准格尔盆地西北缘一次寒潮天气特征分析

通过分析2011年2月下旬准格尔盆地西北缘发生的一场寒潮天气,总结了形成这次天气的环流背景、中低层温度场及冷平流垂直变化特征.结果表明,欧洲脊主体稳定,脊顶缓慢东南垮,西伯利亚槽逆转南压西伸,槽前形成强盛的西南急流,使天气前期区域气温快速上升.槽后西北风带风速不断加强,输送高纬冷空气南下堆积,冷平流快速进入中低层大气,强冷空气在近地面猛烈暴发,是形成此次寒潮天气的主要成因.

Analysis on the Weather Feature of a Cold Wave in the Northwestern Margin of Junggar Basin

By analyzing the cold wave in the northwestern margin of Junggar Basin in late February 2011,the circulation background,lower temperature field and vertical variation characteristics of cold advection were summarized.The analysis shows that high pressure ridges of Europe was stable; ridge top slowed down toward southeast; the Siberian trough rotated counter-clockwise and stretched southwestwards.It made the southwestern jets extremely strong and made the ground temperature to rise rapidly in early weather.The northwest wind constantly enhanced behind trough,transport the high latitudes cold air to move southwards and be piled up.The cold advection strengthened and accessed into middlelower layer quickly.The cold air violently broke near the ground layer.All those are the main causes of the cold wind.