Radar Cross Sections for 990223

 

This page contains radar cross section images (gif format) of reflectivity and storm relative winds for the 990223 event, as well as some kinematic and reflectivity comparisons between EDOP and S-pol -TOGA. For additional information on radar comparisons for this event, check out Gerry Heymsfield's web page for 990223.


Ground-based Radar Cross Sections

Comparisons with ER2 Doppler Radar (EDOP - EDOP plots courtesy of Gerry Heymsfield at NASA GSFC)

Summary of Comparison of Ground-based with EDOP

Both the EDOP and ground-based radar analyses seem to capture the overall gross features with similar magnitudes along the flight leg. For example, the core near the center of the leg near 8-10 km (~40 km distance along the leg) are seen in both sets of plots. Also note the cell around 68 km along the flight track appear to be in reasonable agreement in terms of height and magnitude when comparing EDOP with the 21:00 UTC ground-based cross-section. This cell appears to have been collapsing, based on comparison with the 20:50 vol.

One complication in the comparison is that the 20:50 ground-based volume ends approximately 11 km along the flight track and the 21:00 UTC volume begins approximately 57 km along the flight track. Thus, only the observations at the beginning and the latter part of the flight track are well correlated in time between EDOP and the ground-based radars. For the cell near 40 km, the ground-based dual Doppler synthesis in the 20:50 UTC vol appears to have the peak ~1-1.5 km above and a bit farther south compared to the EDOP peak (note that EDOP shows a double peak structure at about 8.5 and10.5 m/s). The magnitudes of the updrafts in this core compare well at 20:50 but the ground-based synthesis at 21:00 UTC vol is at least1.5 m/s greater than EDOP (note in the ground-based analysis, the peak has shifted slightly farther north and downward at 21:00 UTC relative to 20:50 UTC). The differences in platform observations may be due to evolution of the cell in between the ground-based 20:50 and 21:00 UTC radar volumes.

Another complication is that the coarser resolution of the ground-based dual Doppler analysis smooths out the small-scale features sampled by EDOP (compare horizontal traces above). The effect of smearing in the ground based analysis compared to EDOP is evident and more quantitative comparisons will require smoothing the EDOP analyses to the resolution of the ground-based dual Doppler.

 

 

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