A Comparison of X-band Polarization Parameters with Aircraft Measurements of Two Comma Head Winter Cyclones

The Profiling of Winter Storms (PLOWS) field campaign during the winters of 2008-2009 and 2009-2010 focused on improving the understanding of dynamic and microphysical processes occurring in continental winter cyclones in the middle latitudes. During PLOWS, the NSF/NCAR C-130 aircraft made multiple passes at varying altitudes through the comma head of the 15 and 22 February 2010 cyclones as they moved over the Mobile Alabama X-band (MAX) dual-polarization radar. The radar was performing Range Height Indicator (RHI) scans in the same plane as the C-130 flight track.

Several in-situ cloud microphysical probes, including a particle volume monitor probe (PVM) for measuring liquid water content and two-dimensional cloud and precipitation probes (2DC and 2DP) for measuring cloud and precipitation particle size and habit distributions, acquired data during the C-130 flights. When data from these probes are combined with the ground-based X-band radar measurements of differential reflectivity (Z_dr), correlation coefficient (ρ_hv), and radial velocity, great insight into the microphysical processes and kinematic structures of the clouds can be obtained. The best estimates of cloud particle parameters (size and shape distributions, aspect ratios, projected areas, liquid water contents) are used to represent particles as soft spheroids, which, when combined with T-matrix theory provides estimates of reflectivity (Z) and Z_dr which can be compared against measurements of Z and Z_dr at the aircraft's position by the MAX radar.