Impacts of Aerosol Dry Deposition on Black Carbon Spatial Distributions and Radiative Effects in the Community Atmosphere Model CAM5

• Published in: Journal of Advances in Modeling Earth Systems
• Main Authors: Wu, Mingxuan, Liu, Xiaohong, Zhang, Leiming, Wu, Chenglai, Lu, Zheng, Ma, Po-Lun, Wang, Hailong, Tilmes, Simone, Mahowald, Natalie, Matsui, Hitoshi, Easter, Richard C.
• Language: unknown
• Published: 2022
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic; Aitken; black carbon
• Online Access: http://www.osti.gov/servlets/purl/1558382; https://www.osti.gov/biblio/1558382; https://doi.org/10.1029/2017MS001219

Dry deposition is a vital process affecting the lifetime and spatial distributions of atmospheric aerosols. Black carbon (BC) plays an important role in the Earth’s climate. To explore the sensitivity of modeled BC spatial distributions to particle dry deposition treatments, the scheme of Petroff & Zhang (2010) (PZ10) is implemented into the Community Atmospheric Model version 5 (CAM5), and model simulations using PZ10 are compared with the one using the default scheme of Zhang et al. (2001) (Z01). The PZ10 scheme suggests much lower dry deposition velocities than Z01 for fine particles in Aitken, primary carbon, and accumulation modes, resulting in 73.0% lower of global mean BC dry deposition fluxes and 23.2% higher of global mean BC column burdens. CAM5 with PZ10 increases modeled BC concentrations at all altitudes and latitudes compared to Z01, which improves the agreement with observations of BC profiles in the lower troposphere in the Arctic. It also helps the simulation of surface BC concentrations in high-latitudes remote regions and its seasonality in the Arctic. Yet, PZ10 slightly exacerbates the overestimation of modeled BC concentrations in the middle and upper troposphere, which might be due to model uncertainties in other aerosol physical and chemical processes. The global annual mean radiative effects due to aerosol-radiation interactions (REari) and aerosol-cloud interactions (REaci) of BC from the CAM5 experiment using Z01 are 0.61±0.007 and -0.11±0.02 W m -2 , respectively, compared to slightly larger REari (0.75±0.01 W m -2 ) and REaci (-0.14±0.02 W m -2 ) from CAM5 using PZ10.