德国马克斯普朗克气象研究所
研究人员回顾了土壤水分—降水反馈的全球耦合模拟，并进行了1年的显式对流模拟，将结果与参数化对流的粗分辨率模拟结果进行了比较。结果显示，在大多数反馈较弱的点上存在显著的差异，主要是显式对流的负反馈。与粗分辨率模式相比，具有显对流的模型更经常处于潮湿状态，并且在土壤湿度不均匀的情况下，更倾向于在干燥土壤上触发对流。
进一步分析表明，土壤水分与蒸散发之间以及蒸散发与降水之间的反馈都较弱，与观测结果相吻合。研究结果强调，粗分辨率模型可能不太适合研究陆地气候变化的特定部分，例如干旱和热浪的变化。
据了解，关于土壤水分—降水反馈信号的争论仍然存在。一方面，以全球粗分辨率气候模型的研究发现了强烈的正反馈。然而，这种模型不能明确地表示对流。另一方面，以千米尺度区域气候模式和显对流的研究报告了负反馈。然而，这种模式规定了大规模的循环。
附：英文原文
Title: Weaker land–atmosphere coupling in global storm-resolving simulation
Author: Lee, Junhong, Hohenegger, Cathy
Issue&Volume: 2024-3-12
Abstract: The debate on the sign of the soil moisture–precipitation feedback remains open. On the one hand, studies using global coarse-resolution climate models have found strong positive feedback. However, such models cannot represent convection explicitly. On the other hand, studies using km-scale regional climate models and explicit convection have reported negative feedback. Yet, the large-scale circulation is prescribed in such models. This study revisits the soil moisture–precipitation feedback using global, coupled simulations conducted for 1 y with explicit convection and compares the results to coarse-resolution simulations with parameterized convection. We find significant differences in a majority of points with feedback that is weaker and dominantly negative with explicit convection. The model with explicit convection is more often in a wet regime and prefers the triggering of convection over dry soil in the presence of soil moisture heterogeneity, in contrast to the coarse-resolution model. Further analysis indicates that the feedback not only between soil moisture and evapotranspiration but also between evapotranspiration and precipitation is weaker, in better agreement with observations. Our findings suggest that coarse-resolution models may not be well suited to study aspects of climate change over land such as changes in droughts and heatwaves.
DOI: 10.1073/pnas.2314265121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2314265121