资源环境科技发展态势分析平台

One-second wind data on the West Florida Shelf were used to examine turbulent scales from large eddies to small eddies in the atmospheric surface layer within a frequency band from 0.02 to 0.3Hz (periods from 1min to 3s). Data were collected at two at-sea locations spanning 6.5months. Three events in three wind ranges were examined in exploring the one-dimensional turbulent power spectra: >14m/s, wind range I; those between 10 and 14m/s, wind range II; and those between 5 and 10m/s, wind range III. Events consisted of ensembles of abutting 30-min subsets spanning 5.5 to 23hr. The mean vector wind time scale of T-0=30min was found to be reasonable for the West Florida Shelf region. The first wind range provided the best results, more or less in line with a Kolmogorov -5/3 power law whose mean vector wind speed over 21 subsets (10.5hr) was nearly 15m/s. The one-dimensional turbulent power spectra provided an estimate of the dissipation rate (epsilon) from which other turbulent quantities could be computed: u*, , and C-d (the frictional velocity, the surface stress, and the drag coefficient, respectively). The salient point here is that these quantities were larger than those from previous observational studies. Where the power law was not operant intrinsic turbulent spatial scales ranged from 1 to 0.1m and provide evidence of anisotropy for frequencies greater than 0.1Hz.

Plain Language Summary Wind data sampled at 1Hz were collected at two at-sea locations on the West Florida Shelf where data common to both moorings span roughly 6.5months. We showed that a mean vector wind time scale of T-0=30min is reasonable for the West Florida Shelf domain. Three wind ranges were examined from which the one-dimensional turbulent power spectra allowed estimates of turbulent parameters crucial in developing momentum flux algorithms used in numerical models of both the atmosphere and the ocean. Turbulence parameters were found to be larger than expected suggesting that improving flux algorithms should be a high priority.