Impact of Soil Moisture-Atmosphere Interactions on Surface Temperature Distribution
Impact of Soil Moisture-Atmosphere Interactions on Surface Temperature Distribution
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DOI：
10.1175/jcli-d-13-00591.1
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发表时间：
2014-11-01
影响因子：
4.9
通讯作者：
Gentine, Pierre
中科院分区：
文献类型：
--
作者：
Berg, Alexis;Lintner, Benjamin R.;Gentine, Pierre
了解不同的物理过程如何塑造表面温度的概率分布函数（PDF），特别是分布的尾部，对于未来极端温度事件的归因和预测至关重要。在这项研究中，土壤水分-大气相互作用对地表温度PDF的贡献进行了研究。土壤湿度是陆地和大气耦合的一个关键变量，因为它控制着地表感热通量和潜热通量之间可用能量的分配。因此，由大气驱动的土壤湿度变化可能会反馈到近地表气候，特别是温度。在这项研究中，两个模拟的当前一代地球物理流体动力学实验室（GFDL）地球系统模型，有和没有互动的土壤水分，进行了分析，以评估土壤水分动态如何影响模拟气候。这些模拟的比较表明，土壤水分动力学提高了温度的平均值和方差在区域“热点”的陆气耦合。此外，高阶分布矩，如偏度和峰度，也受到显着影响，这表明对温度PDF的正负极端的非对称影响。这样的变化被解释的上下文中改变的表面湍流和辐射通量的分布。温度分布的时刻可能会对土壤水分动力学做出不同的反应，这强调了分析超越均值和方差的时刻的重要性，以充分表征土壤水分和近地表温度的相互作用。此外，它表明，土壤水分动力学影响日温度变率在不同的时间尺度上在不同的区域模型。
Understanding how different physical processes can shape the probability distribution function (PDF) of surface temperature, in particular the tails of the distribution, is essential for the attribution and projection of future extreme temperature events. In this study, the contribution of soil moisture-atmosphere interactions to surface temperature PDFs is investigated. Soil moisture represents a key variable in the coupling of the land and atmosphere, since it controls the partitioning of available energy between sensible and latent heat flux at the surface. Consequently, soil moisture variability driven by the atmosphere may feed back onto the near-surface climate-in particular, temperature. In this study, two simulations of the current-generation Geophysical Fluid Dynamics Laboratory (GFDL) Earth System Model, with and without interactive soil moisture, are analyzed in order to assess how soil moisture dynamics impact the simulated climate. Comparison of these simulations shows that soil moisture dynamics enhance both temperature mean and variance over regional "hotspots" of land atmosphere coupling. Moreover, higher-order distribution moments, such as skewness and kurtosis, are also significantly impacted, suggesting an asymmetric impact on the positive and negative extremes of the temperature PDF. Such changes are interpreted in the context of altered distributions of the surface turbulent and radiative fluxes. That the moments of the temperature distribution may respond differentially to soil moisture dynamics underscores the importance of analyzing moments beyond the mean and variance to characterize fully the interplay of soil moisture and near-surface temperature. In addition, it is shown that soil moisture dynamics impacts daily temperature variability at different time scales over different regions in the model.