近日，美国北卡罗来纳大学夏洛特分校Ian Chang团队揭示了低云日循环增强了区域气溶胶增温。相关论文发表在2025年7月17日出版的《自然—地球科学》杂志上。
大气气溶胶是地球气候系统的一个重要组成部分，对未来气候变化的预测造成很大的不确定性。在大西洋东南部，膨胀的吸光烟雾气溶胶羽流覆盖在半永久的层积云之上，直接气溶胶辐射效应（DARE）引起变暖，但这种效应的大小在气候模式之间差异很大。因此，有必要改进基于观测的估计，以帮助约束模型的不确定性。然
研究组基于每小时的云层卫星观测数据，采用辐射传输模型对云层辐射强迫（DARE）进行了量化分析，重点关注20°S–0°和10°W–15°E区域。结果发现，考虑东南大西洋观测到的云层日变化，而非假设整个下午早些时候的云场全天保持不变，会使区域平均气溶胶辐射增温增加两倍以上（+1.7±0.4 W m−2）。
DARE的增加源于早晨云量和光学厚度较高。在气候模型中，忽视云层日变化会导致低估东南大西洋的辐射增温，这与低估气溶胶吸收有关。未来基于观测的气溶胶气候效应估算需要考虑到云层日变化。
附：英文原文
Title: Regional aerosol warming enhanced by the diurnal cycle of low cloud
Author: Chang, Ian, Gao, Lan, Adebiyi, Adeyemi A., Doherty, Sarah J., Painemal, David, Smith, William L., Lenhardt, Emily D., Fakoya, Abdulamid A., Flynn, Connor J., Zheng, Jianyu, Yang, Zhifeng, Castellanos, Patricia, da Silva, Arlindo M., Zhang, Zhibo, Wood, Robert, Zuidema, Paquita, Christopher, Sundar A., Redemann, Jens
Issue&Volume: 2025-07-17
Abstract: Atmospheric aerosols are an important component of the Earth’s climate system and contribute substantial uncertainties to predictions of future climate change. In the southeast Atlantic, where expansive light-absorbing smoke aerosol plumes overlie semi-permanent stratocumulus clouds, the direct aerosol radiative effect (DARE) induces warming, but the magnitude of this effect varies widely among climate models. Thus, it is essential to improve estimates based on observations to help constrain model uncertainties. However, the impact of the observed cloud diurnal cycle on DARE remains unclear. Here we quantify DARE using radiative transfer modelling based on hourly satellite observations of clouds focusing on the region 20°S–0° and 10°W–15°E. We find that accounting for the observed cloud diurnal cycle over the southeast Atlantic, rather than assuming a constant early-afternoon cloud field throughout the entire day, results in a more than twofold increase (+1.7±0.4Wm2) in the regional mean aerosol radiative warming. The increase in DARE results from morning hours when cloud fractions and optical depths are higher. Neglect of the cloud diurnal cycle adds to the underestimated radiative warming in the southeast Atlantic associated with underestimated aerosol absorption among climate models. Future observations-based estimates of aerosol climatic effects need to account for the cloud diurnal cycle.
DOI: 10.1038/s41561-025-01740-1
Source: https://www.nature.com/articles/s41561-025-01740-1