Mechanisms supporting long-lived episodes of propagating nocturnal convection within a 7-day WRF model simulation
Mechanisms supporting long-lived episodes of propagating nocturnal convection within a 7-day WRF model simulation
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DOI：
10.1175/jas3768.1
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发表时间：
2006-10
影响因子：
3.1
通讯作者：
S. Trier;C. Davis;D. Ahijevych;M. Weisman;G. Bryan
中科院分区：
文献类型：
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作者：
S. Trier;C. Davis;D. Ahijevych;M. Weisman;G. Bryan
摘要采用大区域显式对流模拟方法研究了美国中部连续一周纬向传播强降水事件的夜间对流的生命周期。与相关联暖季对流的气候学研究类似，最长的降水事件在下午晚些时候开始于大平原西部（105°-100 ° W），在大平原中部（100°-95 ° W）的夜间达到最大强度，在中西部（95°-85 ° W）的日出前后或稍晚减弱。最长的事件显示出平均纬向相速度为1.20 m s−1，与该时期的雷达观测结果一致。合成分析的生命周期的五个长期存在的夜间降水事件表明，对流都发展，然后沿沿着东西向的低对流层锋区向东传播。高θe空气层的高度约为2.2公里，有助于维持对流...
Abstract A large-domain explicit convection simulation is used to investigate the life cycle of nocturnal convection for a one-week period of successive zonally propagating heavy precipitation episodes occurring over the central United States. Similar to climatological studies of phase-coherent warm-season convection, the longest-lived precipitation episodes initiate during the late afternoon over the western Great Plains (105°–100°W), reach their greatest intensity at night over the central Great Plains (100°–95°W), and typically weaken around or slightly after sunrise over the Midwest (95°–85°W). The longest-lived episodes exhibit average zonal phase speeds of ∼20 m s−1, consistent with radar observations during the period. Composite analysis of the life cycle of five long-lived nocturnal precipitation episodes indicates that convection both develops and then propagates eastward along an east–west-oriented lower-tropospheric frontal zone. An elevated ∼2-km-deep layer of high-θe air helps sustain convect...