On the Relationship of Cold Pool and Bulk Shear Magnitudes on Upscale Convective Growth in the Great Plains of the United States
On the Relationship of Cold Pool and Bulk Shear Magnitudes on Upscale Convective Growth in the Great Plains of the United States
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DOI：
10.3390/atmos12081019
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发表时间：
2021-08
期刊：
影响因子：
2.9
通讯作者：
Zachary A. Hiris;W. Gallus
中科院分区：
文献类型：
--
作者：
Zachary A. Hiris;W. Gallus
高层对流增长仍然是对流演变的一个鲜为人知的方面，数值天气预报模式难以准确地描述对流形态。为了更好地理解一些促进高级别增长的物理机制，使用天气研究和预报(WRF)模式模拟了2016年美国大平原上的30个暖季对流事件，以确定高级别增长环境和非高级别增长环境的差异。此外，在不同的热力学环境和风廓线下完成了布莱恩云模式(CM1)的敏感性测试，以检查对高端增长的影响。WRF模拟表明，在对流开始后的最初几个小时内产生高层对流增长的情况下，冷池比没有高层对流增长的情况要强得多。相反，垂直风切变强度与MCS或非MCS事件都没有统计上的显著关系。这进一步得到了CM1模拟的支持，在该模拟中，使用WRF MCS探测的测试在所有进行的测试中发展了一个大对流系统，包括使用非MCS运动学轮廓的一次测试。同样，非高档增长事件的CM1模拟没有生成MCS，即使使用MCS运动学轮廓也是如此。总体而言，这些结果表明，在决定大平原高端增长潜力方面，近风暴和对流前的热力环境可能比运动学发挥更大的作用。
Upscale convective growth remains a poorly understood aspect of convective evolution, and numerical weather prediction models struggle to accurately depict convective morphology. To better understand some physical mechanisms encouraging upscale growth, 30 warm-season convective events from 2016 over the United States Great Plains were simulated using the Weather Research and Forecasting (WRF) model to identify differences in upscale growth and non-upscale growth environments. Also, Bryan Cloud Model (CM1) sensitivity tests were completed using different thermodynamic environments and wind profiles to examine the impact on upscale growth. The WRF simulations indicated that cold pools are significantly stronger in cases that produce upscale convective growth within the first few hours following convective initiation compared to those without upscale growth. Conversely, vertical wind shear magnitude has no statistically significant relationship with either MCS or non-MCS events. This is further supported by the CM1 simulations, in which tests using the WRF MCS sounding developed a large convective system in all tests performed, including one which used the non-MCS kinematic profile. Likewise, the CM1 simulations of the non-upscale growth event did not produce an MCS, even when using the MCS kinematic profile. Overall, these results suggest that the near-storm and pre-convective thermodynamic environment may play a larger role than kinematics in determining upscale growth potential in the Great Plains.