This study systematically evaluates the warm sea surface temperature (SST) bias in the Subtropical Eastern North Pacific, a problem plaguing most Coupled Model Intercomparison Project Phase 6 models, using the Energy Exascale Earth System Model version 1 (E3SM). In the model at its standard resolution (1° atmosphere, 30–60 km ocean), the SST bias, exceeding several degrees, is mainly concentrated along the coast between 25°N and 40°N. In the high-resolution (0.25° atmosphere, 18–6 km ocean) version of the model, the nearshore SST bias improves considerably with a better representation of coastal upwelling. However, the offshore SST bias, approximately centered at 125°W and 25°N, is relatively stronger in the high-resolution version. To better understand the offshore warm bias in the model, a mixed-layer heat budget analysis is performed. While errors in surface radiative fluxes occur at both resolutions, positive biases in horizontal heat advection also play a role in the SST bias at high-resolution. Analysis of HighResMIP models indicates that the shift in the location of the prominent SST bias from nearshore to offshore with an increase in model spatial resolution, is not native to E3SM alone.

中文翻译：

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地球系统模型中的亚热带东部北太平洋海温偏差

这项研究使用能源百亿亿级地球系统模型版本 1 (E3SM) 系统地评估了亚热带东部北太平洋的暖海表面温度 (SST) 偏差，这是困扰大多数耦合模型比对项目第 6 阶段模型的问题。在标准分辨率（1°大气，30-60 km海洋）的模型中，超过几度的SST偏差主要集中在25°N和40°N之间的海岸。在模型的高分辨率（0.25°大气，18-6 公里海洋）版本中，近岸海温偏差显着改善，更好地代表了沿海上升流。然而，近海 SST 偏差，大约集中在 125°W 和 25°N，在高分辨率版本中相对更强。为了更好地理解模型中的海上暖偏差，进行了混合层热预算分析。虽然在两种分辨率下都会出现表面辐射通量的误差，但水平热平流的正偏差也在高分辨率的 SST 偏差中起作用。HighResMIP 模型的分析表明，随着模型空间分辨率的增加，显着 SST 偏差的位置从近岸到近海的转变并不是 E3SM 独有的。