ATMOSPHERIC TIDES ON VENUS .4. TOPOGRAPHIC WINDS AND SEDIMENT TRANSPORT

Solar heat absorbed by the soil of Venus is rapidly deposited in its atmosphere. This exchange drives small diurnal temperature and pressure variations. These in turn generate periodic winds of a few meters per second and surface stresses capable of blowing sand-size grains along the surface of Venus. This paper presents a new theory of the Venus boundary layer which includes the effects of topography. Use of the mixing-length hypothesis eliminates the unknown eddy viscosity. Maps of predicted mass flux and erosion/deposition rates are presented, based on the relief measured by the Pioneer Venus orbiter. Regional slopes dominate the wind field and corresponding mass transport. Typical friction speeds are ∼19 cm/s, several times those estimated from Venera 9 and 10 anemometer data. Mean aeolian transport is generally away from the equator, contrary to the prevailing direction of wind streaks seen by the Magellan orbiter. Including a steady Hadley circulation can correct the wind direction, but not the friction speeds. © 1993 Academic Press. All rights reserved.