Quantifying the local and remote impacts of sub-grid physical processes on the Southeast Pacific sea surface fluxes in the Community Atmosphere Model version 5 by a limited-area parameter perturbation approach
Quantifying the local and remote impacts of sub-grid physical processes on the Southeast Pacific sea surface fluxes in the Community Atmosphere Model version 5 by a limited-area parameter perturbation approach
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通过有限区域参数扰动方法量化社区大气模型版本 5 中子网格物理过程对东南太平洋海面通量的本地和远程影响
DOI：
10.1002/joc.7308
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发表时间：
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影响因子：
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通讯作者：
Zhang Yaocun
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作者：
Liu Shujun;Yang Ben;Guo Zhun;Wang Minghuai;Qian Yun;Huang Anning;Zhang Yaocun
东南太平洋（SEP）具有明显的气候特征，受多个空间尺度过程相互作用的控制，因此很难在气候模式中进行描述。本研究探讨了本地和远程的各种物理过程的影响，在SEP的地面通量在社区大气模式版本5通过使用有限区域参数摄动方法。在该方法中，张-麦克法兰（ZM）对流方案和湍流参数化方案的云层统一的Binormals（CLUBB）的物理参数在特定的区域扰动，但外部固定。分别在SEP、热带辐合带（ITCZ）和南太平洋辐合带（SPCZ）上进行了三个有限区域扰动参数集合，其中SEP是主要的模拟重点，可以响应来自ITCZ和SPCZ的本地影响和远程影响。结果表明，地面辐射通量的变化主要是由次网格物理过程的局地影响所解释的，其中与浅层对流有关的影响最为重要。与此相反，相当一部分的地面潜热通量的变化归因于ITCZ和SPCZ的远程效应，这主要是由ZM参数，可以影响大尺度环流，通过调制非绝热加热有关的降水。随着东ITCZ降水的增加，东南太平洋上空的潜热通量和短波辐射通量都增加，这分别是由于地面风强和云少的缘故。总的来说，我们的研究结果有助于更好地了解模拟SEP气候的不确定性来源。
The Southeast Pacific (SEP) has distinct climate features that are governed by interactions among processes at multiple spatial scales and thus are hard to represent in climate models. This study investigates the local and remote impacts of various physical processes on surface fluxes over SEP in the Community Atmosphere Model version 5 by using a limited-area parameter perturbation approach. In this approach, physical parameters from the Zhang-McFarlane (ZM) convection scheme and the turbulence parameterization scheme of Cloud Layers Unified by Binormals (CLUBB) are perturbed in specific regions, but fixed outside. Three limited-area perturbed parameter ensembles are performed over SEP, the Intertropical Convergence Zone (ITCZ) and the South Pacific convergence zone (SPCZ), respectively, with the simulations over SEP the primary focus that can respond to both local impacts and remote impacts from ITCZ and SPCZ. Results show that most of the variability of surface radiative fluxes is explained by the local impacts of sub-grid physical processes and those related to shallow convection are most important. By contrast, a considerable portion of the variability of the surface latent heat flux is attributed to the remote effects from ITCZ and SPCZ, which are mainly contributed by the ZM parameters that can affect the large-scale circulation by modulating the diabatic heating related to precipitation. Both the latent heat flux and shortwave radiative flux over SEP increase with the eastern-ITCZ precipitation due to the stronger surface wind and less clouds, respectively. Overall, our results help better understand the sources of uncertainties in the simulated SEP climate.