Dual-Polarization Radar Data Guide

Bonus Question 7: Review the 0.5 deg Z, ZDR, CC and KDP base data at 0434 UTC in theelongated hook echo portion of this supercell, roughly 20-22 nm range between azimuths 003-004degrees. Using what you have learned, what is your best estimate of hydrometeor type within thissample volume? (Refer to Training Aids for assistance)Answer: Z values are generally 50-55 dBZ, ZDR values are generally between +4 and +5.5 dBZ, CCvalues are generally 0.97-0.98 and KDP values are generally between 0.5 and 2.0 deg/km. Thiscombination of dual-pol base data is generally supportive of heavy rain with little or no hail present. CCvalues greater than 0.95 suggest a homogeneous hydrometeor type, and ZDR values above +4 dBZ andKDP values greater than 0.5 deg/km strongly support larger (greater than 3 mm diameter) droplet sizes,and lots of them given KDP as high as 2 deg/km. Finally, Z values from 50-55 dBZ suggest very intenserainfall rates provided the precipitation type is all liquid.Now use either the image toggle in 4 panel or Panel Combo/Rotate mode (hit the 8 key), to viewthe Hydrometeor Classification Algorithm (HCA) output for this storm at 0434 UTC. Compare theHCA output to the hydrometeor types we determined from our analysis of the dual-pol base data.Question 8: Does the HCA output agree with the most likely hydrometeor types deduced from thebase data analysis? Feel free to refer to the HCA training aid.Answer: In general, yes. The HCA depicts heavy rain in the forward flank core of the supercell, andmostly heavy rain in the hook echo region. The main precip core was tagged “RH” which is hail possiblymixed with rain, agreeing with the HCA. You will notice that in many parts of the supercell, where clearlythere is precipitation, the HCA tags many bins incorrectly as “biological”.8