发表机构
University of California, Irvine; Chapman University; University of California, Davis（加州大学欧文分校; 查普曼大学; 加州大学戴维斯分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分析2008-2024年加州蒸散数据，发现森林和农田在干旱中表现出相似的需求跟随，但分别依赖地下水和灌溉管理，揭示相似响应下隐藏的不同水分获取机制。
AI 中文摘要
大气变暖提高了蒸发需求，但实际蒸散（ETa）可能跟随需求，也可能在水资源限制下与需求脱钩。在此，我们通过回归斜率量化了2008-2024年间加利福尼亚全州去季节化ETa与参考蒸散（ETo）异常之间的需求跟随能力。森林和农田在严重干旱下保持了相似的正向跟随，而草地和灌木地则表现出较弱或负向的响应。尽管需求跟随相似，森林的响应与地下储水获取一致，而农田的响应则反映了管理性水分获取和作物系统的调整。活跃农田上的正向ETa-ETo耦合与全州范围内作物归属的休耕比例高于无干旱时期并存，表明仅基于活跃田块的估算未能捕捉整个作物系统的调整。在54.9%的网格单元中，后期需求跟随能力较低，区域性的更大下降伴随着更大的地下水储量损失。我们的结果表明，相似的ETa响应掩盖了不同的水分获取模式，在解释干旱响应时需要综合考虑水文和管理因素。
英文摘要
Atmospheric warming raises evaporative demand, but actual evapotranspiration (ETa) may track demand or decouple under water limitation. Here, we quantified demand-tracking ability from regression slopes relating deseasonalized ETa and reference evapotranspiration (ETo) anomalies across California during 2008-2024. Forests and croplands retained similar positive tracking under severe drought, whereas grasslands and shrublands showed weak or negative responses. Despite similar demand tracking, forest responses were consistent with subsurface-storage access, whereas cropland responses reflected managed water access and crop-system adjustment. Positive ETa-ETo coupling on active fields coexisted with a higher statewide crop-attributed fallow share of managed cropland than under no drought, showing that active-field estimates alone did not capture whole-crop-system adjustment. Late-period demand-tracking ability was lower at 54.9% of grid cells, with larger regional declines accompanying greater groundwater-storage losses. Our results indicate that similar ETa responses mask contrasting modes of water access, requiring joint consideration of hydrology and management when interpreting drought responses.
