近日，美国科罗拉多大学博尔德分校Jianhao Zhang团队报道了地球的东西反照率对称。该研究于2026年6月3日发表在《自然》杂志上。

地球的反照率对行星能量收支至关重要。北半球（NH）和南半球（SH）对行星反照率的贡献基本相等——这是一种显著而令人困惑的现象，被称为半球反照率对称性。尽管这种对称性罕见，但并非唯一。然而，其他对称对尚未得到探索，尽管它们有可能揭示反照率对称性的可能成因及其对行星能量收支的影响。

利用25年的卫星观测记录，研究组揭示了地球还表现出一种独特且持久的东-西（E–W）反照率对称性：东经27°经线将地球划分为东半球（EH）和西半球（WH），两者反射的太阳光量几乎相同。与南北半球对称性不同，东西半球对称性体现了一种独特的“三重对称性”：晴空反照率、云辐射效应和开阔海洋占比都围绕这条经线呈现出半球对称性。这种东西半球对称性源于东半球更多的高云反射与西半球更多的低云反射之间的平衡。

此外，东西半球对称性的年际变化与厄尔尼诺-南方涛动（ENSO）的位相变化一致，表明其与大气环流存在潜在联系。东西半球反照率对称性及其作为三重对称性的发现，为地球系统模型（ESM）提供了一个降自由度约束，并强调了在气候快速变化的背景下持续观测地球辐射收支的至关重要性。

附：英文原文

Title: Earth’s east–west albedo symmetry

Author: Zhang, Jianhao, Gristey, Jake J., Feingold, Graham

Issue&Volume: 2026-06-03

Abstract: Earth’s albedo is fundamental to the planetary energy budget1. The Northern Hemisphere (NH) and Southern Hemisphere (SH) contribute essentially equally to the planetary albedo—a remarkable yet puzzling phenomenon known as hemispheric albedo symmetry1,2,3,4,5,6. Although such symmetry is rare, it is not unique7. Nevertheless, other symmetry pairs have remained unexplored, despite their potential to illuminate possible causes of albedo symmetries and implications for the planetary energy budget. Using a 25-year satellite record, here we show that Earth also exhibits a unique and persistent east–west (E–W) albedo symmetry: the 27°E meridian divides the planet into an Eastern Hemisphere (EH) and a Western Hemisphere (WH) that reflect nearly identical amounts of sunlight. In contrast to the NH–SH symmetry, the EH–WH symmetry encapsulates a distinctive ‘triple symmetry’ in which clear-sky albedo, cloud radiative effect and open-ocean fraction all exhibit hemispheric symmetry around this meridian. This EH–WH symmetry arises from greater high-cloud reflection in the EH balancing greater low-cloud reflection in the WH. Furthermore, interannual variability in the EH–WH symmetry tracks the phase of the El Nio–Southern Oscillation (ENSO), indicating a potential connection to general circulation. This discovery of the EH–WH albedo symmetry and its emergence as a triple symmetry provides a reduced degree-of-freedom constraint for Earth system models (ESMs) and stresses the critical nature of continued Earth radiation budget observations under a rapidly changing climate.

DOI: 10.1038/s41586-026-10624-2

Source: https://www.nature.com/articles/s41586-026-10624-2