This study presents different characteristics of precipitation and synoptic-scale circulation associated with extreme precipitation events in inland and coastal Antarctica. The focus is on two stations, inland Vostok and coastal Casey. We use observed daily precipitation data from years 2004–2017 to investigate and compare the statistics on precipitation at both stations. The key areas for synoptic features favouring extreme precipitation are identified on the basis of air-mass backward trajectories, computed applying the Lagrangian HYSPLIT model. The air moisture accounting for high-precipitation events originates from the ocean but in many (some) cases the trajectories cover long distances over the ice sheet before reaching Vostok (Casey). Multiple statistical methods including composite analysis, empirical orthogonal functions (EOF), and self-organizing maps (SOMs) are used to examine the full view of synoptic patterns. At Vostok in the inland high plateau, ERA-Interim reanalysis shows that the synoptic patterns governing the extreme precipitation events are relatively complicated. Amplified planetary waves allow water vapour to reach the Vostok Station from different source regions, including the Weddell Sea, Ross Sea, and the Indian Ocean off the Amery Ice Shelf. A dipole structure of negative height anomalies to the west and positive ones to the east of the station is identified as the cause of southward water vapour transport and resulting precipitation at Casey in coastal Antarctica.

中文翻译：

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南极洲内陆和沿海站点极端降水特征比较

本研究展示了与南极洲内陆和沿海极端降水事件相关的降水和天气尺度环流的不同特征。重点是两个站点，内陆 Vostok 和沿海 Casey。我们使用 2004-2017 年观测到的每日降水数据来调查和比较两个站点的降水统计数据。根据气团后向轨迹确定有利于极端降水的天气特征的关键区域，并使用拉格朗日 HYSPLIT 模型进行计算。造成高降水事件的空气水分来自海洋，但在许多（某些）情况下，轨迹在到达 Vostok（凯西）之前跨越冰盖的很长距离。多种统计方法，包括复合分析、经验正交函数 (EOF)、和自组织地图 (SOM) 用于检查天气模式的全貌。在内陆高原的沃斯托克，ERA-Interim再分析表明，控制极端降水事件的天气模式相对复杂。放大的行星波允许水蒸气从不同的来源区域到达东方站，包括威德尔海、罗斯海和埃默里冰架附近的印度洋。气象站西面负高度异常和东面正高度异常的偶极子结构被确定为南极洲沿海凯西的水汽向南输送和由此产生的降水的原因。ERA-Interim 再分析表明，控制极端降水事件的天气模式相对复杂。放大的行星波允许水蒸气从不同的来源区域到达东方站，包括威德尔海、罗斯海和埃默里冰架附近的印度洋。气象站西面负高度异常和东面正高度异常的偶极子结构被确定为南极洲沿海凯西的水汽向南输送和由此产生的降水的原因。ERA-Interim 再分析表明，控制极端降水事件的天气模式相对复杂。放大的行星波允许水蒸气从不同的来源区域到达东方站，包括威德尔海、罗斯海和埃默里冰架附近的印度洋。气象站西面负高度异常和东面正高度异常的偶极子结构被确定为南极洲沿海凯西的水汽向南输送和由此产生的降水的原因。