Based on a series of experiments conducted by two regional climate models (RCA4 and LMDZ) with and without soil moisture-atmosphere coupling, we investigate the role of soil moisture on the occurrence of surface air temperature extremes and its persistence in Southeastern South America. Our analysis reveals that both factors, soil moisture-atmosphere coupling and relatively drier soil conditions, enhance the temperature extremes. In addition, the existence of soil-atmosphere coupling and the associated soil moisture variability is crucial for the development of the extremes in SESA. The key role of soil-atmosphere coupling is also reflected in the intrinsic persistence of hot days, which is greater in simulations with interactive soil moisture than in those with prescribed soil conditions. In the absence of soil-atmosphere coupling, the imprint of the anomalous dry (and also wet) soil conditions on the intensity and persistence of hot days is weaker.

基于两个区域气候模型（RCA4和LMDZ）在有和没有土壤水分-大气耦合的条件下进行的一系列实验，我们研究了土壤水分对南美洲东南部极端地面温度极端事件及其持久性的影响。我们的分析表明，土壤水分与大气的耦合以及相对干燥的土壤条件这两个因素都会加剧极端温度。此外，土壤-大气耦合的存在以及相关的土壤水分变异性对于SESA极端事件的发展至关重要。土壤与大气耦合的关键作用还体现在炎热天的固有持久性上，与交互作用的土壤水分模拟相比，在炎热的天气条件下模拟具有更大的持久性。在没有土壤-大气耦合的情况下，