近日，北京大学赵传峰团队研究了2000至2022年北极夏季云变化趋势及其潜在原因。该项研究成果发表在2025年3月17日出版的《中国科学：地球科学》杂志上。

北极的气候变化是全球气候系统变化的关键指标，云在调节北极地表辐射能平衡方面发挥着至关重要的作用。阐明北极云变化的模式和潜在机制对于理解北极气候变化具有至关重要的科学意义。对北极云特征的时空分析表明，自21世纪初以来，低云主要由北极夏季云组成（约60%），其次是中云（约30%）。总云量呈明显上升趋势，特别是在波弗特海和楚科奇海（0.45%/年）。

归因分析表明，北极云量的变化主要由两种大气环流模式的趋势驱动：北极涛动（AO）和北极偶极子异常（DA）。在AO的正相位期间，所有北极盆地的云分数都在增加。相反，在DA的正相位，波弗特海、楚科奇海和格陵兰海的云分数降低，而东西伯利亚海、喀拉海和巴伦支海的云比率增加，表明“东西”偶极子分布。自2000年以来，AO一直呈上升趋势，而DA一直在下降。

这两种模式的共同作用导致波弗特海地区云量显著增加。对云辐射效应的进一步研究表明，云分数的增加加剧了长波变暖和短波冷却效应，导致整体净负辐射效应。分析北极夏季云层的长期趋势可以增强我们对北极气候变化的理解。

附：英文原文

Title: Trends in Arctic summer cloud variability from 2000 to 2022 and the potential causes

Author: Haotian ZHANG, Chuanfeng ZHAO, Annan CHEN, Yikun YANG, Jiefeng LI, Xin ZHAO, Yue ZHOU, Hao FAN

Issue&Volume: 2025/03/17

Abstract: Climate change in the Arctic serves as a pivotal indicator of alterations in the global climate system, with clouds playing an essential role in regulating the surface radiative energy balance in the Arctic. Elucidating the patterns of Arctic cloud variability and the underlying mechanisms is of paramount scientific importance for understanding Arctic climate change. Spatiotemporal analysis of Arctic cloud characteristics reveals that since the onset of the 21st century, low clouds have predominantly comprised the Arctic summer cloud fraction (approximately 60%), followed by middle clouds (approximately 30%). The total-cloud fraction has exhibited a marked increasing trend, especially in the Beaufort Sea and Chukchi Sea (0.45%/yr). An attribution analysis suggests that the changes in the Arctic cloud fraction are chiefly driven by trends in two atmospheric circulation modes: The Arctic Oscillation (AO) and the Arctic dipole anomaly (DA). During positive phases of the AO, the cloud fraction increases across all Arctic basins. Conversely, in the positive phases of the DA, the cloud fraction decreases in the Beaufort Sea, Chukchi Sea, and Greenland Sea, whereas it increases in the East Siberian Sea, Kara Sea, and Barents Sea, indicating an “east-west” dipole distribution. Since 2000, the AO has been on an upward trend, whereas the DA has been declining. The combined effect of these two modes has resulted in a significant increase in the cloud fraction within the Beaufort Sea region. Further examination of cloud radiative effects indicates that an increase in the cloud fraction intensifies both longwave warming and shortwave cooling effects, leading to an overall net negative radiative effect. Analyzing the long-term trends in Arctic summer clouds enhances our comprehension of Arctic climate change.

DOI: 10.1007/s11430-024-1523-5

Source: https://www.sciengine.com/SCES/doi/10.1007/s11430-024-1523-5