TY  - JOUR
A1  - Strelnikov, B.
A1  - Rapp, M.
A1  - Fritts, D. C.
A1  - Wang, L.
T1  - Assessment of the Precision of Spectral Model Turbulence Analysis Techniques Using Direct Numerical Simulation Data
Y1  - 2022-02-17
VL  - 127
IS  - 4
JF  - Journal of Geophysical Research: Atmospheres
DO  - 10.1029/2021JD035516
PB  - 
N2  - The spectral model turbulence analysis technique is widely used to derive kinetic energy dissipation rates of turbulent structures (ɛ) from different in situ measurements in the Earth's atmosphere. The essence of this method is to fit a model spectrum to measured spectra of velocity or scalar quantity fluctuations and thereby to derive ɛ only from wavenumber dependence of turbulence spectra. Owing to the simplicity of spectral model of Heisenberg (1948), https://doi.org/10.1007/bf01668899 its application dominates in the literature. Making use of direct numerical simulations which are able to resolve turbulence spectra down to the smallest scales in dissipation range, we advance the spectral model technique by quantifying uncertainties for two spectral models, the Heisenberg (1948), https://doi.org/10.1007/bf01668899 and the Tatarskii (1971) model, depending on (a) resolution of measurements, (b) stage of turbulence evolution, (c) model used. We show that the model of Tatarskii (1971) can yield more accurate results and reveals higher sensitivity to the lowest ɛ‐values. This study shows that the spectral model technique can reliably derive ɛ if measured spectra only resolve half‐decade of power change within the viscous (viscous‐convective) subrange. In summary, we give some practical recommendations on how to derive the most precise and detailed turbulence dissipation field from in situ measurements depending on their quality. We also supply program code of the spectral models used in this study in Python, IDL, and Matlab.
N2  - Plain Language Summary: Turbulence plays a central role in most geophysical fluids, but our understanding of it remains limited. Atmospheric turbulence plays roles as diverse as dispersion of pollutants in the boundary layer to strong influences on the thermal and wind fields on global scales from the surface to above 100 km. It also is key to transports in, and the large‐scale circulation and structure of, Earth's oceans. Measurements quantifying turbulence intensities and their environments are key to understanding its many effects but remain challenging. In situ measurements of various quantities enable estimates of turbulence intensities but must be calibrated to be of optimal benefit. This study employs a direct numerical simulation of Kelvin‐Helmholtz instabilities that quantifies the associated turbulence dynamics exactly over the range of scales simulated to evaluate theoretical spectral forms enabling the best estimates of the known turbulence intensities.
N2  - Key Points: Accuracies of spectral model turbulence analysis techniques are evaluated using high‐resolution direct numerical simulation data. The Tatarskii model shows very accurate results if measured spectra resolve the viscous subrange for more than 2 decades. The Heisenberg model yields less accurate results that are almost independent of measurement resolution.
UR  - http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/9951
ER  -