Lake-Induced Mesoscale Disturbances

“湖面效应风暴”在天气预报员中广为人知。在秋末冬初，当来自加拿大的冷空气流经五大湖上空时，五大湖仍然相对温暖，湖的背风面有时会出现大范围的云层和阵雪。前人的工作表明，这些风暴一般具有浅的垂直结构，并且经常在没有任何高层动力强迫的情况下发展。因此，人们认为，来自湖泊的感热通量和表面摩擦共同起到了作用。然而，这些风暴是被迫现象吗？有没有什么不稳定的机制在起作用？Shirer教授和Fritsch教授将使用复杂的原始方程模型进行数值模拟，并使用非线性光谱模型选择性地研究物理，他们将解决这些问题。

"Lake.effect storms" are well known among weather forecasters. During late autumn and early winter when cold air from Canada flows over the Great Lakes, which are still relatively warm, extensive cloudiness and snow showers sometimes occur on the lee side of the lakes. Previous work has shown that these storms generally have a shallow vertical structure and frequently develop without any upper.level dynamical forcing. The sensible heat flux from the lakes and the surface friction collectively, so thought, play a role. However, are these storms a forced phenomenon? Is there any instability mechanism at work? Using a sophisticated primitive equation model for numerical simulations and a nonlinear spectral model for examining the physics selectively, Professors Shirer and Fritsch will address these questions.