4A.3 Airborne Doppler radar measurement of the sea surface and winds in hurricanes (2009

4A.3

Airborne Doppler radar measurement of the sea surface and winds in hurricanes

S.J. Frasier, U. Massachusetts, Amherst, MA; and T. Chu, J. McManus, R. Contreras, P. S. Chang, and J. Carswell

Airborne measurements of sea-surface backscatter and atmospheric

volume reflectivity and Doppler velocity are discussed. The Imaging

Wind and Rain Airborne Profiler (IWRAP) developed by the University of

Massachusetts has been deployed on the NOAA WP-3D research aircraft

for hurricane observations over the past several years. IWRAP

operates at C-band and Ku-band, which are the frequencies commonly

used for wind-vector scatterometry. IWRAP scans conically below the

aircraft at a variety of incidence angles, but most commonly, at 30

and 50 degrees. Range resolution is typically 30 m, and angular

resolution is approximately 3 deg. Research applications to date have

focused on surface wind retrievals via scatterometry, however

boundary-layer precipitation and wind structures are also well

observed.

Since 2005, a data acquisition upgrade has permitted finer resolution

observations, which are now being processed for availability to the

hurricane and air-sea interaction research communities. This year,

pulse compression has been implemented to enable operations at higher

altitudes and in heavier precipitation. An overview of recent and

current observations and data sets is presented.