Study on the Formation of Cold Air Damming and Its Synoptic Impacts
-
摘要: 冷空气堆积（cold air damming，CAD）是低层冷空气受地形阻挡产生的一种中尺度天气现象，北半球通常发生在山脉的东侧，造成云量增加、温度降低以及降水类型和降水落区的改变。CAD全年都会发生，冷季常造成冻雨天气，暖季往往会触发雷暴、大风、冰雹等强对流天气。在地形作用下地转适应关系的重新调整是CAD形成的动力基础，但冷平流、绝热冷却和非绝热冷却等热力因子对CAD的形成和发展也至关重要。尽管中尺度数值模式显著提高了CAD事件的预测能力，但这些模式仍有低估CAD影响和持续时间的倾向，即便是快速更新的高分辨率中尺度模式也会低估太阳遮蔽的影响，因此，CAD的预测对研究和预报人员来说一直是个棘手的世界性难题。主要从时空分布、天气影响、形成机理和预报预测等方面对其研究历程进行了回顾。Abstract: Cold air damming (CAD) is a mesoscale weather phenomenon caused by low-level cold air blocked by terrain. In the Northern Hemisphere, CAD usually occurs on the eastern side of mountains, resulting in increased cloud cover, decrease in temperature, and changes in precipitation types and distribution. CAD develops throughout the year, and often causes freezing rain in cold season, and severe convective weather such as thunderstorm, wind and hail in warm seasons. The reshaping of geostrophic adjustment under the terrain effect is the dynamic basics of CAD formation, but the thermal factors such as cold advection, adiabatic and non-adiabatic cooling are also crucial to the formation and development of CAD. Although mesoscale numerical models have significantly improved the predictability of CAD events, these models still tend to underestimate their impacts and duration. Even the rapidly updated high-resolution mesoscale models still undervalue the effects of solar shading. Therefore, CAD prediction has always been a difficult worldwide problem for researchers and forecasters. This paper mainly reviews the CAD research history from spatial-temporal distribution, synoptic impacts, formation mechanism and prediction. There is an absence of research on the most significant CAD on the eastern Tibetan Plateau.
-
计量
- 文章访问数: 1
- HTML全文浏览量: 0
- PDF下载量: 1
下载:
