青森県津軽平野で行われた冬季季節風とヤマセの高層気象観測, および気象庁非静力学モデルを用いたダウンスケール再現実験  [in Japanese] Campaign Observations of Yamase and Winter Monsoon in Tsugaru Plain, Aomori Prefecture, and Downscale Experiments Using the Nonhydrostatic Meso-scale Numerical Prediction Model of Japan Meteorological Agency  [in Japanese]

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Abstract

青森県の日本海側にある津軽平野において,冬季季節風と夏季のヤマセを対象とした高層気象観測を行った.津軽平野南部で行った冬季季節風の観測で,下層500m以下の弱風層が寒気吹き出し時に,また厚さ100m程度の薄い冷気層が季節風の一時的な止み間に観測された.津軽平野北部で行ったヤマセの観測では,高度200m付近に集中した強風が観測された.気象庁非静力学モデルを用いて,水平格子をネストして間隔を5kmと1kmに順に細かくしたダウンスケール再現実験を行った.格子間隔5kmでも冬季季節風やヤマセの鉛直構造はかなり再現されたが,1kmにするとモデルの地形が現実に近づき,鉛直スケールの小さな現象の再現が一部改善された.上流の山岳による遮蔽効果で冬季季節風時に津軽平野南部上空に弱風層が形成されること,ヤマセ時に観測された上空の強風は,ヤマセが津軽山地を越えるときのおろし風であることがわかった.

Campaign aerological observations of winter monsoon and Yamase (cool easterly observed in summer in the northeastern part of the Honshu island) were performed in Tsugaru Plain in the western part of Aomori Prefecture, Japan. We found that wind speed of winter monsoon was reduced over the southern part of Tsugaru Plain below 500 m AGL and that a very shallow (100 m) wet cold air appeared during a short period when the monsoon weakened. In Yamase observations, a thin strong wind layer concentrated around 200 m AGL in the northern part of Tsugaru Plain. Downscale experiments are performed using the nonhydrostatic meso-scale numerical prediction model of Japan Meteorological Agency (JMA) by changing horizontal resolution from 5 km to 1 km. Although vertical structure of winter monsoon and Yamase were simulated even in the 5 km run, that is a condition similar to operational prediction use of JMA, 1 km run showed fairly higher performance for simulating vertically confined thin phenomena, i.e., the shallow wet cold layer and the concentrated strong wind of Yamase. Observation and model simulation suggested that winter monsoon was weakened in the southern part of Tsugaru Plain by a shadow effect of upstream mountains and that the upper strong wind of Yamase was a down-slope wind caused by the Tsugaru mountain range in the upstream.

Journal

  • 天気

    天気 60(1), 5-14, 2013-01-31

    日本気象学会

References:  13

Keywords

Codes

  • NII Article ID (NAID)
    110009578602
  • NII NACSIS-CAT ID (NCID)
    AN00151568
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    05460921
  • NDL Article ID
    024268956
  • NDL Call No.
    Z15-35
  • Data Source
    CJP  NDL  NII-ELS  NDL-Digital 
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