Optical turbulence and outer scales above Dome C in Antarctica

Trinquet, H.; Agabi, A.; Vernin, J.; Azouit, M.; Aristidi, Éric; Fossat, E.

doi:10.1117/12.787858

Cited by 17 publications

(35 citation statements)

References 5 publications

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“…The ability of the model to forecast the evolution of the atmosphere and the optical turbulence above the Antarctic Plateau has been extensively discussed in a previous paper by our team . In that paper all the 15 winter nights, for which measurements of the C 2 N are available (Trinquet et al 2008) above Dome C, have been simulated with Meso-NH. The main conclusion of was that Meso-NH was able to reconstruct the optical turbulence in a region with extreme meteorological conditions such as Dome C. However a mono-domain configura-⋆ E-mail: lascaux@arcetri.astro.it; masciadri@arcetri.astro.it tion with low resolution (100 km) is not suitable to provide optical turbulence features well correlated to measurements while a grid-nesting configuration done with three domains (horizontal resolutions of 25 km, 10 km and 1 km) does it.…”

Section: Introductionmentioning

confidence: 99%

Mesoscale optical turbulence simulations at Dome C: refinements

Lascaux¹,

Masciadri²,

Hagelin³

2010

Monthly Notices of the Royal Astronomical Society

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In a recent paper the authors presented an extended study aiming at simulating the classical meteorological parameters and the optical turbulence at Dome C during the winter with the atmospherical mesoscale model Meso-NH. A statistical analysis has been presented and the conclusions of that paper have been very promising. Wind speed and temperature fields revealed to be very well reconstructed by the Meso-NH model with better performances than what has been achieved with the European Centre for Medium-Range Weather Forecast (ECMWF) global model, especially near the surface. All results revealed to be resolution-dependent and it has been proved that a grid-nesting configuration (3 domains) with a high horizontal resolution (1km) for the innermost domain is necessary to reconstruct all the optical turbulence features with a good correlation to measurements. High resolution simulations provided an averaged surface layer thickness just ~14 m higher than what is estimated by measurements, the seeing in the free atmosphere showed a dispersion from the observed one of just a few hundredths of an arcsecond (~0.05"). The unique limitation of the previous study was that the optical turbulence in the surface layer appeared overestimated by the model in both low and high resolution modes. In this study we present the results obtained with an improved numerical configuration. The same 15 nights have been simulated, and we show that the model results now match almost perfectly the observations in all their features: the surface thickness, the seeing in the free atmosphere as well as in the surface layer. This result permits us to investigate now other antarctic sites using a robust numerical model well adapted to the extreme polar conditions (Meso-NH).Comment: 5 pages, 4 figures, accepted for publication in MNRA

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Section: Introductionmentioning

confidence: 99%

Mesoscale optical turbulence simulations at Dome C: refinements

Lascaux¹,

Masciadri²,

Hagelin³

2010

Monthly Notices of the Royal Astronomical Society

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“…The very low infrared background and atmospheric watervapour content of Antarctic plateau sites such as Dome C enable a telescope based there to achieve the sensitivity (at some wavelengths) of a telescope over three times that diameter located elsewhere (Lawrence 2004;Walden et al 2005;Tomasi et al 2006). The atmospheric turbulence above Dome C is also 2 to 3 times lower than that at even the best temperate sites (Lawrence et al 2004;Agabi et al 2006;Trinquet et al 2008). An optical/infrared telescope at Dome C would thus be supremely powerful for its size, enjoying not only a substantial advantage in both sensitivity and photometric precision, but also having a wide-field, high-resolution, high-cadence imaging capability otherwise achievable only from space Mosser & Aristidi 2007).…”

Section: Introductionmentioning

confidence: 91%

“…• excellent free-atmospheric seeing (Lawrence et al 2004;Agabi et al 2006;Trinquet et al 2008), • low turbulent boundary layer height (Lawrence et al 2004;Agabi et al 2006;Trinquet et al 2008), • wide isoplanatic angle and long coherence time (Lawrence et al 2004;Agabi et al 2006;Trinquet et al 2008), • low atmospheric scintillation ),…”

Section: Dome C Site Conditionsmentioning

confidence: 99%

The Science Case for PILOT I: Summary and Overview

Lawrence

Ashley

Bailey

et al. 2009

Publ. – Astron. Soc. Aust

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PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/ infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science

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“…Bufton et al [18] measured turbulence in the troposphere by thermal sensor, then reduced its weight to less than 3 kg, and operated in only two scale ranges from a temperature difference noise level of 0.004 to a maximum temperature difference of 0.676 K [19], [20]. Azout et al [21] presented in situ technique to measure the microstructure of the temperature field in atmosphere, which gained the structure function of refractive index along with atmospheric pressure, temperature, humidity, and wind speed. This cross-calibrated technique gave a higher spatiotemporal resolution than before.…”

Section: Introductionmentioning

confidence: 99%

Turbulent Structure Function Analysis Using Wireless Micro-Thermometer

Shao¹,

Qin

Liu

et al. 2020

IEEE Access

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Most of the application scenarios of techniques related to electromagnetic wave transmission of photoelectric system are located in the earth's atmosphere or through the atmospheric path. The electromagnetic wave will change state through the atmosphere when encounters the inhomogeneities of refractive index caused by turbulence. Optical turbulence causes degradation of beam quality and energy to laser transmission, and brings image deterioration to astronomical observation. The refractive index structure coefficient is an important parameter describing the turbulence strength. For visible and near infrared band, the refractive index structure coefficient mainly depends on temperature structure coefficient. Using the theory of Wheatstone bridge, the micro-thermometer is designed and self-developed. To avoid interference from human and buildings, the wireless control for the micro-thermometer is realized based on CC1100. The observation of turbulence strength of representative test point, for more than one month, is implemented at Yangmeikeng near the South China Sea. Compared to ultrasonic anemometer, there is a sensitive lower measurement limit of micro-thermometer whose effective refractive index structure coefficient of system noise is less than 18 10  m-2/3. There is obvious 'Sombrero' structure diurnal variation of turbulence near South China Sea, whose strength is mainly brought out by buoyancy heat bubble in day, and by wind shear at night. Monin-Obukhov length is positive at night and negative in day, and the scaling exponent is near-5/3 for temperature power spectrum, which is similar to wind power spectrum except for periods when wind from inland. The diurnal variation and scaling exponent of power spectrum analysis indicate that the measurement range and the sample rate of micro-thermometer are enough to response the turbulence measurement encountered in most laser transmission and astronomical observation fields. The turbulence characteristics information gained from micro-thermometer measurement data analysis brings good reference to optimal design and operation for photoelectric system.

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Optical turbulence and outer scales above Dome C in Antarctica

Cited by 17 publications

References 5 publications

Mesoscale optical turbulence simulations at Dome C: refinements

Mesoscale optical turbulence simulations at Dome C: refinements

The Science Case for PILOT I: Summary and Overview

Turbulent Structure Function Analysis Using Wireless Micro-Thermometer

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