Atmospheric Moisture and Cloud Cover Characteristics Forecast by AMPS
Atmospheric Moisture and Cloud Cover Characteristics Forecast by AMPS
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AMPS 的大气湿度和云量特征预测
DOI：
10.1175/2008waf2006100.1
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发表时间：
2008
影响因子：
2.9
通讯作者：
D. Bromwich
中科院分区：
文献类型：
--
作者：
R. Fogt;D. Bromwich
本文将南极中尺度预报系统（AMPS）对大气湿度和云量（CF）的预报与南极麦克默多站和阿蒙森-斯科特南极站（以下简称南极站）的观测资料进行了比较。总体而言，它被发现，该模型产生过多的水分在这两个网站在对流层中上部，因为一个较弱的垂直下降的水分在AMPS比观察到的。与观测结果的相关性表明，AMPS在捕获麦克默多低层湿度变率和南极站高层湿度变率方面做得很好。模型低估了两个地点的云量，但是，对AMPS经验CF算法的修改消除了这种负偏差，将云冰路径的权重增加了一倍以上。根据AMPS内云冰和云液态水的微物理量，对一种“伪卫星”产品进行了初步评估，并与国防气象卫星计划（DMSP）进行了比较。图像在夏季检查云的变化在AMPS的更广泛的性能。这些比较表明，该模式预测高层次的云覆盖和运动的保真度，这解释了修改后的CF算法和观测到的CF之间的良好协议。然而，该产品也证明了在捕获冷冰表面上的低层云量方面的不足，这主要与微物理方案产生的过冷液态水不足有关，这也降低了CF与观测的相关性。结果表明，AMPS预测的整体CF量和高云变率显着，使其成为一个可靠的工具，这些领域在南极洲的长期气候研究。
Antarctic Mesoscale Prediction System (AMPS) forecasts of atmospheric moisture and cloud fraction (CF) are compared with observations at McMurdo and Amundsen–Scott South Pole station (hereafter, South Pole station) in Antarctica. Overall, it is found that the model produces excessive moisture at both sites in the mid- to upper troposphere because of a weaker vertical decrease of moisture in AMPS than observed. Correlations with observations suggest AMPS does a reasonable job of capturing the low-level moisture variability at McMurdo and the upper-level moisture variability at South Pole station. The model underpredicts the cloud cover at both locations, but changes to the AMPS empirical CF algorithm remove this negative bias by more than doubling the weight given to the cloud ice path. A “pseudosatellite” product based on the microphysical quantities of cloud ice and cloud liquid water within AMPS is preliminarily evaluated against Defense Meteorological Satellite Program (DMSP) imagery during summer to examine the broader performance of cloud variability in AMPS. These comparisons reveal that the model predicts high-level cloud cover and movement with fidelity, which explains the good agreement between the modified CF algorithm and the observed CF. However, this product also demonstrates deficiencies in capturing low-level cloudiness over cold ice surfaces primarily related to insufficient supercooled liquid water produced by the microphysics scheme, which also reduces the CF correlation with observations. The results suggest that AMPS predicts the overall CF amount and high cloud variability notably well, making it a reliable tool for longer-term climate studies of these fields in Antarctica.