Influences of Orography and Coastal Geometry on a Transverse-Mode Sea-Effect Snowstorm over Hokkaido Island, Japan
Influences of Orography and Coastal Geometry on a Transverse-Mode Sea-Effect Snowstorm over Hokkaido Island, Japan
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DOI：
10.1175/mwr-d-17-0286.1
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发表时间：
2018-07-01
影响因子：
3.2
通讯作者：
Fujiyoshi, Yasushi
中科院分区：
文献类型：
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作者：
Campbell, Leah S.;Steenburgh, W. James;Fujiyoshi, Yasushi
在日本海上空产生的海洋效应暴风雪在整个冬季产生持续的、经常是强降雪，影响了日本北方和中部的下游社区。在这里，我们使用的观测和天气研究与预报（WRF）模式模拟，以检查所产生的横向模式的海洋效应雪带，与山区地形的相互作用，石狩湾，北海道岛，日本，2014年1月12日的降水分布。这里观察到的带是水平对流卷，垂直于平均气流，宽约10公里，长约100公里。该带接近石狩湾的间隔类似于10-16分钟，加强，因为他们通过一个准静止的，细长的增强区域，包围了积丹半岛，并延伸到石狩平原。水凝平流，通过上升区域的积丹半岛的东北坡，和沿着顺时针转向的边界层定向切变的轨迹，有助于持续降水增强沿着曲线在细长的增强区域入口附近的石狩湾。下游，由沿海山脉的地形流偏转，可能加剧热和粗糙度梯度沿着的积丹半岛的海岸线，产生收敛和上升沿着拉长增强区。这项研究表明，下游地形对海效应暴风雪的影响，并提高在这个和其他湖泊和海效应地区的降雪预测的影响。
Sea-effect snowstorms generated over the Sea of Japan produce consistent and often heavy snowfall throughout the winter season, impacting downstream communities in northern and central Japan. Here, we use observations and Weather Research and Forecasting (WRF) Model simulations to examine the precipitation distribution produced by transverse-mode sea-effect snowbands that interacted with the mountainous terrain circumscribing Ishikari Bay, Hokkaido Island, Japan, on 12 January 2014. The bands observed here were horizontal convective rolls aligned normal to the mean flow and were similar to 10 km wide and up to similar to 100 km long. The bands approached Ishikari Bay at intervals of similar to 10-16 min, intensifying as they progressed through a quasi-stationary, elongated enhancement region that paralleled the Shakotan Peninsula and extended into the Ishikari plain. Hydrometeor advection, through an ascent region over the northeast slope of the Shakotan Peninsula, and along clockwise-turning trajectories steered by the boundary layer directional shear, contributed to sustained precipitation enhancement along a curve in the elongated enhancement region near the entrance to Ishikari Bay. Downstream, orographic flow deflection by the coastal mountains, likely accentuated by thermal and roughness gradients along the Shakotan Peninsula's shoreline, produced convergence and ascent along the elongated enhancement region. This study demonstrates the impact of downstream topography on sea-effect snowstorms and has implications for improving the prediction of snowfall in this and other lake- and sea-effect regions.