Jacobson Mark Z
Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305-4020, USA.
J Phys Chem A. 2006 Jun 1;110(21):6860-73. doi: 10.1021/jp056391r.
This paper examines the incremental global climate response of black carbon (BC), the main component of soot, due to absorption and scattering by BC inclusions within cloud and precipitation particles. Modeled soot is emitted as an externally mixed aerosol particle. It evolves to an internal mixture through condensation, hydration, dissolution, dissociation, crystallization, aqueous chemistry, coagulation, and cloud processing. Size-resolved cloud liquid and ice particles grow by condensation onto size-resolved soot and other particles. Cloud particles grow to precipitation by coagulation and the Bergeron process. Cloud and precipitation particles also undergo freezing, melting, evaporation, sublimation, and coagulation with interstitial aerosol particles. Soot, which is tracked in cloud and precipitation particles of all sizes, is removed by rainout, washout, sedimentation, and dry deposition. Two methods of treating the optics of BC in size-resolved cloud liquid, ice and graupel are compared: the core-shell approximation (CSA) and the iterative dynamic effective medium approximation (DEMA). The 10-year global near-surface incremental temperature response due to fossil fuel (ff), biofuel (bf), and biomass burning (bb) BC within clouds with the DEMA was slightly stronger than that with the CSA, but both enhancements were <+0.05 K. The ff+bf portion may be approximately 60% of the total, suggesting that BC inclusions within clouds may enhance the near-surface temperature response of ff+bf soot due to all processes (estimated as approximately 0.27 K), by <10%, strengthening the possible climate impact of BC. BC cloud absorption was also found to increase water vapor, decrease precipitation, and decrease cloud fraction. The increase in water vapor at the expense of precipitation contributed to warming in addition to that of the cloud BC absorption itself. Aerosol-hydrometeor coagulation followed by hydrometeor evaporation may have caused almost twice the BC internal mixing as aerosol-aerosol coagulation.
本文研究了煤烟的主要成分黑碳（BC）由于云粒子和降水粒子中BC夹杂物的吸收和散射而产生的全球气候增量响应。模拟的煤烟以外部混合气溶胶粒子的形式排放。它通过凝结、水合、溶解、离解、结晶、水相化学、凝聚和云处理演变为内部混合物。按粒径分辨的云液态水和冰粒子通过凝结在按粒径分辨的煤烟和其他粒子上而增长。云粒子通过凝聚和贝吉隆过程增长为降水。云粒子和降水粒子还会经历冻结、融化、蒸发、升华以及与间隙气溶胶粒子的凝聚。在所有粒径的云粒子和降水粒子中追踪的煤烟，通过雨除、冲刷、沉降和干沉降被去除。比较了两种处理按粒径分辨的云液态水、冰和霰中BC光学性质的方法：核壳近似（CSA）和迭代动态有效介质近似（DEMA）。使用DEMA时，化石燃料（ff）、生物燃料（bf）和生物质燃烧（bb）BC在云中导致的10年全球近地表增量温度响应略强于使用CSA时，但两种增强均<+0.05K。ff+bf部分可能约占总量的60%，这表明云中的BC夹杂物可能使ff+bf煤烟由于所有过程导致的近地表温度响应增强（估计约为0.27K），增幅<10%，从而加强了BC可能的气候影响。还发现BC云吸收会增加水汽、减少降水并降低云量分数。以降水为代价增加的水汽除了云BC吸收本身导致的变暖外，还促成了变暖。气溶胶 - 水凝物凝聚随后水凝物蒸发可能导致的BC内部混合几乎是气溶胶 - 气溶胶凝聚的两倍。
