Constraining the inertial dissipation method using the vertical velocity variance

Abstract

[1] The inertial dissipation method (IDM) is commonly used to measure turbulent fluxes over the ocean. It has the advantage over more direct methods in that it depends on the turbulent fluctuations only in the high frequencies of the so-called inertial subrange. These frequencies are above those of typical ship motions and are considered to be relatively unaffected by flow distortion. However, a drawback in applying the method is that the problem is underdetermined: estimation of the fluxes requires knowledge of the Obukhov length L, which is itself a function of the fluxes. The problem is typically solved by iteration, using an initial L estimated from bulk formulae. This introduces a possible dependency on the initial bulk estimate along with problems of convergence. Recently, several authors have proposed improvements to the basic algorithm. For instance, Dupuis et al. [1997] proposed a parameterization of the ''imbalance term'' in the budget of turbulent kinetic energy (TKE). We explore an alternative approach to the problem. In order to constrain the equations resulting from the IDM we use the vertical velocity variance, s w, measured from the research vessel L'Atalante and an ASIS buoy, both deployed during the 1998 FETCH experiment. These data are compared to several parameterizations of s w on stability derived in experiments. For unstable cases, the data are found to be well described by the Panofsky and Dutton [1984] parameterization, although the scatter of the data is higher for swell conditions than for pure wind sea, indicating a likely sea state effect. Using measured values of s w along with this parameterization, the inertial dissipation problem is fully specified. The convergence of the method is satisfactory, and it offers u * estimates independent of bulk formulae.

Turbulent air‐sea fluxes in the Gulf of Guinea during the AMMA experiment

“…We use temporal structure function of order three to compute turbulent dissipation rate using Kolmogorov's [1941] -4/5 law, which is analyzed as a complement to the ID method. We also analyze several new arguments showing the relevance of À0.5 z L À1 imbalance as proposed by Dupuis et al [1997] during SOFIA-ASTEX and the ''Structures des Echanges Mer-Atmosphère Prospections des Hétérogénéités Océaniques, leur Répartition, projet d'Expérience'' (SEMAPHORE) experiments, which complements those suggested by Dardier et al [2003] during the FETCH experiment. For the EC method, the importance of a good time synchronization of the different variables used to get fluxes is pointed out.…”

“…Improved flux measurement methods, such as the inertial dissipation (ID) or the eddy correlation (EC) methods have been developed at Centre d'Etude des Environnements Terrestre et Planétaires (CETP) using data collected since the “Surface de l'Océan Flux et Interactions avec l'Atmosphère/Atlantic Structure Transition Experiment” (SOFIA/ASTEX) in 1992 [ Weill et al , 1995]. These methods have been successfully applied during several experiments, as referenced in papers by Dupuis et al [1995, 1997], H. Dupuis et al (Heat fluxes by the inertial dissipation method during FETCH, paper presented at Symposium on Air‐Sea Interface, University of New South Wales, Sydney, New South Wales, Australia, 11–15 January 1999), Pedreros et al [2003], Dardier et al [2003], and Brut et al [2005].…”

Photometric characterization of Lucideon and Avian Technologies color standards including application for calibration of the Mastcam-Z instrument on the Mars 2020 rover

“…Our data alone are too sparse for a full BRDF characterization as was done in Ref. 11, but this will be future work at a more restricted set of wavelengths. Additional measurements will be taken at the Bloomsberg University Goniometer, and the data will be integrated into a scattering model covering all geometries.…”

The FETCH experiment: An overview

“…In an other study by Dardier et al [2003], an alternative method to derive the friction velocity is proposed corresponding to a modification of the classical inertio‐dissipative method. Based on motion corrected vertical velocity standard deviations, it associates the Panofsky [1972] parameterization with the Turbulent Kinetic Energy (TKE) equation from which a friction velocity is estimated.…”