Downstream Suppression of Baroclinic Waves

The nonlinear downstream development of baroclinic instability

The downstream development in both space and time of baroclinic instability is studied in a nonlinear channel model on the f -plane. The model allows the development of the instability to be expressed on space and time scales that are long compared to the growth rates and wavelengths of the most unstable wave. The unstable system is forced by time-varying boundary conditions at the origin of th...

Physical Simulation of Baroclinic Waves and Vortices in the Atmosphere

Dissipative Energization of Baroclinic Waves by Surface Ekman Pumping

A two-layer quasi-geostrophic model is used to study the effect of lower boundary Ekman pumping on the energetics of baroclinic waves. Although the direct impact of the Ekman pumping is to damp the total eddy energy, either the eddy available potential energy (EAPE) or the eddy kinetic energy (EKE), individually, can grow due to the Ekman pumping. Growth of EAPE is favored if the phase differen...

Lyapunov, Floquet, and singular vectors for baroclinic waves

The dynamics of the growth of linear disturbances to a chaotic basic state is analyzed in an asymptotic model of weakly nonlinear, baroclinic wave-mean interaction. In this model, an ordinary differential equation for the wave amplitude is coupled to a partial differential equation for the zonal flow correction. The leading Lyapunov vector is nearly parallel to the leading Floquet vector φ1 of ...

A Comparison of the Downstream Predictability Associated with ET and Baroclinic Cyclones

Individual case studies have shown that extratropical transition (ET) is associated with a decrease in the skill of subsequent downstream numerical weather prediction model forecasts. The degraded performance is often associated with the uncertainty that could originate in how the outflow from the TC impinges on the midlatitude waveguide, leading to the generation of a Rossby wave packet. Moreo...