This page contains microphysical and kinematic data collected from the UND Citation for the 990126 event. This work is a collaborative effort between the CSU Radar Meteorology Group and Jeff Stith and NCAR ATD.
The plots below show a sample of hydrometeors (shadow images) collected from the PMS 2D-C probe as the Citation penetrated a developing cell ahead of the squall line around 21:04 UTC (Click here to see a radar cappi plot with overlaid Citation flight tracks at 2100 UTC - note that the Citation flight track through the cell of interest is along y=38-40km and in between x=-12.5 to x=-13km). The shadow images show an abundance of 1-2 mm drops. Radar cross sections suggest that some of the drops at the flight level of the Citation (-2 to -3 C) were frozen or in the process of freezing; however, it's not clear from the shadow images that the PMS actually sampled frozen drops. Moreover, the polarimetric data (ZDR), suggests that at least a few larger drops were present in this cell.
The plot below shows raw vertical velocities, filtered vertical velocity (to match the filtering done on TOGA and S-pol Doppler velocity fields) and Liquid Water Content (LWC) for a cell penetration between 2050 and 2051 UTC on 990126 (see CAPPI and flight track at 2050 UTC; and vertical cross section at X=-19 km). Note that the filtered maximum updraft is within 1 m/s of that retrieved from the dual-Doppler retrieval. However, the absolute maximum updraft (unfiltered) sampled by the Citation on this leg is a factor of two higher than that of the coarser dual-Doppler gridded vertical velocity.
