Prior research indicates that land use and land cover change (LULCC) in the central United States has led to significant changes in surface climate. The spatial resolution of simulations is particularly relevant in this region due to its influence on model skill in capturing mesoscale convective systems (MCSs) and on representing the spatial heterogeneity. Recent advances in Earth system models (ESMs) make it feasible to use variable resolution (VR) meshes to study regional impacts of LULCC while avoiding inconsistencies introduced by lateral boundary conditions typically seen in limited area models. Here, we present numerical experiments using the Community Earth System Model version 2–VR to evaluate (1) the influence of resolution and land use on model skill and (2) impacts of LULCC over the central United States at different resolutions. These simulations are configured either on the 1° grid or a VR grid with grid refinement to 1/8° over the contiguous United States for the period of 1984–2010 with two alternative land use data sets corresponding to the preindustrial and present day states. Our results show that skill in simulating precipitation over the central United States is primarily dependent on resolution, whereas skill in simulating 2‐m temperature is more dependent on accurate land use. The VR experiments show stronger LULCC‐induced precipitation increases over the Midwest in May and June, corresponding to an increase in the number of MCS‐like features and a more conductive thermodynamic environment for convection. Our study demonstrates the potential of using VR ESMs for hydroclimatic simulations in regions with significant LULCC.

中文翻译：

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CESM2-VR中美国中部的土地利用和土地覆被变化强烈调节着土地-大气耦合和暖季降水

先前的研究表明，美国中部的土地利用和土地覆被变化（LULCC）导致了地表气候的重大变化。由于该空间模拟对捕获中尺度对流系统（MCS）的模型技能以及表示空间异质性的影响，因此该区域的模拟空间分辨率特别重要。地球系统模型（ESM）的最新进展使得使用可变分辨率（VR）网格来研究LULCC的区域影响变得可行，同时避免了通常在有限区域模型中看到的横向边界条件带来的不一致。在这里，我们使用社区地球系统模型版本2–VR进行数值实验，以评估（1）分辨率和土地使用对模型技能的影响，以及（2）LULCC在美国中部以不同分辨率的影响。在1984-2010年期间，可以在1°网格或VR网格上对这些模拟进行配置，并在连续的美国范围内将网格细化到1/8°，并使用两个替代的土地利用数据集，分别对应于工业化之前和当今的状态。我们的结果表明，模拟美国中部地区降水的技能主要取决于分辨率，而模拟2米温度的技能则更多取决于准确的土地利用。VR实验表明，5月和6月中西部地区LULCC引起的降水增加，这与MCS特征的数量增加以及对流的热传导环境更为传导有关。我们的研究表明，在具有重大LULCC的地区，使用VR ESM进行水气候模拟的潜力。