Journal of the Korean earth science society (한국지구과학회지)

The Korean Earth Science Society (한국지구과학회)
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A Numerical Study on the Formation Mechanism of a Mesoscale Low during East-Asia Winter Monsoon

  • Koo, Hyun-Suk (Department of Environmental Conservation and Disaster Prevention Keimyung University) ;
  • Kim, Hae-Dong (Department of Environmental Conservation and Disaster Prevention Keimyung University) ;
  • Kang, Sung-Dae (Climate Prediction Division, Korea Meteorological Administration) ;
  • Shin, Dong-Wook (Center for Ocean-Atmospheric Prediction Studies (COAPS), Florida State University)
  • Published : 2007.09.30
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Abstract

Mesoscale low is often observed over the downstream region of the East Sea (or, northwest coast off the Japan Islands) during East-Asia winter monsoon. The low system causes a heavy snowfall at the region. A series of numerical experiments were conducted with the aid of a regional model (MM5 ver. 3.5) to examine the formation mechanism of the mesoscale low. The following results were obtained: 1) A well-developed mesoscale low was simulated by the regional model under real topography, NCEP reanalysis, and OISST; 2) The mesoscale low was simulated under a zonally averaged SST without topography. This implies that the meridional gradient of SST is the main factor in the formation of a mesoscale low; 3) A thermal contrast ($>10^{\circ}C$) of land-sea and topography-induced disturbance served as the second important factor for the formation; 4) Paektu Mountain caused the surface wind to decelerate downstream, which created a more favorable environment for thermodynamic modification than that was found in a flat topography; and 5) The types of cumulus parameterizations did not affect the development of the mesoscale low.

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References

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