2003年12月19日日本海极地低压个例的观测研究

An Observational Study of a Polar Low over the Japan Sea on December 19, 2003

为进一步认识冬季灾害性天气 ,利用尽可能多的观测资料对 2 0 0 3 12 19～ 2 0日在日本海北部发生的 1个中α尺度的极地低压进行了研究 ,并对其时空结构进行了详细分析。该极地低压于 19日 11UTC在 1个天气尺度的低压后部形成 ,2 0日 0 8UTC消亡在日本以东洋面上 ,持续时间约为 2 0h以上 ,卫星云图显示其成熟阶段出现了罕见的“双眼壁”结构。利用高分辨率的NCEP (NationalCentersforEnvironmentalPrediction)的FNL(FinalAnalyses)资料的分析发现 ,来自欧亚大陆的冷空气侵入到日本海上空相对暖的空气中并相互扭缠在一起 ,为极地低压的发展提供了有利的条件 ,在成熟阶段极地低压中心出现了“暖心”结构。

The structure and evolutionary process of a meso-α-scale polar low occurred over the Japan Sea on December 19 2003 were investigated by using almost all available observational data, including the GOES(Geostationary Operational Environmental Satellite)-9, NOAA(National Oceanic and Atmospheric Administration)-17 satellite imagery, the FNL(Final Analyses) data issued by the NCEP(National Centers for Environmental Prediction), the surface observational data for the Japan Islands, and the sounding data at Akita station. The polar low initiated over the northwestern part of the Japan Sea within a synoptic-scale parent low, and disappeared over the east of the Japan Islands with a lifetime of about 20-h. It is of interest that two concentric “eye” walls associated with this polar low were found in satellite images at its most mature stage. Also, a “warm core' structure of this polar low was found. The intertwinement of the cold air from the Asian continent and the warm air over the ocean with each other provided a favorable condition for the development of this polar low.