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Dynamics Gerrit Lohmann. Dynamics for the atmosphere-ocean system Theory, numerical models & statistical data analysis Concepts of flow, energetics, vorticity, wave motion Atmosphere: extratropical synoptic scale systems Oceanic wind driven and thermohaline circulation. Fluid dynamics.
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Dynamics Gerrit Lohmann Dynamics for the atmosphere-ocean system Theory, numerical models & statistical data analysis Concepts of flow, energetics, vorticity, wave motion Atmosphere: extratropical synoptic scale systems Oceanic wind driven and thermohaline circulation
Fluid dynamics properties of mass, momentum and energy in a control volume Substatial or material derivative
Equations of motion http://anusf.anu.edu.au/~sjm651/meng/thesis/node2.html Practical: Laptop?
Dynamical Equationscartesian system Momentum budget For a fluid, Isaac Newton's second law „mass times acceleration equals the sum of forces“ is better stated per unit volume with density replacing mass. In the absence of rotation, the resulting equations are called the Navier-Stokes equations. real forces and apparent forces
real forces and apparent forces • apparent forces which account for the acceleration (the change in direction) of our frame of reference and which accounts for the observed motions of air/water parcels. • real forces - those which exist regardless of our frame of reference
Real Forces • Pressure • Graviatation • Friction
Pressure • Air moves because of an imbalance in the forces acting on the air molecules. In the warm column, the pressure at the level of 5,500 meters was greater than originally (600 hPa rather than 500 hPa). In the cold column, the pressure at the level of 5,500 meters was less than originally (400 hPa rather than 500 hPa).
Motion The difference in pressure between the two columns initiated air molecules to begin flowing from the regions of higher pressure in the warm column to the lower pressure in the cold column. If we consider this process on a hemispheric scale, on an ideal planet (only the pressure gradient forces and gravity acting, no Coriolis force, Centrifugal Force or friction) and the surface is the same substance with no mountains, we should see a similar pattern like
Formalism of a rotating frame Capital letters: inertial framework of reference Rotation