Orographic Effects on Cold Fronts

观测表明，地形对大气锋面--它们的强度、传播和降水--有很大影响，但锋面和地形之间相互作用的动力学仍未得到很好的了解。特别是，在一个发展中的斜压系统存在的情况下，山和锋面的相互作用还没有被研究过。根据这项拨款，首席研究人员将使用原始方程数值模型来探索这种相互作用的动力学，并分离涉及的物理过程。冷锋将受到与斜压波的非线性演化有关的剪切变形的强迫。温度梯度的包含提供了比以前探索的更现实的场景。在有湿和无湿的情况下，将研究山脉大小和大气稳定性的影响，以及边界过程的作用及其对垂直运动场的影响。最后，首席调查员将研究山脉对与锋面有关的降水的影响。

Observations have shown that orography significantly affects atmospheric fronts - their strength, propagation and precipitation - but the dynamics of the interaction between a front and orography are still not well understood. In particular, the interaction of the mountain and a front in the presence of a developing baroclinic system has not been investigated. Under this grant, the principal investigator will use a primitive equation numerical model to explore the dynamics of this interaction and to isolate the physical processes involved. The cold front will be forced by the shearing deformation associated with the nonlinear evolution of a baroclinic wave. The inclusion of temperature gradients provides a more realistic scenario than has been explored previously. The effects of mountain size and atmospheric stability, both in the presence and absence of moisture, will be investigated as well as the role of boundary processes and their effect on the vertical motion field. Finally, the principal investigator will study the effect of the mountains on precipitation associated with the front.***