Radar Cross Sections for 990126

This page contains radar cross section images (gif format) of reflectivity, polarimetric quantities (e.g., ZDR, LDR, KDP) and storm relative winds for the 990126 event. The plots utilize the the high resolution S-pol measurements interpolated to a cartesian grid resolution of x=500m, y=150m, z=500m together with the dual Doppler synthesized winds interpolated to a grid resolution of x=y=1000m and z=500m.

• North-South cross-section of a developing cell at X=-13 km, 2100 UTC (see CAPPI image at 2100 UTC). The cross-section contains radar reflectivity, dual-Doppler diagnosed winds, ZDR (blue; contoured every 1 dB from 1 dB), and LDR (red; contoured from -22 dB every one dB; Max LDR = -20 dB). This particular growing cell was sampled by the Citation at approximately Z=5200 m (-2 to -3 C) along the axis of the cross-section. Note the column of ZDR extending above the height of the 0 C level (5 km), indicating the lofting of raindrops to sub-freezing temperatures. The enhancement in LDR just below to1 km above the0 C level suggests the beginnings of a glaciation process. The solid horizontal line indicates the approximate height of the Citation as it penetrated this cell (click here to see particle images from the Citation PMS 2DC probe for this cell).

• Similar to first cross-section (2100 UTC) but along X=-12.5 km. This cross-section is 500m east of the one above. Note the differences in vertical structure between the 2 cross-section.

• Similar to first cross-section (2100 UTC) but along X=2 km. This cell is slightly more mature than that of the first cross section (glaciation is indicated by LDR values; contours -23 dB and -21 dB).

• North-south cross section through intense, mature cell in the main convective line at 2100 UTC (X=6 km). Note the vertical extension and tilt of the ZDR column in the updraft near y = 37 km. An active freezing process is indicated by the elevated LDR values (-23,-21,-20,-19 dB contoured) located in the reflectivity core at y=39 km and between Z=4.5 and 6km. The extension of high LDR values into colder regions of the convection may indicate further freezing and/or a robust riming process.

• North-south cross section at X=-19 km through edge of cell complex to the west of the squall line at 2050 UTC (click here to see the CAPPI image at 2050 UTC).