近日，美国航空航天局兰利研究中心Norman G. Loeb团队揭示了地球辐射出现半球不对称。这一研究成果发表在2025年9月29日出版的《美国科学院院刊》杂志上。

来自"云与地球辐射能量系统"长达24年的卫星观测数据显示：在吸收太阳辐射方面，北半球与南半球之间的趋势差异达到每十年0.34±0.23瓦/平方米（5%至95%置信区间）；而在向外长波辐射方面，趋势差异较弱，为每十年0.21±0.21瓦/平方米。北半球相对南半球逐渐变暗的现象，与半球间气溶胶-辐射相互作用、地表反照率及水蒸气变化的差异密切相关。

云层变化也会加剧吸收太阳辐射的半球差异，但由于热带和温带地区趋势差异相互抵消，其影响幅度较小。吸收太阳辐射的半球对称性破缺，挑战了"云层会自然补偿非云特性受迫性半球不对称"的传统认知。辐射能量的半球对称性破缺与大气-海洋环流密切相关，而云层如何应对这种半球能量失衡对未来气候演变具有重要影响。

附：英文原文

Title: Emerging hemispheric asymmetry of Earth’s radiation

Author: Loeb, Norman G., Thorsen, Tyler J., Kato, Seiji, Rose, Fred G., Hodnebrog, ivind, Myhre, Gunnar

Issue&Volume: 2025-9-29

Abstract: Twenty-four years of satellite observations from the Clouds and the Earth’s Radiant Energy System show a northern hemisphere (NH) minus southern hemisphere (SH) trend difference of 0.34 ± 0.23 Wm2 dec1 (5 to 95% CI) in absorbed solar radiation (ASR) and a weaker trend difference of 0.21 ± 0.21 Wm2 dec1 in outgoing longwave radiation. The emerging darkening of the NH relative to the SH is associated with changes in hemispheric differences in aerosol–radiation interactions, surface albedo, and water vapor changes. Cloud changes also contribute to a greater ASR hemispheric contrast, but the magnitude is small due to opposing trend differences in the tropics and extratropics. The break in hemispheric symmetry in ASR challenges the notion that clouds naturally compensate for forced hemispheric asymmetries in noncloud properties. Hemispheric (a)symmetry in radiation is linked with the atmosphere–ocean general circulation. How clouds respond to this hemispheric imbalance has important implications for future climate.

DOI: 10.1073/pnas.2511595122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2511595122