Air motion within Kelvin-Helmholtz billows determined from simultaneous Doppler radar and aircraft measurements
✍ Scribed by K. A. Browning; G. W. Bryant; J. R. Starr; D. N. Axford
- Book ID
- 104574374
- Publisher
- John Wiley and Sons
- Year
- 1973
- Tongue
- English
- Weight
- 900 KB
- Volume
- 99
- Category
- Article
- ISSN
- 0035-9009
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✦ Synopsis
Abstract
A new linked mode of operation has been used to obtain virtually simultaneous measurements by a fully instrumented aircraft and a ground‐based high power radar within a train of large amplitude Kelvin‐Helmholtz billows in the optically clear atmosphere. Both sets of data were analysed to show the detailed distribution of air motion and turbulence within the billows. The resulting pattern was consistent with a train of vortices each of which was characterized by a vertical wind shear of 6 m s^−1^ over 100 m, with downward motion of about 1 m s^−1^ on the downshear side and upward motion of about 1 m s^−1^ on the upshear side. Between the vortices the vertical shear decreased to almost half the maximum value. The most intense radar echoes occurred within inclined layers connecting the top of one region of maximum vorticity to the bottom of the next. The aircraft, which flew through the upper parts of the billows, encountered turbulence of up to moderate intensity as it penetrated the crests of the billows. Between successive penetrations of the billow crests the aircraft flew close to but just above the region of intense radar echo and encountered smooth air with a slowly varying vertical component of motion.