The characteristics of atmospheric boundary layer height over the Arctic Ocean during MOSAiC
The characteristics of atmospheric boundary layer height over the Arctic Ocean during MOSAiC
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DOI：
10.5194/acp-23-8683-2023
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发表时间：
2023-08
影响因子：
6.3
通讯作者：
Shijie Peng;Qinghua Yang;M. Shupe;Xingya Xi;Bo Han;Dake Chen;S. Dahlke;Changwei Liu
中科院分区：
文献类型：
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作者：
Shijie Peng;Qinghua Yang;M. Shupe;Xingya Xi;Bo Han;Dake Chen;S. Dahlke;Changwei Liu
抽象的。大气边界层（ABL）在北极中部气候系统中的重要作用已得到公认，但大气边界层高度（ABLH）（定义为邻近地面的连续湍流层）却很少被研究。利用北极气候研究多学科漂流观测站（MOSAiC）考察期间的一年四季探空数据，改进了一种考虑云效应的基于Richardson数的算法，并分析了北冰洋上空ABLH的特征和变化。结果表明，年周期的明显特征是在5月有一个明显的峰值，在1月和7月有两个各自的极小值。ABLH的年变化主要受ABL热结构演化的控制。在冬季和夏季的温度逆温加强季节性辐射冷却和暖空气平流与地面温度的限制融化，分别导致在这些时候的低ABLH。气象和湍流变量也发挥了重要作用，在ABLH的变化，包括近地面位温梯度，摩擦速度，和湍流动能（TKE）耗散率。此外，MOSAiC ABLH比ABLH在夏季的北冰洋（SHEBA）的表面热收支实验期间，这表明有在北极ABL结构在夏季融化季节的大的变化受到抑制。
Abstract. The important roles that the atmospheric boundary layer (ABL) plays in the central Arctic climate system have been recognized, but the atmospheric boundary layer height (ABLH), defined as the layer of continuous turbulence adjacent to the surface, has rarely been investigated. Using a year-round radiosonde dataset during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition, we improve a Richardson-number-based algorithm that takes cloud effects into consideration and subsequently analyze the characteristics and variability of the ABLH over the Arctic Ocean. The results reveal that the annual cycle is clearly characterized by a distinct peak in May and two respective minima in January and July. This annual variation in the ABLH is primarily controlled by the evolution of the ABL thermal structure. Temperature inversions in the winter and summer are intensified by seasonal radiative cooling and warm-air advection with the surface temperature constrained by melting, respectively, leading to the low ABLH at these times. Meteorological and turbulence variables also play a significant role in ABLH variation, including the near-surface potential temperature gradient, friction velocity, and turbulent kinetic energy (TKE) dissipation rate. In addition, the MOSAiC ABLH is more suppressed than the ABLH during the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment in the summer, which indicates that there is large variability in the Arctic ABL structure during the summer melting season.