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Modeling Geophysical Fluid Flows. Pete Bosler. Overview. “Geophysical Fluid Flow” Ocean & Atmosphere Physical oceanography and meteorology Across spatial scales of O(10 m) to O(1000 km) Modeling Deriving & Simplifying Numerical solutions Application and use of modeling Forecasts.
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Modeling Geophysical Fluid Flows Pete Bosler
Overview • “Geophysical Fluid Flow” • Ocean & Atmosphere • Physical oceanography and meteorology • Across spatial scales of O(10 m) to O(1000 km) • Modeling • Deriving & Simplifying • Numerical solutions • Application and use of modeling • Forecasts
State of models today • Global Models • World Meteorological Association • Ex: NOGAPS, GFS • Regional Models • Better resolution • Can resolve smaller scale phenomena • More realistic topographic interaction • Boundary conditions are an added issue
Data Input • Over Land • Satellites • Airports and automated stations • Maritime: very sparse data • Satellites • Ship observations • Islands
Mathematics • Physics of these fluids can turn out to be “not nice.” • Sensitive dependence on initial conditions • Chaotic dymanics • Discontinuities may arise • Jumps • Shocks • Singularities
Jump Example Warm Eddy North Wall Cold Eddies
Convection in a slab = Stream Function =Temperature perturbation
Precipitation vs. Updraft Updraft Velocity Rainwater Mixing Ratio Virtual temperature excess “Generation Parameter” Downward velocity of raindrops
Where to go next? Level Set Methods http://physbam.stanford.edu/~fedkiw/
References/Additional Reading • Davis, 1988, “Simplified second order Godunov-type methods” • Gottleib & Orszag, 1987, “Numerical Analysis of Spectral Methods” • Lorenz, 1963, “Deterministic Nonperiodic Flow” • Leveque, 2005, “Numerical Methods for Conservation Laws” • Malek-Madani, 1998, “Advanced Engineering Mathematics” • Rogers & Yau, 1989,“A Short Course in Cloud Physics” • Saltzman, 1962, “Finite amplitude free convection as an initial value problem” • Smoller, 1994, “Shock Waves and Reaction-Diffusion Equations” • Srivastava, 1967, “A study of the effect of precipitation on cumulus dynamics”