Vortex Formation in Mesoscale Convective Systems

一段时间以来，人们已经知道，热带中尺度对流系统可能发展出足够强度的旋转环流，从而转变为热带气旋。最近，中纬度中尺度系统形成的中尺度涡旋比它们的母体中尺度对流系统寿命更长。这些中尺度涡旋对随后对流天气的位置、时间和严重程度有重要影响。由于中尺度涡旋的大小和振幅相对较小，目前的业务天气系统通常无法探测到它们，而且对其重要的物理过程也没有很好的了解，因此在业务预报模式中也没有考虑到它们。利用最先进的中尺度模式，首席研究员将对中纬度大陆和热带海洋地区中尺度涡旋的形成进行一系列数值模拟。研究结果将有助于加深对中尺度对流系统最初发展为旋转环流的物理过程的理解。这种认识可能会大大提高我们预测对流天气系统及其伴随的恶劣天气（如暴雨、冰雹、大风和龙卷风）的能力。

It has been known for some time that mesoscale convective systems in the tropics may develop rotational circulations of sufficient strength that the systems transform into tropical cyclones. More recently, mid- latitude mesoscale systems have been shown to form mesoscale vortices which outlive their parent mesoscale convective system. It also has been established that these mesoscale vortices can have significant impacts on the location, timing and severity of subsequent convective weather. Due to their relatively small size and amplitude, mesoscale vortices typically are not sensed by the current operational weather system and the important physical processes are not well understood and, therefore, not accounted for in operational prediction models. Using a state-of-the-art mesoscale model, the Principal Investigator will perform a series of numerical simulations of the formation of mesoscale vortices in both mid-latitude continental and tropical maritime regimes. Results will lead to increased understanding of the physical processes by which mesoscale convective systems initially develop rotational circulations. This understanding may lead to significant improvements in our ability to forecast convective weather systems and their attendant severe weather such as heavy rainfall, hail, high winds and tornadoes.