Radar observations of stable boundary layer during CASES'99

In October 1999, the University of Massachusetts Microwave Remote Sensing Laboratory deployed a high-resolution, S-band FMCW radar profiler and a volume-imaging 915 MHz radar to study the structure and dynamics of the nocturnal boundary layer during CASES'99. Here, the FMCW radar produced real-time imagery of a variety boundary layer features including Kelvin-Helmholtz instabilities, gravity waves, and clear-air convection. Real-time images were used to guide research aircraft to sample these features with on-board instrumentation. In addition to clear-air (Bragg) returns, the S-band radar often observed significant scatter from insects and migrating birds. The distribution of insect scatter appears to reveal additional boundary layer structure not otherwise detectable at S-band. Observations during selected intensive observation periods are compared to simultaneous in-situ and UHF radar measurements of the same atmospheric volume.