Further Discussion of the Dynamical Processes That Contribute to the Spectrum of Mesoscale Atmospheric Motions,
Abstract
In recent years much progress has been made in determining the spectrum of mesoscale atmospheric motions. The frequency spectra of vertical and horizontal velocities have been determined in the free atmosphere by means of the nearly continuous measurement of radial velocity by wind-profiling Doppler radar. In addition, wind measurements by commercial aircraft collected during the NASA Global Atmospheric Sampling Program (GASP) have been analyzed to yield wavenumber spectra in the upper tropophere and lower atmosphere that cover scales ranging from a few km to 10,000 km. This paper considered the dynamical processes that may be responsible for the observed mesoscale atmospheric wind spectra. The issue of whether the observed spectrum of horizontal velocity is due primarily to waves or turbulence by comparing the dependence of the observed horizontal velocity spectra on wind speed with the Doppler shifting effect anticipated for a model wave spectrum and for a model turbulence spectrum. The results show that the observed spectra do not follow either the turbulence model or the wave model very closely. However, the turbulence model seems to fit the observations more closely than does the wave model.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 23, 1988
- Accession Number
- ADA195277
Entities
People
- G. D. Nastrom
- K. S. Gage
Organizations
- Control Data Corporation