Here we study the balance of forces typical of atmospheric vortices and severe weather across scale, using the Rossby number as a guide. The activity parallels that taken in our ‘radial inflow’ laboratory experiment.
A detailed description of the activity is in weather_xtremes_atmosphere and weather_xtremes_slides.
Relevant theory and discussion of the balance of forces can be found in the reference materials.
Estimating the Rossby number as a function of scale
Estimate the Rossby number of various vortices in the atmosphere in a manner which is exactly analogous to that used in the laboratory experiments by tracking ‘virtual’particles in the evolving wind patterns using the EsGlobe – see EsGlobe instructions.
- Planetary scale – the jet stream – see example movie.
- Mid-latitude cyclones – blizzards and Nor’easters – see example of the Blizzard of Jan 4, 2018.
- Tropical cyclones – hurricanes – see Harvey ( August, 2018).
Jet stream – geostrophic balance
Compare distribution of climatology of zonal wind and north-south pressure gradient for zonal averages, using the Esglobe-atmopsheric-climatology.
Hurricane flow – balance of forces
Choose a hurricane and plot the observed winds and Rossby Number in function of radius as described in the scatterometer-instructions.
Discuss how the hurricane data compare and contrast with the radial inflow experiment.
List of interesting hurricane case studies is available here.