Characteristics of gravity waves generated in the jet-front system in a baroclinic instability simulation

Three groups of gravity waves appear around the high-latitude surface trough at the mature stage of the baroclinic wave. They have horizontal and vertical wavelengths of 40-400 and 2.9-9.8km, respectively, in the upper troposphere.

The two-dimensional phase-velocity spectrum of the waves is arc shaped with a peak at 17m s⁻¹ eastward. These waves have difficulty in propagating upward through the tropospheric westerly jet. At the breaking stage of the baroclinic wave, a midlatitude surface low is isolated from the higher-latitude trough, and two groups of quasi-stationary gravity waves appear near the surface low.