Accession Number : AD0781847

Title :   Convective Activity Observed by FM-CW Radar.

Descriptive Note : Research and Development, Jul 71-Dec 73,


Personal Author(s) : Noonkester,V. R.

Report Date : 10 MAY 1974

Pagination or Media Count : 72

Abstract : 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)

Descriptors :   *Convection(Atmospheric), *Radar reflections, Wind, Continuous wave radar, Frequency modulation, Atmospheric temperature, Humidity, Turbulence, Radiosondes

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE