Accession Number : ADA188390

Title :   Research and Development to Acquire and Reduce Melting Layer Cloud Physics and Evaluate a Prototype M-Meter.

Descriptive Note : Final rept. Dec 85-May 87,

Corporate Author : COLORADO INTERNATIONAL CORP BOULDER

Personal Author(s) : Davis, Larry G ; Lawson, R P

PDF Url : ADA188390

Report Date : May 1987

Pagination or Media Count : 79

Abstract : A research aircraft was equipped with imaging probes and an airborne KA Band radar, along with the standard compliment of cloud physics instrumentation, and was flown in the melting layer of stratiform clouds. Heavy precipitation events during the research period were scarce, and the data presented here reflect analysis of precipitation from storms of light to occasionally moderate intensity. The dearth of strong precipitation events did not favor the formation of a deep melting layer with strong microwave attenuation characteristics, and this inhibited attempts to correlate observed attenuation of microwave signals with in situ cloud physics measurements. Results of comparisons between the airborne KA-band radar and the PMs imaging probes show a considerable variation in the echo returns as well as the cloud hydrometeor characteristics. Thus the microwave scattering properties through the melting layer are also highly variable. The observed vertical profiles of the evolution of precipitation particles shows that rapid aggregation occurs near the -2 C level, and that some large aggregates fall to temperatures as warm as +4 C before melting. Thus there is a region of approximately 800 m where partially melted aggregates can substantially influence the propagation of microwaves. Keywords: Cloud physics; Melting layer; Microwave attenuation; Brightband; Airborne radar; Ka band radar; Aggregation; Precipitation; Airborne instrumentation.

Descriptors :   *RADAR REFLECTIONS, *METEOROLOGICAL INSTRUMENTS, *RADAR EQUIPMENT, AIRBORNE, ATTENUATION, CLOUD PHYSICS, CLOUDS, INSTRUMENTATION, KA BAND, LAYERS, LIGHT, MEASUREMENT, MELTING, PARTICLES, PROFILES, PROPAGATION, RADAR, RESEARCH AIRCRAFT, SIGNALS, STORMS, STRATUS CLOUDS, VERTICAL ORIENTATION, ELECTROMAGNETIC SCATTERING

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE