Characterization of the Martian Surface Layer

Abstract The authors have estimated the diurnal evolution of Monin–Obukhov length, friction velocity, temperature scale, surface heat flux, eddy-transfer coefficients for momentum and heat, and turbulent viscous dissipation rate on the Martian surface layer for a complete sol belonging to the Pathfinder mission. All these magnitudes have been derived from in situ wind and temperature measurements at around 1.3-m height and simulated ground temperature (from 0600 sol 25 to 0600 sol 26). Previously, neither values of turbulent viscous dissipation rate and eddy-transfer coefficients from in situ measurements for the Martian surface layer nor diurnal evolutions of all the previously mentioned turbulent parameters for the Pathfinder had been obtained. Monin–Obukhov similarity theory for stratified surface layers has been applied to obtain the results. The values assigned to the surface roughness and the applied parameterization of the interfacial sublayer will be discussed in detail with respect to the results’ sensitivity to them. The authors have found similarities concerning the order of magnitude and qualitative behavior of Monin–Obukhov length, friction velocity, and turbulent viscous dissipation rate on Earth and on Mars. However, quantities directly related to the lower Martian atmospheric density and thermal inertia, like temperature scale and hence surface heat flux, range over different orders of magnitude. Additionally, turbulent exchanges in the first few meters have been found to be just two orders of magnitude higher than the molecular ones, whereas on Earth around five orders of magnitude separate both mechanisms.

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Characterization of the Martian Convective Boundary Layer

Journal of the Atmospheric Sciences ◽

10.1175/2009jas3007.1 ◽

2009 ◽

Vol 66 (7) ◽

pp. 2044-2058 ◽

Cited By ~ 10

Author(s):

Germán Martínez ◽

Francisco Valero ◽

Luis Vázquez

Keyword(s):

Boundary Layer ◽

Surface Layer ◽

Standard Deviation ◽

Wind Speed ◽

Viscous Dissipation ◽

Mixed Layer ◽

Dissipation Rate ◽

Horizontal Wind

Abstract The authors have carried out an extensive characterization of the Martian mixed layer formed under convective conditions. The values of the mixed layer height, convective velocity scale, convective temperature scale, mean temperature standard deviation, mean horizontal and vertical velocity standard deviations, and mean turbulent viscous dissipation rate have been obtained during the strongest convective hours for the mixed layer. In addition, the existing database of the surface layer has been improved by recalculating some parameters (e.g., Monin–Obukhov length, friction velocity, or scale temperature) that had already been obtained in previous papers by other means and also by calculating new ones, such as the standard deviation of the vertical wind speed velocity, the turbulent viscous dissipation rate, and eddy transfer coefficients for momentum and heat. The Earth counterparts of all these magnitudes are also shown. In this paper, a comprehensive database concerning the whole convective planetary boundary layer on Mars is displayed, and a detailed terrestrial comparison is established. The inputs of this work are hourly in situ temperature, hourly in situ horizontal wind speed, and hourly simulated ground temperature for specific selected Sols of the Viking and Pathfinder landers. These data correspond to typical low and midlatitude northern summertime conditions, with weak prevailing winds. To handle this set of data, surface layer and mixed layer similarity theory have been used at the strongest convective hours. In addition, the inclusion of a parameterization of a molecular sublayer and prescribed values of the surface roughness has been considered.

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An Extremum Solution of the Monin–Obukhov Similarity Equations

Journal of the Atmospheric Sciences ◽

10.1175/2009jas3117.1 ◽

2010 ◽

Vol 67 (2) ◽

pp. 485-499 ◽

Cited By ~ 18

Author(s):

Jingfeng Wang ◽

Rafael L. Bras

Keyword(s):

Surface Layer ◽

Atmospheric Surface Layer ◽

Turbulent Transport ◽

Asymptotic Properties ◽

Field Measurements ◽

Surface Heat ◽

Heat Fluxes ◽

Obukhov Length ◽

Surface Heat Fluxes ◽

Momentum And Heat Fluxes

Abstract An extremum hypothesis of turbulent transport in the atmospheric surface layer is postulated. The hypothesis has led to a unique solution of Monin–Obukhov similarity equations in terms of simple expressions linking shear stress (momentum flux) and heat flux to mean wind shear and temperature gradient. The extremum solution is consistent with the well-known asymptotic properties of the surface layer. Validation of the extremum solution has been made by comparison to field measurements of momentum and heat fluxes. Furthermore, a modeling test of predicting surface heat fluxes using the results of this work is presented. A critical reexamination of the interpretation of the Obukhov length is given.

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Turbulent characteristics of a semiarid atmospheric surface layer from cup anemometers – effects of soil tillage treatment (Northern Spain)

Annales Geophysicae ◽

10.5194/angeo-21-2119-2003 ◽

2003 ◽

Vol 21 (10) ◽

pp. 2119-2131 ◽

Cited By ~ 8

Author(s):

S. Yahaya ◽

J. P. Frangi ◽

D. C. Richard

Keyword(s):

Surface Roughness ◽

Surface Layer ◽

Dissipation Rate ◽

Atmospheric Surface Layer ◽

Friction Velocity ◽

Roughness Length ◽

Energy Dissipation Rate ◽

Horizontal Wind ◽

Length Scale ◽

Integral Scale

Abstract. This paper deals with the characteristics of turbulent flow over two agricultural plots with various tillage treatments in a fallow, semiarid area (Central Aragon, Spain). The main dynamic characteristics of the Atmospheric Surface Layer (ASL) measured over the experimental site (friction velocity, roughness length, etc.), and energy budget, have been presented previously (Frangi and Richard, 2000). The current study is based on experimental measurements performed with cup anemometers located in the vicinity of the ground at 5 different levels (from 0.25 to 4 m) and sampled at 1 Hz. It reveals that the horizontal wind variance, the Eulerian integral scales, the frequency range of turbulence and the turbulent kinetic energy dissipation rate are affected by the surface roughness. In the vicinity of the ground surface, the horizontal wind variance logarithmically increases with height, directly in relation to the friction velocity and the roughness length scale. It was found that the time integral scale (and subsequently the length integral scale) increased with the surface roughness and decreased with the anemometer height. These variations imply some shifts in the meteorological spectral gap and some variations of the spectral peak length scale. The turbulent energy dissipation rate, affected by the soil roughness, shows a z-less stratification behaviour under stable conditions. In addition to the characterization of the studied ASL, this paper intends to show which turbulence characteristics, and under what conditions, are accessible through the cup anemometer.Key words. Meteorology and atmospheric dynamics (climatology, turbulence, instruments and techniques)

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VISCOUS DISSIPATION RATE

A-to-Z Guide to Thermodynamics Heat and Mass Transfer and Fluids Engineering ◽

10.1615/atoz.v.visdisrat ◽

2006 ◽

Vol v ◽

Keyword(s):

Viscous Dissipation ◽

Dissipation Rate

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Faculty Opinions recommendation of In Situ Structure of an Intact Lipopolysaccharide-Bound Bacterial Surface Layer.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.737130681.793569096 ◽

2019 ◽

Author(s):

Alexey Amunts

Keyword(s):

Surface Layer ◽

Bacterial Surface

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Description and Derived Climatologies of Automated In Situ Eddy-Dissipation-Rate Reports of Atmospheric Turbulence

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-13-0329.1 ◽

2014 ◽

Vol 53 (6) ◽

pp. 1416-1432 ◽

Cited By ~ 79

Author(s):

R. D. Sharman ◽

L. B. Cornman ◽

G. Meymaris ◽

J. Pearson ◽

T. Farrar

Keyword(s):

Atmospheric Turbulence ◽

Dissipation Rate ◽

Route Planning ◽

Federal Aviation Administration ◽

The United States ◽

Commercial Aircraft ◽

Upper Troposphere ◽

Obvious Benefit ◽

Turbulence Data

AbstractThe statistical properties of turbulence at upper levels in the atmosphere [upper troposphere and lower stratosphere (UTLS)] are still not well known, partly because of the lack of adequate routine observations. This is despite the obvious benefit that such observations would have for alerting aircraft of potentially hazardous conditions, either in real time or for route planning. To address this deficiency, a research project sponsored by the Federal Aviation Administration has developed a software package that automatically estimates and reports atmospheric turbulence intensity levels (as EDR ≡ ε1/3, where ε is the energy or eddy dissipation rate). The package has been tested and evaluated on commercial aircraft. The amount of turbulence data gathered from these in situ reports is unprecedented. As of January 2014, there are ~200 aircraft outfitted with this system, contributing to over 137 million archived records of EDR values through 2013, most of which were taken at cruise levels of commercial aircraft, that is, in the UTLS. In this paper, techniques used for estimating EDR are outlined and comparisons with pilot reports from the same or nearby aircraft are presented. These reports allow calibration of EDR in terms of traditionally reported intensity categories (“light,” “moderate,” or “severe”). The results of some statistical analyses of EDR values are also presented. These analyses are restricted to the United States for now, but, as this program is expanded to international carriers, such data will begin to become available over other areas of the globe.

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A New Experimental Technique for Measuring Surface Heat Transfer Coefficients Using Uncalibrated Liquid Crystals

10.1115/imece1999-1111 ◽

1999 ◽

Author(s):

Wayne N. O. Turnbull ◽

Patrick H. Oosthuizen

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Experimental Technique ◽

Surface Heat Flux ◽

Local Heat ◽

Surface Heat ◽

Phase Delay ◽

Transfer Coefficients ◽

Periodic Surface ◽

Heat Transfer Coefficients

Abstract A new experimental technique has been developed that permits the determination of local surface heat transfer coefficients on surfaces without requirement for calibration of the temperature-sensing device. The technique uses the phase delay that develops between the surface temperature response and an imposed periodic surface heat flux. This phase delay is dependent upon the thermophysical properties of the model, the heat flux driving frequency and the local heat transfer coefficient. It is not a function of magnitude of the local heat flux. Since only phase differences are being measured there is no requirement to calibrate the temperature sensor, in this instance a thermochromic liquid crystal. Application of a periodic surface heat flux to a flat plate resulted in a surface colour response that was a function of time. This response was captured using a standard colour CCD camera and the phase delay angles were determined using Fourier analysis. Only the 8 bit G component of the captured RGB signal was required, there being no need to determine a Hue value. From these experimentally obtained phase delay angles it was possible to determine heat transfer coefficients that compared well with those predicted using a standard correlation.

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