Synoptic situations causing high precipitation rates on the Antarctic plateau: observations from Kohnen Station, Dronning Maud Land
Synoptic situations causing high precipitation rates on the Antarctic plateau: observations from Kohnen Station, Dronning Maud Land
复制标题
导致南极高原高降水率的天气状况：来自 Dronning Maud Land Kohnen 站的观测
作者：
G. Birnbaum;Ralf Brauner;H. Ries
Kohnen站（75°S，0°E，2892 m）是欧洲南极洲冰岩芯钻探项目的两个钻探点之一。雪福尔斯在Kohnen一年只有几次，相对较高的降水率为1毫米至超过5毫米的水当量每事件。这些事件对年累积总量的贡献很大，其长期平均值为每年62毫米水当量。对于冰芯解释，重要的是要了解天气过程导致如此高的降水率。我们的调查是基于视觉观察期间的大雪在Kohnen自2001/2002年夏季运动。相应的天气形势可分为三类。第一类是向东移动的低压系统的阻塞锋到达高原的地方，这是相当频繁的发生。第二类是在格林威治子午线以东形成的低压或次级低压向西移动（逆行运动），锋面云影响高原。在III级中，大规模的抬升过程（由于Kohnen站以西的高空低气压）导致德龙宁毛德地高原上空形成云层。
Kohnen Station (75°S, 0°E, 2892 m) is one of the two drilling sites of the European Project for Ice Coring in Antarctica. Snow falls at Kohnen only a few times a year with comparatively high precipitation rates of 1 mm to over 5 mm water equivalent per event. These events contribute considerably to the total annual accumulation of which the long-term mean value is 62 mm water equivalent per year. For ice core interpretation, it is important to understand synoptic processes leading to such high precipitation rates. Our investigation is based on visually observed periods of heavy snowfall at Kohnen during summer campaigns since 2001/2002. The corresponding synoptic situations can be grouped into three categories. Category I is where occluding fronts of eastward-moving low pressure systems reach the plateau, a fairly frequent occurrence. Category II is where lows or secondary lows formed east of the Greenwich Meridian move to the west (retrograde movement), and frontal clouds influence the plateau. In Category III, large-scale lifting processes (due to an upper air low west of Kohnen Station) lead to cloud formation over the plateau of Dronning Maud Land.