Environmental Conditions Associated with Observed Snowband Structures within Northeast U.S. Winter Storms
Environmental Conditions Associated with Observed Snowband Structures within Northeast U.S. Winter Storms
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与美国东北部冬季风暴中观测到的雪带结构相关的环境条件
DOI：
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发表时间：
2018
影响因子：
3.2
通讯作者：
Nicole P. Hoban
中科院分区：
文献类型：
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作者：
Sara A. Ganetis;B. Colle;S. Yuter;Nicole P. Hoban
美国东北部冬季风暴通常表现出多个中β(L和lt；200公里)增强雷达反射率和降水波段。我们使用雷达观测、高空探测和对1996年至2016年发生在特拉华州到缅因州沿海走廊内的108个冷季(10月至4月)风暴的再分析来识别和评估各种带状结构和环境。在风暴之间可能会出现几种不同的带状结构，并且带状特征在同一风暴中的不同时间可能不同。我们使用自动和手动相结合的方法，将6小时风暴周期分类为包含长(200公里)单波段、与中尺度多波段集合共存的单波段、仅多波段和没有任何波段的雷达回波。使用0.5分贝精度和可变而不是固定阈值的雷达反射率数据表明，没有任何中尺度多波段的长单波段出现的情况很少，113个6小时周期中只有5个出现。最常见的频带构型(55%)是同时出现的单频带和多频带，通常出现在成熟气旋的西北象限。没有附近单一频带的多条频段通常出现在沿暖锋的弱中层强迫的气旋极东北象限。总体而言，与发展阶段相比，气旋闭塞后的中尺度单带和多带更常见。在大范围锋生和湿位涡环境中出现了多条带。
Northeast U.S. winter storms commonly exhibit multiple meso-β-scale (L < 200 km) bands of enhanced radar reflectivity and precipitation. We use radar observations, upper-air soundings, and reanalyses from 108 cases of cool season (October–April) storms from 1996 to 2016 that occurred within the coastal corridor from Delaware to Maine to identify and assess various banding structures and environments. Banding can occur in several configurations among storms, and banding characteristics can differ at different times within the same storm. We classified 6-h storm periods as containing long (>200 km) single bands, single bands co-occurring with sets of mesoscale multibands, multibands only, and radar echoes without any bands using a combination of automated and manual methods. Use of radar reflectivity data at 0.5-dB precision and a variable rather than a fixed threshold showed that the occurrence of long single bands without any mesoscale multibands was rare, occurring in only 5 of 113 6-h periods. The most frequently occurring band configuration (55%) was concurrent single bands and multibands, which usually were present in the northwest quadrant of mature cyclones. Sets of multibands without a nearby single band usually occurred in the northeast quadrant of a cyclone poleward of weak midlevel forcing along a warm front. Overall, mesoscale single and multibands more commonly occurred after the cyclone occluded than in the developing stages. Multibands occurred in a wide range of frontogenesis and moist potential vorticity environments.
影响因子：
3.2
作者：
Schultz D
通讯作者：
Schultz D