Zhong Ziqian, Chen Hans W, Dai Aiguo, Zhou Tianjun, He Bin, Su Bo
Department of Space, Earth and Environment, Division of Geoscience and Remote Sensing, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA.
Nat Commun. 2025 Sep 9;16(1):8247. doi: 10.1038/s41467-025-63672-z.
Rising atmospheric vapor pressure deficit (VPD)-a measure of atmospheric dryness, defined as the difference between saturated vapor pressure (SVP) and actual vapor pressure (AVP)-has been linked to increasing daily mean near-surface air temperatures since the 1980s. However, it remains unclear whether the faster increases in daily maximum temperature (T) relative to daily minimum temperature (T) have contributed to rising VPD. Here, we show that the faster rise in T compared with T over land has intensified VPD from 1980 to 2023. This sub-diurnal asymmetric warming has driven a larger SVP increase than would occur under uniform temperature rise, while AVP is more strongly influenced by T. Using reanalysis data, we estimate that asymmetric warming has contributed an additional ~18% to the increase in global land VPD. Sub-daily station observations corroborate this pattern, with asymmetric warming accounting for ~30% of VPD intensification across all stations. Our findings indicate that sub-diurnal asymmetric warming has substantially amplified global warming's effect on atmospheric dryness over the past four decades, with significant implications for terrestrial water availability and carbon cycling.
大气水汽压亏缺（VPD）上升——一种衡量大气干燥程度的指标，定义为饱和水汽压（SVP）与实际水汽压（AVP）之差——自20世纪80年代以来一直与日平均近地表气温上升相关。然而，日最高气温（T）相对于日最低气温（T）的更快上升是否导致了VPD上升仍不清楚。在此，我们表明，1980年至2023年期间，陆地T相对于T的更快上升加剧了VPD。这种次昼夜不对称变暖导致的饱和水汽压上升幅度大于均匀升温情况下的上升幅度，而实际水汽压受最低气温的影响更大。利用再分析数据，我们估计不对称变暖对全球陆地VPD增加的贡献额外约为18%。次日站点观测证实了这一模式，不对称变暖占所有站点VPD加剧的约30%。我们的研究结果表明，在过去四十年中，次昼夜不对称变暖极大地放大了全球变暖对大气干燥程度的影响，对陆地水资源可用性和碳循环具有重大意义。
