Horizontal velocity structure functions in the upper troposphere and lower stratosphere 1. Observations
2001 (English)In: Journal of Geophysical Research-Atmospheres, ISSN 0747-7309, Vol. 106, no D10, 10223-10232 p.Article in journal (Refereed) Published
We compute horizontal velocity structure functions using quasiglobal data accumulated by specially equipped commercial aircraft on 7630 flights from August 1994 to December 1997. Using the ozone concentration measurements, we classify the results as tropospheric or stratospheric. We further divide the results into four absolute latitude bands. For separation distance r between 10 and 100 km, the lower stratospheric diagonal third-order structure functions are proportional to negative r. This implies a downscale energy cascade, and we estimate the mean energy dissipation rate to be (E) approximate to 6 x 10(-5) m(2) s(-3). For r between 300 and 1500 km a positive r(3) dependence was visible for the polar stratospheric data. This may be the result of a two-dimensional (2D) turbulence downscale enstrophy cascade, and we estimate the average enstrophy flux to be IIomega approximate to 2 x 10(-15) s(-3) and the energy spectral constant to be K approximate to 2. The negative sign of these third-order functions at mesoscales in both the upper troposphere and lower stratosphere provide no support for an inverse energy cascade 2D turbulence. At scales above similar to 100 km, the second-order structure functions increase with latitude in the troposphere and decrease with latitude in the stratosphere. The off-diagonal third-order functions in the stratosphere show a remarkably clean negative r(2) dependency from 10 to 1000 km in scale.
Place, publisher, year, edition, pages
2001. Vol. 106, no D10, 10223-10232 p.
mozaic airborne program, wave-number spectra, 2-dimensional turbulence, stratified turbulence, radar observations, temperature, variability, atmosphere, aircraft, range
IdentifiersURN: urn:nbn:se:kth:diva-20647ISI: 000168839900007OAI: oai:DiVA.org:kth-20647DiVA: diva2:339343
QC 201005252010-08-102010-08-10Bibliographically approved