Convective Activity Observed by FM-CW Radar.
Research and Development, Jul 71-Dec 73,
NAVAL ELECTRONICS LAB CENTER SAN DIEGO CALIF
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Data taken in San Diego by the fixed and mobile FM-CW frequency-modulated, continuous-wave radars reveal characteristic echo structures created by forced and free convection. Echoes produced by forced convection are not structured and are observed over rough terrain when the surface wind speed is above average and the vertical lapse rate of temperature is nearly unstabily stratified. Echoes produced by free convection C-echoes have been observed simultaneously at the coast and 5.6 km inland. C-echoes are structured and observed when the surface is strongly heated by the sun. C-echoes extended above the tops of surface-based superadiabatic layers which were always present when C-echoes were observed. The presence of the superadiabatic layer at the coast during a westerly wind is unexplained. At 5.6 km inland the C-echoes often appear like inverted Us or Vs plumes whose tops penetrate upward to greater heights as surface heating continues. Dissipation occurs in the late afternoon. The plumes sometimes occurred in well-defined sequences. Modified author abstract