| 摘要: |
| 为了分析不同天气尺度系统风下的海风发生发展过程, 以及天气尺度系统风向对海风的影响,利用ARPS 中尺度数值模式, 对2006 年青岛国际帆船赛期间的3 次较强的海风过程进行了数值模拟研究, 结果发现, 无论在何种天气系统背景场下, 当沿海海陆温差达1～2℃时, 海风就可以发生。当近地层天气尺度系统风为离岸风时, 海风向内陆地区推进距离较近。否则, 海风可以向内陆推进很远。当近地层天气尺度系统风场较弱时, 热力作用对海风的发生发展起主要作用, 但海风开始和结束过程均较慢; 当近地层天气尺度系统风场为较强的离岸风时, 动力和热力作用对于海风的发生发展均起作用。海风开始时, 首先在近地层较浅的范围内。与海风有关的垂直环流圈一般在下午—傍晚出现, 并且位于约600～900 m 高度处, 强度较弱。傍晚到午夜, 海风垂直环流的强度反而进一步发展, 形成为清晰的闭合环流圈, 高度约在300～600 m 处, 伴有明显的暖心结构。午夜后, 随着地面的进一步降温,海风环流崩溃。当近地层天气尺度系统风较弱时, 海风的垂直环流圈维持时间长; 当近地层天气尺度系统风为较强的离岸风时, 海风的垂直环流圈维持时间短。 |
| 关键词: 天气尺度系统风 海风 数值模拟 |
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| 基金项目:国家自然科学基金项目(40705017); 山东省自然科学基金项目(Q2007E03); 中国气象局新技术推广项目(CMATG2007M34); 山东省气象局重点项目(2006sdqxz08, 2009sdqxz01) |
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| Comparative analysis of the development of the sea breezes under different synoptic-scale winds |
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| Abstract: |
| In order to analyze the development of the sea breezes under different synoptic-scale wind, using the ARPS(The Advanced Regional Prediction System)model, three sea breeze cases during the 2006 Qingdao International Regatta were simulated. Results show that the sea breezes can occur if the land-sea temperature difference is over 1～2℃ under whatever synoptic-scale wind. When the synoptic-scale wind in the boundary is offshore the sea breeze cannot push in land too far; otherwise, the sea breeze can push in land for a long distance. When the synoptic-scale wind is weak, thermal effect is critical for the occurrence of the sea breeze. When it is strong offshore, dynamic and thermal effects are both important for the occurrence of the sea breeze. The sea breeze is very shallow at the beginning. The vertical circulation of the sea breezes usually starts in the late afternoon to the evening and the height of it is 600～900 m or so. From evening to mid-night the vertical circulation of the sea breeze develops instead and clear close circulation with warm core can be found. The height of the close circulation is low to be around 300 m. After mid-night the sea breeze circulation dies. When the synoptic-scale wind in the boundary is weak the vertical circulation of the sea breeze tends to maintain for a long time; in comparison, when the synoptic-scale wind is stronger offshore the vertical circulation of the sea breeze can keep shorter. |
| Key words: synoptic-scale wind, sea breeze, numerical simulation |
