Global source attribution of sulfate concentration and direct and indirect radiative forcing

Abstract

Abstract. The global source-receptor relationships of sulfate concentrations, and direct and indirect radiative forcing (DRF and IRF) from 16 regions/sectors for years 2010-2014 are examined in this study through utilizing a sulfur source-tagging capability implemented in the Community Earth System Model (CESM) with winds nudged to reanalysis data. Sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO 2 emissions, the near-surface sulfate concentrations are primarily attributed to non-local sources from long-range transport. Regional source efficiencies of sulfate concentrations are higher over regions with dry atmospheric conditions and less export, suggesting that lifetime of aerosols, together with regional export, is important in determining regional air quality. The simulated global total sulfate DRF is −0.42 W m −2 , with −0.31 W m −2 contributed by anthropogenic sulfate and −0.11 W m −2 contributed by natural sulfate, relative to a state with no sulfur emissions. In the Southern Hemisphere tropics, dimethyl sulfide (DMS) contributes 17-84 % to the total DRF. East Asia has the largest contribution of 20-30 % over the Northern Hemisphere mid-and high latitudes. A 20 % perturbation of sulfate and its precursor emissions gives a sulfate incremental IRF of −0.44 W m −2 . DMS has the largest contribution, explaining −0.23 W m −2 of the global sulfate incremental IRF. Incremental IRF over regions in the Southern Hemisphere with low background aerosols is more sensitive to emission perturbation than that over the polluted Northern Hemisphere.

Sulfate Aerosol in the Arctic: Source Attribution and Radiative Forcing

“…The 20% emission reduction can lead to a larger warming effect contributed by East Asia than other source regions. Considering that the underestimation of China sulfate concentration by a factor of 2 in CAM5 (Yang, Wang, Smith, Easter, et al, ) may lead to an underestimation of sulfate transported from China to the Arctic, the warming effect from China emission reductions could be even stronger than our current estimates. A joint reduction in BC emissions could reduce the possible inadvertent Arctic warming from future SO 2 emission reductions.…”

“…Source attributions of Arctic sulfate and RFari for 2010–2014 are quantified using the CESM with a sulfur source‐tagging technique. Following a previous study (Yang, Wang, Smith, Easter, et al, ) that examined the global source‐receptor relationship of sulfate, 14 source regions and two natural sectors are tagged. The Arctic was generally defined as 66.5°N–90°N in this work.…”

African volcanic emissions influencing atmospheric aerosol particles over the Amazon rain forest

“…For this three-month period, estimated emissions were 0.81 Tg S and decreased in the following three months to 0.66 Tg S (Yang et al, 2017).…”

“…When the ITCZ shifts north in the dry season, south-east trade winds originating from southern Africa are more likely to reach the central Amazon rain forest. Even though the potential impact of transatlantic transport of volcanic sulfur emission has been suggested (Yang et al, 2017), no ground-based evidence has been reported previously in the literature concerning the impact of African volcanic sources.…”

E3SMv0‐HiLAT: A Modified Climate System Model Targeted for the Study of High‐Latitude Processes

“…After emission to the atmosphere, DMS is chemically oxidized to form SO 2 and other products, with a reactive lifetime on the order of one to several days. Over the Southern Ocean and other remote marine regions, DMS‐derived SO 2 is the most important source of CCN in the atmosphere (Carslaw et al, ; McCoy et al, ; Wang, Maltrud, Elliott, et al, ; Yang et al, ; Yang et al, ). These remote marine regions are particularly sensitive to changes in CCN number (Carslaw et al, ; Karydis et al, ; Moore, Karydis, et al, ); thus, it is necessary to adequately represent DMS emissions and DMS‐derived CCN in atmospheric models that simulate high‐latitude clouds.…”