Wind as a Geomorphic Agent - Cal State LA

Wind as a Geomorphic Agent
Wind velocities are ______________ near the ground surface
a. highest
b. near zero*
c. fluctuate from near zero to greater than 100 mph
d. about 10 mph
Wind erosion will increase when
a. the rate of velocity increases slowly above the ground surface
b. the rate of velocity stays constantly low above the ground surface
c. the rate of velocity increase reaches 10 mph above the ground surface
d. the rate of velocity increases rapidly above the ground surface*
Surface roughness such as that associated with vegetation will
a. accelerate wind erosion
b. decrease wind erosion*
c. none of these, surface roughness does not impact wind erosion
Grains are moved by wind through which process?
a. saltation
b. suspension
c.surface creep
d. all of these*
This is not an erosional landform produced by winds
a. dune*
b. deflation hollows
c. desert pavement
d. yardang
Generally, the steepest portion of the dune is
a. windward slope
b. slipface*
c. crest
Dunes covered by very little vegetation probably indicates that the dune is
a. unstable or active*
b. stable or non-active
Barchans form in areas with strong unidirectional winds and a large sand supply
a. True
b. False*
The points or horns of a parabolic dune point
a. upwind*
b. downwind
c. in a direction perpendicular to wind
d.all of these
Longitudinal dunes form in areas with one prevailing wind direction.
a. True
b. False*
In a sandstorm, ___ is the dominant mode of particle movement.
a. saltation*
b. suspension
c. siltation
d. laminar flow
Yardangs are formed when wind
a. removes all fine particles and exposes the flat bedrock
b. deposits sand in the form of a ridge
c. leaves a pavement of flat pebbles on the ground surface
d. cuts troughs into soft bedrock leaving a ridge of that rock*
During deflation, what types of particles are carried away most easily?
a. sand
b. coarsest
c. finest*
d. roundest