Three-dimensional wind measurements in the optically clear planetary boundary layer with dual-Doppler radar


  • R. A. Kropfli,

  • P. H. Hildebrand


Radar-derived three-dimensional wind fields were obtained near the Boulder Atmospheric Observatory tower during a planetary boundary layer (PBL) experiment called Phoenix in September 1978. A pair of closely spaced (12.3 km) Doppler radars observed the entire depth of the daytime PBL (˜2 km) over an area of ˜100 km2, with hundreds of velocity samples per km3, a radar resolution volume size of 150 m in all dimensions at the tower, and volume scan intervals of 50–180 s. The radar measurements obtained are compared with in situ measurements on aircraft, on the instrumented tower, and with other surface wind data. Preliminary results indicate that these data resolve wavelengths as small as 600 m and that the measurements are repeatable at each grid point to within 0.3 m/s. The radar-derived wind fluctuations agreed with anemometer data on the tower to within 0.5 m/s and with data from an aircraft-borne anemometer to within 1.0 m/s.