Accession Number:

ADA219169

Title:

Turbulence Spectral Widths View Angle Independence as Observed by Doppler Radar

Descriptive Note:

Final rept.

Corporate Author:

COOPERATIVE INST FOR MESOSCALE METEOROLOGICAL STUDIES NORMAN OK

Personal Author(s):

Report Date:

1989-10-01

Pagination or Media Count:

57.0

Abstract:

As air traffic density increases, effective use of airspace must include consideration of weather. Accurate identification of turbulent volumes is of paramount importance to flight safety. The advent of Doppler radar has made it possible to observe wind motion in connective clouds. Over a number of years, research has lead to the spectral width standard deviation of the Doppler velocity measurements as an indicator of turbulence. In this paper we address the hypotheses that turbulence is essentially isotropic in convective systems, and therefore, observations of turbulence are independent of viewing angle. Radar observations made during the months of April, May, and June in 1980-1985 were scanned to locate storms amendable to analysis. A number of cases are presented in which a dual-Doppler network provided the essential data. Each case is in a different quadrant with respect to the Norman Doppler. Forty-four horizontal planes were studied from six different storms. The results of four of these storms are presented. Maximum reflectivity of these storms range from 51 to 58 dBZ. Altitudes include in this study range from near surface to 7 km. At these altitudes the maximum spectral width was 12 ms-1. For these cases, involving nearly 30,000 data points, 70 of the spectral width observations from CIM and NRO were within 1 ms-1 or less. These results indicate that the use of Doppler radar to detect turbulent regions within thunderstorms has a high probability of success, and the turbulent regions can be detected independent of the direction from which they are viewed. KR

Subject Categories:

  • Air Navigation and Guidance
  • Active and Passive Radar Detection and Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE