Preliminary estimates of vertical momentum flux

Preliminary results of themomentum flux and flux divergence during a transient episode, as a jet stream moved over the radar are given. The zonal and meridional momentum flux and flux divergences displayed remarkable continuity with altitude in time, increasing in intensity as lee waves and other gravity-wave activity developed while the jet stream approached. The momentum flux values observed compare favorably with aircraft measurements made over similar topography, at least during the early part of the day. The accelerations due to the momentum flux divergence seem rather large at first glance, especially for the late part of the day. However, there may be compensating forces due to effects not considered here, such as transverse circulations or, scales of motion to small to be resolved by these data.