Meeting Abstract

S3-1.1  Friday, Jan. 4  Detection and Discrimination of Fauna in the Aerosphere Using Doppler Weather Surveillance Radar GAUTHREAUX, S.A.*; BELSER, C.G.; Clemson University; Clemson University

One of the major challenges of understanding daily and seasonal movements of airborne fauna is to reliable detect and discriminate among different taxa. For the past 15 years, we have used Doppler weather surveillance radar (WSR-88D) to detect and monitor movements of airborne fauna (notably birds, bats and insects). Recently we have used Level II radar velocity data (pulse volume resolution of 1 x 250 m) and winds aloft data to determine the statistical distributions of the maximum inbound and outbound ground speeds of airborne fauna. Because migrating birds and bats have mean radial velocities greater than most insects and randomly foraging birds and bats, these data can be used to detect and discriminate returns from targets aloft. Polarimetric spectral analysis and other polarimetric variables from dual polarization radar can also be used to discriminate airborne fauna. Differential reflectivity, backscatter differential phase, and correlation coefficients between orthogonally polarized returns are most useful for detecting and discriminating targets aloft. For insects the backscatter differential phase is sizable (ranging between 5 and 40), differential reflectivity can be as high as 10 dB, and both reflectivity and differential reflectivity are strongly azimuth dependent revealing a high degree of common alignment. For birds, differential phase is larger (sometimes over 100) and differential reflectivity is small (ranging between -1 and 3 dB). Upcoming changes to the WSR-88D (decrease in beam width, increased reflectivity resolution, and dual polarization) will greatly enhance the utility of weather surveillance radar for investigating flight behavior and ecology of fauna in the aerosphere.