A reasonable estimate of a radar bird cross-section would be 10 cm2.
We then see that the average density of targets with a cross-section of 10 cm2 in the WSR-88D beam would be given by 2.8*Z or approximately 3*Z.
The table below indicates the type of information one can estimate from the value of dBZ obtained from the base reflectivity images. I have used the value of dBZ at 46 km (the range at which the present studies were made). A similar table could be set up for dBZ at other ranges.
WSR-88D dBZ | WSR-88D Z | Beam Density | Landing Density | Migration Traffic Rate | Landing Density |
250-950 m Birds/km3 | 250-950 m Birds/km2 | Rate 250-950 m Birds/km/hr | All Heights Birds/km2 | ||
dBZ | Z | 3.0*Z | 2.0*Z | 100*Z | 4.0*Z |
0 | 1 | 3 | 2 | 100 | 4 |
2.5 | 1.8 | 5.3 | 3.6 | 177.8 | 7.1 |
5 | 3.2 | 9.5 | 6.3 | 316.2 | 12.6 |
7.5 | 5.6 | 16.9 | 11.2 | 562.3 | 22.5 |
10 | 10.0 | 30.0 | 20.0 | 1000.0 | 40.0 |
12.5 | 17.8 | 53.3 | 35.6 | 1778.3 | 71.1 |
14 | 25.1 | 75.4 | 50.2 | 2511.9 | 100.5 |
15 | 31.6 | 94.9 | 63.2 | 3162.3 | 126.5 |
17.5 | 56.2 | 168.7 | 112.5 | 5623.4 | 224.9 |
20 | 100.0 | 300.0 | 200.0 | 10000.0 | 400.0 |
22.5 | 177.8 | 533.5 | 355.7 | 17782.8 | 711.3 |
25 | 316.2 | 948.7 | 632.5 | 31622.8 | 1264.9 |
27.5 | 562.3 | 1687.0 | 1124.7 | 56234.1 | 2249.4 |
30 | 1000.0 | 3000.0 | 2000.0 | 100000.0 | 4000.0 |
32.5 | 1778.3 | 5334.8 | 3556.6 | 177827.9 | 7113.1 |
35 | 3162.3 | 9486.8 | 6324.6 | 316227.8 | 12649.1 |
37.5 | 5623.4 | 16870.2 | 11246.8 | 562341.3 | 22493.7 |
40 | 10000.0 | 30000.0 | 20000.0 | 1000000.0 | 40000.0 |
This page is:
http://www.physics.brocku.ca/People/Faculty/Black/Galveston/nexradinterp.html
Last reviewed by:
awit@www.physics.brocku.ca
on 23-Jun-00 at 15:49
Brock University ©
2000