| 大连机场典型低空风切变的成因分析 |
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| 引用本文：翁雪玲，于佳松,徐建文..大连机场典型低空风切变的成因分析[J].气象与环境科学,2020,43(1):81-89.Weng Xueling,Yu Jiasong,Xu Jianwen..Cause Analysis of Typical Low-level Wind Shear in Dalian Airport[J].Meteorological and Environmental Sciences,2020,43(1):81-89. |
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| DOI：doi:10.16765/j.cnki.1673-7148.2019.04.011 |
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| 中文摘要:风切变是指空间两点之间的风的矢量差，风切变分为水平风切变和垂直风切变。航空气象学中，低空风切变通常是指近地面600 m高度以下的垂直风切变，低空风切变严重危害航空活动安全，尤其是在飞机起飞和着陆阶段。为了提高对低空风切变的预报准确率和提前预警时间，利用大连机场话音方式航空器报告统计大连机场出现的低空风切变特点。大连机场低空风切变出现最多的季节是秋末和春季，其中以西北大风和偏北大风造成的低空风切变最为典型，这种切变常常出现在地面风向为360°或350°、平均风速9 m·s-1、阵风风速16 m·s-1的观测时次附近。选取3个大连机场典型低空风切变的天气个例，利用NCEP/NCAR FNL1°×1°资料分析大连机场出现典型低空风切变时的天气形势特点，利用WRF模式输出资料，分析了大连机场出现典型低空风切变时低层的风场特征。分析结果表明，WRF模式输出的风场变化较小，不能体现低空风切变的突变特征，利用模式输出资料计算得到的反映偏差风相对大小的I值与风切变的出现有明显关系，当I大于0.5且逐渐增加时，容易出现低空风切变，当I小于0.5且逐渐减小时，不易出现低空风切变，可以利用I值及其变化情况进行风切变的预报预警。 |
| 中文关键词:低空风切变 风 气压梯度 偏差风 |
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| Cause Analysis of Typical Low-level Wind Shear in Dalian Airport |
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| Abstract:Wind shear refers to the vector difference of wind between two points in space. Wind shear is divided into horizontal wind shear and vertical wind shear. In aviation meteorology, low level wind shear usually refers to vertical wind shear below 600 m above the surface. Low level wind shear seriously endangers the safety of aviation activities, especially during the take off and landing stages of aircraft. In order to improve the forecast accuracy and early warning time of low level wind shear, the characteristics of low level wind shear in Dalian airport are summed up by using the Dalian Airport discourse mode reports. The most frequent seasons of low level wind shear at Dalian Airport are late autumn and spring, when the low level wind shear caused by strong northwest and north winds is the most typical wind shear. Such shear often occurs near the observation time, accompanied by surface wind with 9 m·s-1 average wind speed or 16 m·s-1 gust speed in 360° or 350° direction. In this paper, three examples of typical low level wind shear weather in Dalian airport are selected, and the characteristics of typical low level wind shear weather at Dalian airport are analyzed based on the NCEP/NCAR FNL 1°×1°data. Besides, the WRF model output data are used and the characteristics of the wind field at the bottom of the typical low level wind shear in Dalian Airport are analyzed. The analysis results denote that the wind field changes of the WRF model output are small and cannot reflect the mutation characteristics of low level wind shear. The calculation of the I value reflecting the deviation wind, calculated by using the model output data has a significant correlation with the occurrence of wind shear. When I is greater than 0.5 and gradually increases, low level wind shear is prone to occur; when I is less than 0.5 and gradually decreases, low level wind shear is not easy to occur. Therefore, the I value and its changes can be used in the forecasting and early warning of low level wind shear events. |
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