Applications

1. Applications • Response of a baroclinic model to thermal and orographic forcings • Observations: Horel and Wallace (1981) Wallace and Gutzler (1981)

2. Response of Baroclinic Model to Subtropical Thermal Forcing • Heat source located at 15°N • Vicinity of heating: response is consistent with fig. 2a • Upper troposphere, away from source: resembles barotropic model(fig. 1) • Wavetrain set up poleward and eastward of source • Splits at 35° latitude

3. Response of Baroclinic Model to Orographic Forcing • Mountain centered at 30°N • Structure near source consistent with theory (fig. 7) • Upper troposphere: also resembles barotropic model • Wavetrain splits at 40° latitude into a low wavenumber polar wavetrain and shorter wavelength subtropical wavetrain

4. Observations Horel and Wallace (1981) • Pattern resembles the wavetrain shown in model results • Directed first poleward, then curves eastward, and then equatorward in a great circle path

5. Observations: Wallace and Gutzler(1981) • These teleconnection patterns are also consistent with the wavetrains resulting from the model

6. Conclusions/Key Points • Vorticity perturbations created by local forcings • Wave dispersion: long wavelengths propagate poleward as well as eastward while shorter wavelengths seem to stay closer to the equator • Models: wavetrains are consistent with theory; in the upper troposphere barotropic and baroclinic models are very similar • Observations consistent with model and theory