ON THE EFFECT OF MIDAIR COLLISIONS ON AEOLIAN SALTATION

The effect of mid-air collisions on aeolian saltation is investigated using concentration profiles and grain velocities predicted by a numer ical saltation model. The probability of a mid-air collision is found to be greater at high wind speeds. It is also found that mid-air colli sions tend to reduce the number of grain/bed impacts and thus reduce t he number of ejecta near the bed; this, in turn, reduces the intensity of mid-air collisions. It is suggested that this feed-back mechanism significantly influences transport rates at high wind speeds.