Entrainment Makes Pollution More Likely to Weaken Deep Convective Updrafts Than Invigorate Them
Entrainment Makes Pollution More Likely to Weaken Deep Convective Updrafts Than Invigorate Them
复制标题
DOI：
10.1029/2023gl103314
复制
发表时间：
2023-06
影响因子：
5.2
通讯作者：
J. Peters;Z. Lebo;D. Chavas;Chun‐Yian Su
中科院分区：
文献类型：
--
作者：
J. Peters;Z. Lebo;D. Chavas;Chun‐Yian Su
忽略卷吸的气溶胶激发研究结果对稀释的深对流云有效吗？我们通过将卷吸包裹模式应用于热带和中纬度对流环境的探测来解决这个问题，其中假定污染会增加包裹冷凝物的滞留。当冰冻迅速时，未稀释的热带和中纬度的地块可以分别增加5%-10%和2%的活力。这是因为冻结的正浮力贡献大于凝析油装载的负浮力贡献，从而导致净凝析油对浮力的正贡献。然而，当实际的夹带速率出现时，气溶胶诱导的减弱更有可能发生，因为夹带的水分损失比负荷贡献更显著地减少了潜热。这导致在污染的包裹中凝析油的净负浮力贡献比在清洁包裹中的更大。我们的结果表明，在深对流中气溶胶间接效应的概念模型中，考虑夹带是至关重要的。
Are the results of aerosol invigoration studies that neglect entrainment valid for diluted deep convective clouds? We address this question by applying an entraining parcel model to soundings from tropical and midlatitude convective environments, wherein pollution is assumed to increase parcel condensate retention. Invigoration of 5%–10% and <2% is possible in undiluted tropical and midlatitude parcels respectively when freezing is rapid. This occurs because the positive buoyancy contribution from freezing is larger than the negative buoyancy contribution from condensate loading, leading to positive net condensate contribution to buoyancy. However, aerosol‐induced weakening is more likely when realistic entrainment rates occur because water losses from entrainment more substantially reduce the latent heating relative to the loading contribution. This leads to larger net negative buoyancy contribution from condensates in polluted than in clean entraining parcels. Our results demonstrate that accounting for entrainment is critical in conceptual models of aerosol indirect effects in deep convection.