The Multi-Scale Layering-Structure of Thermal Microscale Profiles
Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
Academic Editor: Lars Bengtsson
Water 2021, 13(21), 3042; https://doi.org/10.3390/w13213042
Received: 8 September 2021
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Revised: 19 October 2021
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Accepted: 19 October 2021
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Published: 1 November 2021
(This article belongs to the Special Issue Physical Processes in Lakes)
Thermal microstructure profiling is an established technique for investigating turbulent mixing and stratification in lakes and oceans. However, it provides only quasi-instantaneous, 1-D snapshots. Other approaches to measuring these phenomena exist, but each has logistic and/or quality weaknesses. Hence, turbulent mixing and stratification processes remain greatly under-sampled. This paper contributes to addressing this problem by presenting a novel analysis of thermal microstructure profiles, focusing on their multi-scale stratification structure. Profiles taken in two small lakes using a Self-Contained Automated Micro-Profiler (SCAMP) were analysed. For each profile, buoyancy frequency (N), Thorpe scales (LT), and the coefficient of vertical turbulent diffusivity (KZ) were determined. To characterize the multi-scale stratification, profiles of d2T/dz2 at a spectrum of scales were calculated and the number of turning points in them counted. Plotting these counts against the scale gave pseudo-spectra, which were characterized by the index D of their power law regression lines. Scale-dependent correlations of D with N, LT and KZ were found, and suggest that this approach may be useful for providing alternative estimates of the efficiency of turbulent mixing and measures of longer-term averages of KZ than current methods provide. Testing these potential uses will require comparison of field measurements of D with time-integrated KZ values and numerical simulations.
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Keywords:
fractal; lakes; mixing; multi-scale; stratification; turbulence
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MDPI and ACS Style
Folkard, A. The Multi-Scale Layering-Structure of Thermal Microscale Profiles. Water 2021, 13, 3042. https://doi.org/10.3390/w13213042
AMA Style
Folkard A. The Multi-Scale Layering-Structure of Thermal Microscale Profiles. Water. 2021; 13(21):3042. https://doi.org/10.3390/w13213042
Chicago/Turabian StyleFolkard, Andrew. 2021. "The Multi-Scale Layering-Structure of Thermal Microscale Profiles" Water 13, no. 21: 3042. https://doi.org/10.3390/w13213042
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