Numerical study of an observed orogenic mesoscale convective system. Part 1: simulated genesis and comparison with observations

Abstract

The interaction of topographically induced thermally and mechanically driven diurnal flow regimes in the lee of the Rockies is shown to lead to the growth of a mesoscale convective system (MCS). An orogenic MCS observed during the 1977 combined South Park Area Cumulus Experiment and High Plains Experiment is numerically simulated with a two-dimensional nonhydrostatic cloud model covering spatial scales of 1000 km. In this numerical investigation, mesoγ-, mesoβ-, and mesoα-scales of motion are represented simultaneously. As a result, interesting features of cloud-mesoscale interaction are predicted that cannot be represented in cloud parameterization frameworks. Based on the results of this simulation, a six-stage conceptual mode of orogenic development is given. -Authors