Polar lows, its structure and mechanism of cyclogenesis.

极地低气压、其结构和气旋发生机制。

• 批准号: 06640556
• 负责人: TSUBOKI Kazuhisa
• 金额: $ 1.28万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640556/
• 关键词: polar low; mesoscale low; cold vortex; Hokkaido polar low; convergence line; CAPS II; numerieal modeling; band cloud; 小低気圧; メソスケール; 数値モデル; CASP II; コールドロウ

A polar low over the Labrador Sea was observed on 14-15 February 1992. Satellite images obtained from the AVHRR showed the cyclogenesis and development of the polar low. The cloud streaks over the Labrador sea suggested that a convergence formed between the westerly from Eastern Canada and the northeasterly from Greenland before when the polar low developed. A vortex formed along the convergence zone and developed into the polar low of which the horizontal diameter was about 500 km.On the basis of the JMA global objective analysis (GANAL), an intense upper cold vortex was located over the Labrador sea when the polar low occurred. The GANAL data showed a dry and cold westerly was prevailing over the Labrador sea and that the convergence occurred between the westerly from Eastern Canada and the northeasterly from Greenland. The polar low formed along the convergence zone. The polar low was shallow disturbance which was confined to below 700 hPa.In order to clarify the detailed structure and the processes of cyclogenesis and development of the polar low, we made numerical simulation experiments using the Japan Spectral Model. JSM simulated well the development of the Labrador polar low. First, a convergence occurred between the westerly from Eastern Canada and the northeasterly from Greenland. Then, the polar low developed along the convergence zone. There was a strong stable layer above 700 hPa and the disturbance of the polar low was confined to below 700 hPa.As far as this case of the Labrador polar low, we could infer that the convergence was important for the cyclogenesis and that the latent and sensible heat fluxes were important for the development. It is not clear presently the role of the upper cold vortex in the cyclogenesis of the polar low.

1992年2月14日至15日，在拉布拉多海上空观测到极地低压。从AVHRR获得的卫星图像显示了极地低压的气旋发生和发展。拉布拉多海上空的云纹表明，在极地低压发展之前，来自加拿大东部的西风和来自格陵兰的东北风之间形成了一种辐合。极地低压发生时，沿辐合带形成的涡旋发展成水平直径约500公里的极地低压。根据JMA全球客观分析(GANAL)，极地低压发生时，拉布拉多海上空有一强冷涡。Ganal的数据显示，拉布拉多海普遍存在干燥而寒冷的西风，来自加拿大东部的西风和来自格陵兰的东北风之间发生了辐合。极地低压沿辐合带形成。极地低压为浅层扰动，限于700hPa以下。为了阐明极地低压的详细结构和气旋发生发展过程，我们利用日本谱模式进行了数值模拟试验。JSM模式较好地模拟了拉布拉多极地低压的发展。首先，来自加拿大东部的西风和来自格陵兰岛的东北风之间发生了辐合。然后，极地低压沿着辐合带发展。在700hPa以上有一个较强的稳定层，极地低压的扰动局限在700hpa以下。对于拉布拉多极地低压的这种情况，我们可以推断，辐合对气旋的发生是重要的，潜热和感热通量对气旋的发展是重要的。目前尚不清楚高空冷涡在极地低压气旋发生中的作用。

项目成果

Kazuhisa Tsuboki and Gorow Wakahama: "Mesoscale cyclogenesis in winter monsoon air streams : Quasi-geostrophic baroclinic instability as a mechanism of the cyclogenesis off the west coast of Hokkaido Island, Japan." J.Meteor.Soc.Japan. 70. 77-93 (1992)

Kazuhisa Tsuboki 和 Gorow Wakahama：“冬季季风气流中的中尺度气旋发生：准地转斜压不稳定性是日本北海道岛西海岸气旋发生的机制。”

Y.Fujiyoshi, Y.Kodama, K.Tsuboki, K.Nishimura and N.Ono: "Structures of cold air during the development of a broad band cloud and a meso-beta-scale vortex : Simultaneous two-point radiosonde observations." J.Meteor.Soc.Japan. 74. 281-297 (1996)

Y.Fujiyoshi、Y.Kodama、K.Tsuboki、K.Nishimura 和 N.Ono：“宽带云和中观 β 尺度涡旋发展过程中的冷空气结构：同时两点无线电探空仪观测。”

坪木和久: "冬季日本海上に発生するメソスケール低気圧の数値実験" 月刊海洋. 5. 125-133 (1993)

Kazuhisa Tsuboki：“冬季日本海上空发生的中尺度气旋的数值实验”月刊Kaiyo。5. 125-133（1993）

Yoshimitsu Ogura, Kazuhisa Tsuboki, Hisao Ohno, Kenichi Kusunoki and Hiroshi Nirasawa: "A Case Study of the Formation of an Embedded-Areal-Type Cloud Band over Kanto Plain." J.Meteor.Soc.Japan. 73. 857-872 (1995)

Yoshimitsu Ogura、Kazuhisa Tsuboki、Hisao Ohno、Kenichi Kusunoki 和 Hiroshi Nirasawa：“关东平原嵌入式区域型云带形成的案例研究”。

坪木和久: "温帯低気圧に伴う波状の降水エコー(Wave-like Bands Associated with Extratropical cyclone)." 天気. 42(color page). (1995)

Kazuhisa Tsuboki：“与温带气旋相关的波状带。”（彩页）。