DOI: 10.1029/2017JD028176
Scopus记录号: 2-s2.0-85052375278
论文题名: A Parameterization of Turbulent-Scale and Mesoscale Orographic Drag in a Global Atmospheric Model
作者: Koo M.-S. ; Choi H.-J. ; Han J.-Y.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2018
卷: 123, 期: 16 起始页码: 8400
结束页码: 8417
语种: 英语
英文摘要: The effect of drag due to subgrid orography with turbulent scales, the so-called turbulent orographic form drag, is introduced by revising the surface exchange coefficient for momentum, to alleviate the overall positive bias in wind speed in the near-surface and low-level troposphere over land. Also, the excessive flow-blocking drag, responsible for negative biases in low-level wind speed over highly complex terrains, is abated by modifying the height of the blocked layer, which is achieved without a significant deficiency of total surface drag because of additional turbulent orographic form drag. The impact of the revised subgrid-scale orography parameterization is investigated on the medium-range forecast (January and July 2016) and seasonal ensemble prediction (June–August 2013 and December 2013 to February 2014) regarding stress partitioning and skill scores. With the revised subgrid-scale orography schemes, total surface stress and its partitioning resemble those of the ERA-Interim. Meanwhile, the turbulent (mesoscale orographic) stress is enhanced (reduced) due to the additional turbulent orographic form drag (weakened flow-blocking drag). For the medium-range forecast, systematic biases in near-surface and low-level wind speed are satisfactorily rectified by adding turbulent orographic form drag (reducing flow-blocking drag) in the regions with positive biases across the land (negative biases over highly complex terrains) against reanalysis, as well as observation data. Seasonal simulation is also improved because the weak polar night jet and the corresponding warm pole biases are alleviated by the reductions of the orographic gravity wave and resolved wave drag, which are driven by the revised low-level drag. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113242
Appears in Collections: 气候减缓与适应
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作者单位: Korea Institute of Atmospheric Prediction Systems, Seoul, South Korea
Recommended Citation:
Koo M.-S.,Choi H.-J.,Han J.-Y.. A Parameterization of Turbulent-Scale and Mesoscale Orographic Drag in a Global Atmospheric Model[J]. Journal of Geophysical Research: Atmospheres,2018-01-01,123(16)