerosol chemistry, physics, and radiative effects at the global scale. We show that the biases caused by ignoring urban processing on the global values of total aerosol surface concentration, the total aerosol column abundance, the aerosol optical depth (AOD), the absorbing aerosol optical depth (AAOD), and the top of the atmosphere radiative forcing (TOA) respectively are +26 ± +26 ± [subscript 3[superscript 2]]%, +51 ± +26 ± [subscript 10[superscript 12]]%, +42 ± [subscript 8[superscript 10]]%, +8 ± [subscript 16[superscript 18]]%, and −0.27 ± [subscript 0.14[superscript 0.10]] W/m2. These results show that failure to consider urban scale processing leads to significantly more negative aerosol radiative forcing compared to when detailed urban scale processing is considered.