Simulations of Polarimetric, X-Band Radar Signatures in Supercells. Part II: Z(DR) Columns and Rings and K-DP Columns

摘要

A high-resolution numerical model and polarimetric forward operator allow one to examine simulated convective storms from the perspective of observable polarimetric radar quantities, enabling a better comparison of modeled and observed deep moist convection. Part I of this two-part study described the model and forward operator used for all simulations and examined the structure and evolution of rings of reduced copolar cross-correlation coefficient (i.e., rho(hv) rings). The microphysical structure of upward extensions of enhanced differential reflectivity (Z(DR) columns and Z(DR) rings) and enhanced specific differential phase (K-DP columns) near and within the updrafts of convective storms serve as the focus of this paper. In general, simulated Z(DR) columns are located immediately west of the midlevel updraft maximum and are associated with rainwater lofted above the 0 degrees C level and wet hail/graupel, whereas Z(DR) rings are associated with wet hail located near and immediately east of the midlevel updraft maximum. The deepest areas of Z(DR). 1 dB aloft are associated with supercells in the highest shear environments and those that have the most intense updrafts; the upper extent of the Z(DR) signatures is found to be positively correlated with the amount and mean-mass diameter of large hail aloft likely as a by-product of the shared correlations with updraft intensity and wind shear. Large quantities of rain compose the K-DP columns, with the size and intensity of the updrafts directly proportional to the size and depth of the K-DP columns.