| 大涡模式分辨率对海洋信风区大气边界层结构和演变模拟的影响 |
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| 引用本文： | 任燕,黄倩,张君霞,王婵.大涡模式分辨率对海洋信风区大气边界层结构和演变模拟的影响[J].热带气象学报,2018,34(1):23-33. |
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| 作者姓名： | 任燕 黄倩 张君霞 王婵 |
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| 作者单位： | 1.北京大学物理学院大气与海洋科学系，北京 100871 |
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| 基金项目： | 国家自然科学基金项目41775013国家自然科学基金项目41275006国家自然科学基金项目41205007 |
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| 摘 要： | 利用BOMEX（巴巴多斯海洋与气象学试验）的探空资料和LEM（大涡模式），通过改变LEM水平分辨率的敏感性数值试验，对比分析不同尺度的湍涡对信风积云边界层中混合层和云层的结构、演变以及对流形式和强度的影响。结果表明，水平分辨率较高时模拟的湍涡尺度较小、混合层顶的夹卷作用较强，模拟的混合层较暖、较干，而且模拟的对流泡尺度较小、强度较大，能够模拟出较精细的边界层结构；而水平分辨率较低时则相反。模拟的湍涡尺度对海洋信风区边界层积云中液态水混合比的模拟结果影响较大:LEM模拟的湍涡尺度较小时模拟的信风积云形成的时间较早、云顶高度较高，单个云块的体积较小但数目较多，液态水含量较高；而模拟的湍涡尺度较大时则相反。虽然水平分辨率为50 m和125 m的试验都能模拟出较精细的信风边界层中混合层、云层的结构和演变特征，但是，考虑到提高分辨率在模拟过程中产生的噪音信号对结果的影响以及计算时间等问题，LEM采用125 m的水平网格距是对海洋信风边界层积云对流模拟较为理想的选择。
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| 关 键 词： | 大气物理学 边界层结构 大涡模式 信风积云 模式分辨率 |
| 收稿时间： | 2016-10-28 |
EFFECT OF LARGE EDDY RESOLUTION ON SIMULATION OF STRUCTURE AND EVOLUTION OF THE MARINE TRADE-WIND BOUNDARY LAYER |
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| Institution: | 1.Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China2.Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China3.Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China |
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| Abstract: | The effects of turbulent eddies with various scales on the structure and evolution of mixed layer and cumulus layer are analyzed by using the sounding data from the Barbados Oceanographic and Meteorological Experiment (BOMEX) and a large eddy simulation (LEM) sensitivity test with different horizontal grid spacings. The results showed that a fine structure of the boundary layer convection with a warm and dry mixed layer is simulated with smaller model horizontal grid spacings. Strong convection and entrainment also were modeled using high-resolution tests due to small turbulent eddies being resolved. If larger model horizontal grid spacings were used, larger turbulent eddies led to a weaker boundary layer convection with cooler and wetter mixed layer and weaker entrainment. The simulated scale of turbulent eddies were also shown to affect the simulation of liquid water mixing ratio in the trade-wind cumulus layer. If small turbulent eddies were modeled, this led to an early formation of trade-wind cumulus and a high cloud top. Large liquid water content with small volume of single cloud was found in the trade-wind cumulus layer. It gave the opposite results if large turbulent eddies were simulated. Considering the effects of noise signals generated by the high resolution simulations and computing time, the use of 100 m grid spacing as LEM horizontal resolution in simulating marine trade-wind cumulus boundary layer is a ideal choice, although the characteristics of mixed layer and cumulus layer from a fine trade-wind boundary layer could be modeled by using the simulation with 50 m or 100 m grid spacings. |
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