Vortex Formation in Mesoscale Convective Systems

热带中尺度对流系统可能发展出强度足以转化为热带气旋的旋转环流，这一点早已为人所知。最近，中纬度中尺度系统被证明形成了比其母中尺度对流系统持续时间更长的中尺度涡旋。还证实，这些中尺度涡旋可能对随后的对流天气的位置、时间和严重程度产生重大影响。由于其相对较小的大小和幅度，中尺度涡旋通常不被当前业务天气系统感知，重要的物理过程没有得到很好的理解，因此没有在业务预测模型中考虑在内。使用最先进的中尺度模式，首席调查员将对中纬度大陆和热带海洋区中尺度涡旋的形成进行一系列数值模拟。结果将有助于加深对中尺度对流系统最初形成旋转环流的物理过程的理解。这一认识可能会大大提高我们预报对流天气系统及其伴随的暴雨、冰雹、大风和龙卷风等恶劣天气的能力。

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.