Taka Iguchi
Affiliation: UMCP and NASA/GSFC
Event Date: Tuesday, November 10, 2009
Location: Bldg #33 Room F225
Time: 11:00:00
Evaluation of cloud microphysics simulated by a SBM meso-scale model with observation uUsing shipborne Doppler and spaceborne W-band radars
Radar reflectivity factors measured by W-band radars are directly compared with the corresponding values calculated from
a three-dimensional non-hydrostatic meso-scale model coupled with a bin-based cloud microphysical scheme. Three case
studies become the objects: one targets a part of shipborne observation using 95 GHz Doppler radar over the Pacific Ocean
near Japan in May 2001; other two aim at two short segments of spaceborne observation by CloudSat cloud profiling radar around
Japan in November 2006. In general, the simulations reproduce features of vertical structures of reflectivity factor and
Doppler velocity, whereas an overestimation in ice clouds layers is a main common issue of the reproductivity. A frequency
analysis shows a strong correlation between ice water content and its radar reflectivity in the simulation, similar to
their relations shown in prior on-site studies. By comparing with relationships by prior studies, the simulated
reflectivity overestimates the observed value at the same ice water content. This discrepancy of reflectivity is supposed
to be caused by an overestimation of ice particles sizes larger than several hundred microns, whereas such large
snowflakes are necessary to produce a large Doppler velocity under the melting level. Both Ze and Doppler velocity are
never compatible after all. To identify the cause of the problems, namely overestimation of mass and/or size, needs
further validation research with other observations at composite frequencies.
