Evaluation of radar multiple scattering effects in Cloudsat configuration A. Battaglia1, M. O. Ajewole2, and C. Simmer3 1Meteorological Institute, University of Bonn, Bonn, Germany 2Department of Physics, Federal University of Technology, Akure, Nigeria 3Meteorological Institute, University of Bonn, Bonn, Germany
Abstract. MonteCarlo simulations
have been performed
to evaluate the importance of
multiple scattering effects in co- and cross-polar radar returns
for 94 GHz radars in Cloudsat and airborne configurations.
Thousands of vertically structured profiles derived from some different
cloud resolving models are used as a test-bed. Mie theory
is used to derive the single scattering properties of the atmospheric
Multiple scattering effects in the co-polar channel (reflectivity
enhancement) are particularly elusive, especially in
airborne configuration. They can be
quite consistent in satellite configurations, like CloudSat,
in regions of high attenuation and in
the presence of highly forward scattering layers associated with
snow and graupel
When the cross polar returns are analysed [but note that
CloudSat does not
measure any linear depolarization ratio (LDR hereafter)], high LDR values
appear both in space and in airborne configurations.
The LDR signatures are footprints of
multiple scattering effects;
although depolarization values as high as −5 dB
can be generated including non-spherical particles in
single scattering modelling,
multiple scattering computations can produce values close
to complete depolarization (i.e. LDR=0 dB).
Our simulated LDR profiles from an air-borne platform
well reproduce, in a simple frame,
some experimental observations collected during the Wakasa Bay experiment.
Since LDR instrumental
uncertainties were not positively accounted for during that experiment,
more focused campaigns with air-borne polarimetric radar
Multiple scattering effects can be important for CloudSat applications
like rainfall and snowfall retrievals since
single scattering based algorithms
will be otherwise burdened by positive biases.
Citation: Battaglia, A., Ajewole, M. O., and Simmer, C.: Evaluation of radar multiple scattering effects in Cloudsat configuration, Atmos. Chem. Phys., 7, 1719-1730, doi:10.5194/acp-7-1719-2007, 2007.