Numerical Simulation of Transitions in Boundary Layer Convective Structures in a Lake-Effect Snow Event
Numerical Simulation of Transitions in Boundary Layer Convective Structures in a Lake-Effect Snow Event
复制标题
湖效应雪事件中边界层对流结构转变的数值模拟
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
Neil F. Laird
中科院分区：
文献类型：
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作者：
Kevin Cooper;M. Hjelmfelt;R. Derickson;D. Kristovich;Neil F. Laird
摘要本文利用数值模拟研究了1983年12月17日密歇根湖上的一次湖效应降雪过程中观测到的边界层卷和更多的胞状对流结构之间的转换。弱湖效应非滚对流附近的东部（顺风）海岸附近观察到的第二冷锋通道之前。锋面通过后，对流边界层中的水平风速增加，随后发展成线性对流模式。此后，随着低层风速降低，对流模式变得更加立体。在所有的风廓线中都观察到了很小的定向切变。数值模拟与先进的区域预报系统模型进行了初始化与逆风探测和雷达导出的风廓线对应的三个对流结构制度。模型推导的反射率场与观测到的制度吻合得很好。这些模拟主要在初始风速剖面上有所不同。
Abstract Numerical simulations are used to study transitions between boundary layer rolls and more cellular convective structures observed during a lake-effect snow event over Lake Michigan on 17 December 1983. Weak lake-effect nonroll convection was observed near the eastern (downwind) shore preceding passage of a secondary cold front. After frontal passage horizontal wind speeds in the convective boundary layer increased, with subsequent development of linear convective patterns. Thereafter the convective pattern became more three-dimensional as low-level wind speeds decreased. Little directional shear was observed in any of the wind profiles. Numerical simulations with the Advanced Regional Prediction System model were initialized with an upwind sounding and radar-derived wind profiles corresponding to each of the three convective structure regimes. Model-derived reflectivity fields were in good agreement with the observed regimes. These simulations differed primarily in the initial wind speed profiles...