The present study describes the atmospheric component of the sixth‐generation climate models of the Centre National de Recherches Météorologiques (CNRM), namely, ARPEGE‐Climat 6.3. It builds up on more than a decade of model development and tuning efforts, which led to major updates of its moist physics. The vertical resolution has also been significantly increased, both in the boundary layer and in the stratosphere. ARPEGE‐Climat 6.3 is now coupled to the new version (8.0) of the SURFace EXternalisée (SURFEX) surface model, in which several new features (e.g., floodplains, aquifers, and snow processes) improve the water cycle realism. The model calibration is discussed in depth. An amip‐type experiment, in which the sea surface temperatures and sea ice concentrations are prescribed, and following the CMIP6 protocol, is extensively evaluated, in terms of climate mean state and variability. ARPEGE‐Climat 6.3 is shown to improve over its previous version (5.1) by many climate features. Major improvements include the top‐of‐atmosphere and surface energy budgets in their various components (shortwave and longwave, total and clear sky), cloud cover, near‐surface temperature, precipitation climatology and daily‐mean distribution, and water discharges at the outlet of major rivers. In contrast, clouds over subtropical stratocumulus decks, several dynamical variables (sea level pressure, 500‐hPa geopotential height), are still significantly biased. The tropical intraseasonal variability and diurnal cycle of precipitation, though improved, remained area of concerns for further model improvement. New biases also emerge, such as a lack of precipitation over several tropical continental areas. Within the CMIP6 context, ARPEGE‐Climat 6.3 is the atmospheric component of CNRM‐CM6‐1 and CNRM‐ESM2‐1.

中文翻译：

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CNRM全球大气模型ARPEGE-Climat 6.3：说明和评估

本研究描述了国家气象中心（CNRM）第六代气候模式的大气成分，即ARPEGE-Climat 6.3。它建立在十多年来模型开发和调整工作的基础上，这导致了其潮湿物理学的重大更新。在边界层和平流层中，垂直分辨率也得到了显着提高。ARPEGE-Climat 6.3现在已与SURFaceEXternalisée（SURFEX）表面模型的新版本（8.0）耦合，该模型具有多个新功能（例如洪泛区，含水层和降雪过程）改善了水循环的真实性。深入讨论模型校准。一个AMIP根据气候平均状态和变异性，广泛评估了这种类型的实验，其中规定了海面温度和海冰浓度并遵循CMIP6协议。显示ARPEGE-Climat 6.3在许多气候特征方面均比其先前版本（5.1）有所改进。重大改进包括各个组成部分（短波和长波，总和晴朗的天空）的大气层顶部和地表能量预算，云量，近地表温度，降水气候和日均分布以及出口处的排水主要河流。相比之下，亚热带平流积层甲板上的云，几个动力学变量（海平面压力，500-hPa地势高度）仍然存在明显偏差。热带季节内变化和降水的昼夜周期虽然有所改善，仍然是需要进一步改进模型的领域。还出现了新的偏见，例如几个热带大陆地区缺乏降水。在CMIP6背景下，ARPEGE-Climat 6.3是CNRM-CM6-1和CNRM-ESM2-1的大气成分。