The parameterization of the boundary layer is a challenge for regional climate models of the Arctic. In particular, the stable boundary layer (SBL) over Greenland, being the main driver for substantial katabatic winds over the slopes, is simulated differently by different regional climate models or using different parameterizations of the same model. However, verification data sets with high-resolution profiles of the katabatic wind are rare. In the present paper, detailed aircraft measurements of profiles in the katabatic wind and automatic weather station data during the experiment KABEG (Katabatic wind and boundary-layer front experiment around Greenland) in April and May 1997 are used for the verification of the regional climate model COSMO-CLM (CCLM) nested in ERA-Interim reanalyses. CCLM is used in a forecast mode for the whole Arctic with 15 km resolution and is run in the standard configuration of SBL parameterization and with modified SBL parameterization. In the modified version, turbulent kinetic energy (TKE) production and the transfer coefficients for turbulent fluxes in the SBL are reduced, leading to higher stability of the SBL. This leads to a more realistic representation of the daily temperature cycle and of the SBL structure in terms of temperature and wind profiles for the lowest 200 m.

中文翻译：

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格陵兰岛上的Katabatic边界层结构的区域气候模式模拟评估

边界层的参数化是北极地区气候模型的一个挑战。尤其是，格陵兰岛上稳定的边界层（SBL）是坡道上大量Katbatic风的主要驱动力，它通过不同的区域气候模型或使用同一模型的不同参数来模拟不同。但是，很少有带有方阵风高分辨率剖面的验证数据集。在本文中，飞机的详细测量数据是在1997年4月和5月进行的KABEG实验（格陵兰岛附近的Katabatic风和边界层前缘实验）期间，在风电场和自动气象站数据中进行测量的，用于验证区域气候模型嵌套在ERA-Interim重新分析中的COSMO-CLM（CCLM）。CCLM在整个北极地区的预报模式下使用，分辨率为15 km，并以SBL参数化和修改后的SBL参数化的标准配置运行。在改进版本中，SBL中湍动能（TKE）的产生和湍流通量的传递系数都减小了，从而提高了SBL的稳定性。这样就可以从最低200 m的温度和风廓线更真实地表示每日温度周期和SBL结构。