Numerical simulations of mountain waves and rotors observed during T-REX

Results from numerical simulations of mountain waves and rotors over the Sierra Nevada mountains, USA, will be compared with airborne and ground based observations made during the recent Terrain induced Rotor Experiment (T-REX). The numerical model employed for this study is the Met Office Unified Model. Series of nested simulations for selected T-REX Intensive Observation Periods (IOPs) will be conducted, the horizontal resolution of the inner-most domain being less than 1 km.

The numerical predictions will be compared to observations of mountain waves obtained with the UK FAAM BAe-146 research aircraft, with near-surface flow observations made using a network of automatic weather stations (AWSs) and with radiosonde and dropsonde measurements. Of specific interest are the temporal and spatial variations observed in the wave field, the location of separation points at the upstream foot of the rotors and the three-dimensional structure of the rotors.