近日，以色列希伯来大学 Dagan, Guy 及其团队在研究受大尺度环流调整增强的气溶胶—云相互作用辐射力中取得新进展。2023年11月20日，《自然—地球科学》期刊发表了这一成果。

为了解决这个问题，该团队研究人员在狭长区域进行的允许对流的模拟，同时还包括大规模过程的表示来解决对流问题。研究人员进行了一组包含海洋表面温度梯度(驱动了大规模环流)的模拟，并将这些模拟与不包含梯度的模拟进行了比较。研究表明，气溶胶—云相互作用的有效辐射力通过大尺度环流对气溶胶的调整而大大增强。

研究结果表明，气溶胶浓度的增加抑制了浅对流区域的降水，从而增强了水汽向深对流主导区域的输送。随后在深层对流区潜热释放的增加，加强了翻转环流和地表蒸发。这些变化可以解释为在较高气溶胶浓度下云量的增加，以及由此产生的较大的气溶胶辐射效应。研究结果强调了大尺度环流调整，在理解气溶胶—云相互作用的有效辐射力方面的基本重要性。

据了解，在估计人类活动对气候系统的影响时，人为气溶胶对云的影响是不确定性的主要来源。挑战在于云（约 1 到 10km）大气环流和气候（大于1,000 km）之间的尺度差异。

附：英文原文

Title: Radiative forcing from aerosol–cloud interactions enhanced by large-scale circulation adjustments

Author: Dagan, Guy, Yeheskel, Netta, Williams, Andrew I. L.

Issue&Volume: 2023-11-20

Abstract: The impact of anthropogenic aerosols on clouds is a leading source of uncertainty in estimating the effect of human activity on the climate system. The challenge lies in the scale difference between clouds (~1–10km) and general circulation and climate (>1,000km). To address this, we use convection-permitting simulations conducted in a long and narrow domain, to resolve convection while also including a representation of large-scale processes. We examine a set of simulations that include a sea surface temperature gradient—which drives large-scale circulation—and compare these with simulations that include no gradient. We show that the effective radiative forcing due to aerosol–cloud interactions is strongly enhanced by adjustments of large-scale circulation to aerosol. We find that an increase in aerosol concentration suppresses precipitation in shallow-convective regions, which enhances water vapour transport to the portion of the domain dominated by deep convection. The subsequent increase in latent heat release in deep-convective regions strengthens the overturning circulation and surface evaporation. These changes can explain the increase in cloudiness under higher aerosol concentrations and, consequently, the large aerosol radiative effect. This work highlights the fundamental importance of large-scale circulation adjustments in understanding the effective radiative forcing from aerosol–cloud interactions.

DOI: 10.1038/s41561-023-01319-8

Source: https://www.nature.com/articles/s41561-023-01319-8