The coupling of soil moisture to climatic variables highly depends on soil moisture variability. Therefore, the activities affecting the soil moisture availability and dynamics such as land use/cover change and agricultural practices influence land-atmosphere interactions. Using soil moisture proxies, modeling studies have proven significant coupling of soil water variations to near-surface atmospheric temperature in some regions. However, these works have mostly applied the precipitation-based indices at a specific time scale. In the present study, the concurrent and lagged associations of the soil wetness variations and the high temperature index (HTI) across different climates in Iran were evaluated using Spearman’s rank test. Standardized precipitation index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) calculated at one-month and six-month scales were employed as soil moisture surrogates. When seasonal aridity index (AI) range was from 0.2 to 1.0 (transitional condition), SPEI1 and SPI1 were correlated significantly (p < 0.05) with HTI at 83.0 and 42.4 % of cases, respectively. However, when AI was below 0.2 (water-limited condition) or over 2.0 (energy-limited condition), the topsoil moisture indices showed an insignificant association with HTI at the majority of cases. A significant negative association existed between SPEI6 and HTI at most dry cases in which soil surface is dry but subsoil appears not to be fully depleted. Therefore, the topsoil and subsoil moisture variations are likely to affect high temperature occurrence under transitional and dry conditions, respectively. The insignificant lagged correlations found for most areas indicate poor linear relationship between high temperature occurrence and soil water dynamics in the preceding month over the study area. Furthermore, when AI exceed 0.2, ENSO-related soil drought is likely to cause a stronger soil moisture-temperature coupling. Overall, the role of evapotranspiration and soil moisture depth should be considered for assessing soil moisture dynamics and land-atmosphere interactions. Our findings may be helpful for adopting soil moisture-based adaptive measures to negate the impacts of high temperatures on agricultural products.

土壤水分与气候变量的耦合高度依赖于土壤水分的变异性。因此，影响土壤水分可用性和动态的活动，如土地利用/覆盖变化和农业实践，会影响土地-大气相互作用。使用土壤水分代理，建模研究已证明在某些地区土壤水分变化与近地表大气温度之间存在显着耦合。然而，这些工作大多应用了特定时间尺度的基于降水的指数。在本研究中，伊朗不同气候下土壤湿度变化和高温指数 (HTI) 的同步和滞后关联使用 Spearman 等级检验进行评估。以 1 个月和 6 个月为尺度计算的标准化降水指数 (SPI) 和标准化降水蒸散指数 (SPEI) 被用作土壤水分替代指标。当季节性干旱指数（AI）范围为 0.2 到 1.0（过渡条件）时，SPEI1 和 SPI1 显着相关（磷 < 0.05)，HTI 分别为 83.0 % 和 42.4 % 的病例。然而，当 AI 低于 0.2（水限制条件）或超过 2.0（能量限制条件）时，在大多数情况下，表土水分指数与 HTI 的关联不显着。在土壤表面干燥但底土似乎没有完全耗尽的大多数干燥情况下，SPEI6 和 HTI 之间存在显着的负相关。因此，表土和底土水分变化可能分别影响过渡和干燥条件下的高温发生。大多数地区发现的不显着的滞后相关性表明研究区上个月高温发生与土壤水动力学之间的线性关系较差。此外，当 AI 超过 0.2 时，ENSO 相关的土壤干旱可能导致更强的土壤水分-温度耦合。总体而言，在评估土壤水分动态和陆地-大气相互作用时，应考虑蒸散和土壤水分深度的作用。我们的研究结果可能有助于采用基于土壤水分的适应性措施来抵消高温对农产品的影响。