4.3
Dynamical fundamentals: some recent advances
ME McIntyre, University of Cambridge, Cambridge, United Kingdom
The Ed Lorenz Symposium is a wonderful opportunity to revisit fundamentals as well as to note recent conceptual and theoretical advances. The global-scale atmosphere is a turbulent, ultra-high Reynolds number fluid system, though radiation-stress dominated rather than eddy-viscosity dominated. Recognition of this simple fact -- a consequence of the long-range character of wave-induced momentum transport, as distinct from short-range turbulent transport -- was the key to solving some of the great atmospheric-science enimas of the 1960s. They included the "negative viscosity" enigma noted by Victor Starr and clearly flagged as an enigma by Ed Lorenz at the end of his celebrated General Circulation monograph. Also solved, through recognizing radiation-stress dominance, were the enigmas of the quasi-biennial oscillation and the cold summer mesopause. The latter is now understood as refrigeration due to wave-driven "gyroscopic pumping" (leading, in turn, to a breakthrough in understanding the Sun's internal lithium-burning circulation and differential rotation). Fundamental to all these conceptual advances are the notions of potential-vorticity inversion and of gravity and Rossby wave propagation, in turn dependent on the notion of "slow quasimanifold" (where Ed contributed much pioneering thinking), and of wave-induced momemtum flux (as distinct from the "wave momemtum myth", the myth that waves generically possess and deposit momentum). Further recent advances toward understanding the slow quasimanifold and wave-induced momemtum fluxes will be reported, including a novel system of "hyperbalance equations".
Session 4, Lorenz Symposium IV
Thursday, 13 January 2005, 3:30 PM-5:30 PM
Previous paper Next paper