Accession Number : ADA138579

Title :   Test and Evaluation of the Radar Thunderstorm Turbulence Detection System.

Descriptive Note : Interim rept. Mar 80-Jun 81 on Phase 1,


Personal Author(s) : Lewis,W ; Oliver,R G ; DeLaMarche,A ; Lee,T Y

PDF Url : ADA138579

Report Date : Jul 1982

Pagination or Media Count : 28

Abstract : A thunderstorm turbulence detection test bed was developed at the Federal Aviation Administration (FAA) Technical Center by the Massachusetts Institute of Technology, Lincoln Laboratory. This consists of a system to measure and process Doppler radar parameters, and an FAA aircraft instrumented to measure turbulence concurrently with the radar observations. The test bed is being used to investigate the relationship between radar-and aircraft-measured turbulence. Radar measurements of the Doppler spectrum width and aircraft measurements of airspeed fluctuations and center-of-gravity normal accelerations were converted to the cube root of epsilon (cube root of the turbulence dissipation factor) for comparison. Several data collections were made during the summer of 1980. Results of data analysis showed that the major turbulence sequences experienced by the aircraft were essentially reflected by the radar. However, Linear correlation coefficients between radar and aircraft the the cube root of epsilon were only about 0.5. The low correlations are considered to be due to differences in response to turbulence by the two measuring systems, deficiencies in the radar processing, and radar data interpolation errors between the 80-second radar scans. In a more practical analysis, radar-measured turbulence, classified into ranges of light, moderate, and severe turbulence, showed a potentially useful relationship to aircraft turbulence. The predictive value was enhanced by consideration of radar reflectivity factor as a screening variable.

Descriptors :   *Turbulence, *Radar reflections, Detection, Thunderstorms, Doppler effect, Velocity, Research aircraft, Acceleration, Measurement, Airport radar systems, Statistical analysis, Correlation

Subject Categories : Meteorology
      Active & Passive Radar Detection & Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE