"Precipitation and other microphysical processes Radiatively active"
Precipitation and other microphysical processes Radiatively active clouds Convection Turbulence Gravity waves Chemical processes Scale dependence At a point, everything is simple. Continuum approximation Motion, thermodynamics Thermodynamic equilibrium holds. Averaging smooths things out. Averaging length is not necessarily the grid size Nevertheless, when we average, things get complicated. Motion, thermodynamics Thermodynamic equilibrium does not apply to the averaged state. What averaged ﬁelds are we interested in? States Temperature Water vapor Horizontal wind vector Rates Precipitation Radiation Convective and turbulent ﬂuxes of sensible heat, moisture, and momentum Things that happen when you average Mean liquid water positive even though the mean RH is less than 100% Fractional cloudiness Fluxes due to scales smaller than the averaging length What is parameterization? Needed in both numerical and analytical models Not just an engineering exercise -- not just a means to an end Not made obsolete by inﬁnitely powerful computers Compare parameterizations for geophysics and engineering. Do physicists parameterize? What does it mean to "explain" something? Kinetic theory of ideal gases --> Ideal Gas Law Speciﬁc parameterizations Deep convection Moist convective adjustment Arakawa-Schubert Kane-Fritsch Emanuel For analytical models For numerical models Stratiform clouds Smagorinsky Sundqvist Tiedtke PBL Deardorff Lilly Mellor-Yamada and follow-ons Lappen-Randall Shallow convection Betts Tiedtke Bretherton Super-parameterization First-generation Second-generation Friction under-studied problem Horizontal diffusion under-studied problem Numerics and parameterizations under-studied problem Testing parameterizations GATE and other early experiments ARM and GCSS