| 锋面滑升运动的物理机制 |
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| 引用本文： | 王文儒,白山.锋面滑升运动的物理机制[J].气象,2010,36(9):42-46. |
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| 作者姓名： | 王文儒 白山 |
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| 作者单位： | 辽宁省辽阳市气象局,辽阳,111000 |
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| 摘 要： | 锋面滑升运动是形成锋面降水的重要原因,弄清锋面滑升运动的物理机制对锋面降水的预报是必要的。依据大气动力学原理,对锋面滑升运动的物理成因进行了研究。已知暖空气沿锋面的滑动与暖空气垂直于锋面的风速(u_w)和锋面移动速度(c)之差有关。当暖空气垂直于锋面的风速小于锋面的移动速度(u_wc)时,暖空气向上滑动;当暖空气垂直于锋面的风速大于锋面的移动速度(u_wc)时,暖空气向下滑动。因为锋面的移动速度小于锋后冷空气垂直于锋面的风速(cu_c),所以,暖空气沿锋面的滑动与锋区中垂直于锋面方向的风速的分布有关,当锋区中有(?)u/(?)u0时,暖空气必定向下滑动;暖空气若向上滑动,锋区中必为(?)u/(?)x0。本文依据大气动力学原理给出了锋面坡度公式,通过演绎该式,得到了分析锋区中(?)u/(?)x的公式,结果表明:(1)当锋面坡度增大时,大气沿锋面向上滑动,反之向下滑动。(2)锋面强度加强时,大气沿锋面向上滑动,反之向下滑动。(3)暖平流时上滑,冷平流时下滑。(4)当锋面上出现气旋式涡度增大时,大气沿锋面向上滑动,反之向下滑动。(5)当垂直于锋面方向的地转风沿锋面由下向上增大时,大气沿锋面向上滑动,反之向下滑动。
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| 关 键 词： | 锋面 滑升运动 滑动成因 |
| 收稿时间： | 2009/9/16 0:00:00 |
| 修稿时间： | 4/8/2010 12:00:00 AM |
Physical Mechanism of Gliding Motion on the Frontal Surface |
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| WANG,Wenru and BAI,Shan.Physical Mechanism of Gliding Motion on the Frontal Surface[J].Meteorological Monthly,2010,36(9):42-46. |
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| Authors: | WANG Wenru and BAI Shan |
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| Institution: | Liaoyang Meteorological Office of Liaoning Province, Liaoyang 111000;Liaoyang Meteorological Office of Liaoning Province, Liaoyang 111000 |
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| Abstract: | Air upglide motion on the frontal surface is the important cause for the frontal precipitation. That the mechanism of air upglide motion and downglide motion on the frontal surface is understood is necessary to forecast frontal precipitation. Based on the dynamics of atmosphere, the cause for air upglide motion and downglide motion on the frontal surface was studied. The glide motion of warm air on the frontal surface is related to the difference between the wind speed of warm air in the direction perpendicular to the frontal surface and the moving speed of the frontal surface. Warm air upglide occurs when the wind speed of warm air in the direction perpendicular to the frontal surface is less than the moving speed of frontal surface (uwc). Because the moving speed of frontal surface is less than the wind speed of cold air in the direction perpendicular to the frontal surface (c0 in the frontal zone; however,
u/x<0 in the frontal zone is the necessary condition of upglide motion of warm air. Based on the dynamics of atmosphere, this article shows the formula of the frontal slope. Deduction of this formula works out the formula for analyzing u/x. The following conclusions can be drawn. First, air is upglide motion on the frontal surface when the frontal slope increases, on the contrary, downglide. Second, air is upglide motion when frontal intensity increases, on the contrary, downglide. Third, air is upglide motion when it flows from warm to cold; air is downglide motion when it flows from cold to warm. Fourth, air is upglide motion when the cyclonic vorticity develops on the frontal surface,on the contrary,downglide. Fifth, air is upglide motion when the speed of geostrophic wind in the direction perpendicular to the frontal surface is rising from lower to upper frontal surface,on the cotrary,air is downglide motion. |
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| Keywords: | frontal surface gliding motion causes of gliding |
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