Decadal trends in surface solar radiation and cloud cover over the North Atlantic sector during the last four decades: drivers and physical processes
Decadal trends in surface solar radiation and cloud cover over the North Atlantic sector during the last four decades: drivers and physical processes
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DOI：
10.1007/s00382-022-06438-3
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发表时间：
2022-08
期刊：
影响因子：
4.6
通讯作者：
B. Dong;R. Sutton;L. Wilcox
中科院分区：
文献类型：
--
作者：
B. Dong;R. Sutton;L. Wilcox
卫星产品和再分析显示，从 20 世纪 80 年代到 2010 年代，北美和欧洲的表面太阳辐射 (SSR) 持续增加，云量减少。这些趋势显示出很强的季节性，其中北方夏季变化最大。使用大气环流模型（AGCM）进行了一组时间片实验，强制规定了海面温度/海冰范围（SST/SIE）、温室气体（GHG）浓度和人为气溶胶（AA）排放量的变化，同时或单独进行，以评估不同强迫在这些观测到的趋势中的相对作用。该模型再现了欧洲和北美观察到的主要特征，包括趋势的季节性，表明强迫变化在 SSR 和云量的近期趋势中起主导作用。对个别强迫的响应表明，欧洲 SSR 的最近十年趋势主要是由 AA 减排驱动的，另外还有 SST/SIE 和 GHG 变化的影响。相比之下，尽管 SST/SIE 发挥着最重要的作用，但 AA、SST/SIE 和 GHG 的变化对模拟的 SSR 和北美云量十年趋势的贡献更为均等。在我们的模拟中，SSR 对 AA 减排的响应主要受气溶胶-辐射相互作用的影响。对 SST/SIE 和 GHG 变化的响应主要是由于大气环流和湿度变化驱动的云量变化。这种对不同强迫因素如何影响 SSR 和云量的十年趋势的过程水平理解对于理解全球和区域地表能源预算、地表变暖以及全球和区域水文循环的过去变化和未来预测很有价值。
Satellite-derived products and reanalyses show consistent increases in downward surface solar radiation (SSR) and decreases in cloud cover over North America and Europe from the 1980s to 2010s. These trends show a strong seasonality, with the largest changes in boreal summer. A set of timeslice experiments with an atmospheric general circulation model (AGCM) forced with prescribed changes in sea surface temperature/sea ice extent (SST/SIE), greenhouse gas (GHG) concentrations, and anthropogenic aerosol (AA) emissions, together and separately, is performed to assess the relative roles of different forcings in these observed trends. The model reproduces the main observed features over Europe and North America, including the seasonality of trends, suggesting a dominant role of forced changes in the recent trends in SSR and cloud cover. Responses to individual forcings indicate that recent decadal trends in SSR over Europe are predominantly driven by AA emission reductions, with an additional influence from SST/SIE and GHG changes. In contrast, changes in AA, SST/SIE, and GHG contribute more equally to simulated decadal trends in SSR and cloud cover over North America, although SST/SIE play the most important role. In our simulations, responses of SSR to AA emission reductions are primarily governed by aerosol-radiation interactions. Responses to SST/SIE and GHG changes are predominantly due to cloud cover changes, which are driven by atmospheric circulation and humidity changes. This process level understanding of how different forcing factors influence decadal trends in SSR and cloud cover is valuable for understanding past changes and future projections in global and regional surface energy budgets, surface warming, and global and regional hydrological cycles.