18 September 2009
Jennifer Davison, University of Illinois, Urbana-Champaign
Where's water? Enhanced moisture retrievals using S-band radar
In addition to being the most significant green house gas, water vapor
is critical for the production of severe convection. Vertical profiles
of water vapor are necessary for constructing radiation absorption profiles
as well as predicting the likelihood of severe convection. The traditional
method for measuring water vapor in the vertical is through the use of
radiosondes, each of which yields a single vertical profile. In the
contiguous US, these are typically launched only twice a day from 69 different
locations.
In order to improve our knowledge of water vapor profiles, a technique
utilizing the Bragg scattered returns from S-band radar was developed to
track the vertical profile of relative humidity maxima and minima. This
technique, which was initially developed in a tropical marine environment
using data from the Rain in Cumulus over the Ocean (RICO) experiment, suggests
that the current conceptual model of the suppressed tropical regime is
inadequate and a new conceptual model is proposed. Continental mid-latitude
data from the International H2O Project (IHOP) in Oklahoma was also analyzed
using this technique; comparisons with Raman lidar moisture profiles will be
presented. Furthermore, this technique can be applied to National Weather
Service radar data in near real time; as an example, results from KLVX data
for the time leading up to the Louisville flood last month will be shown.
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