BOUNDARY LAYER STRUCTURE AND DYNAMICS
GPS SONDE PROFILES:
This project focuses assessing boundary layer structure and
air-sea flux behavior in tropical cyclones. A large database of
GPS sonde profiles provides a rich source of information to
determine bulk profile and surface layer characteristics
needed to understand physical processes in the hurricane
boundary layer.

STRATEGIES:
´ Invoking similarity and ergodicity, large numbers of
profiles in similar conditions are averaged to provide
measurements of surface roughness and drag coefficient.
´ The values are then investigated for behavior as a
function of wind speed, storm relative location, and
water depth.
RESULTS:
´ The drag coeficient exhibits an initial increase with wind
speed for winds up to hurricane force followed by a
decrease as winds continue to increase.
´ When broken down by radius, this behavior is confined
to radii beyond 30 km while inner radii exhibit relatively
small variations in drag with wind speed.
´ When broken down by storm-relative azimuth, the drag
coefficient on the front left side of the storm shows
much larger values than the other storm quadrants.