Cross-Barrier Flow during Orographic Precipitation Events: Results from MAP and IMPROVE
Cross-Barrier Flow during Orographic Precipitation Events: Results from MAP and IMPROVE
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DOI：
10.1175/jas3554.1
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发表时间：
2005-10
影响因子：
3.1
通讯作者：
S. Medina;B. Smull;R. Houze;M. Steiner
中科院分区：
文献类型：
--
作者：
S. Medina;B. Smull;R. Houze;M. Steiner
摘要在欧洲阿尔卑斯山和俄勒冈州喀斯喀特山脉的锋面暴雨过境期间收集的地面和机载多普勒雷达数据显示出典型的跨障流动和降水模式。山顶以下的稳定分层阻挡(或部分阻挡)低动量流与高空的强跨障流动被一个垂直风切变集中层分开。这个切变层向上向山顶倾斜，并在风暴经过山脉时持续几个小时。这种模式在不同的情况下和从一个山脉到另一个山脉都非常相似。在这些情况下，地形上增强的降水呈现层状结构，以雷达亮带为标志，该亮带经常下降到紧邻迎风山坡的较低高度(表明局部较凉爽)。地形引起的重力波产生强烈的下坡气流和降水溢出到...
Abstract Ground-based and airborne Doppler radar data collected during passage of frontal rainstorms over the European Alps and Cascade Mountains of Oregon are found to exhibit characteristic cross-barrier flow and precipitation patterns. A stably stratified layer of blocked (or partially blocked) low-momentum flow below mountain-crest level is separated from strong cross-barrier flow aloft by a concentrated layer of vertical wind shear. This shear layer slopes upward toward the mountain crest and persists for several hours as the storm passes over the mountain range. This pattern is remarkably similar from case to case and from one mountain range to the other. The orographically enhanced precipitation in these cases exhibits stratiform structure, marked by a radar bright band, which often drops to a lower height (indicating locally cooler conditions) immediately adjacent to the windward mountain slopes. A terrain-induced gravity wave produces strong downslope flow and spillover of precipitation onto the ...