Turbulence velocity profiling for high sensitivity and vertical-resolution atmospheric characterization with Stereo-SCIDAR

Osborn, James; Butterley, T.; Townson, Matthew J.; Reeves, Andrew; Morris, Tim; Wilson, Richard W.

doi:10.1093/mnras/stw2685

Cited by 22 publications

(23 citation statements)

References 30 publications

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“…This comparison allows us to easily validate the forecasts. We have previously shown that the wind velocity profile from these models correlates well with the turbulence velocity profiles from the stereo-SCIDAR, despite the low spatial resolution (Osborn et al 2017), demonstrating that the model can be reliable used to forecast turbulence velocity. However, in order to fulfil the potential of the model we must also be able to forecast the strength as well as the velocity of the optical turbulence.…”

Section: Introductionmentioning

confidence: 85%

“…General circulation models (GCM) have been used to provide wind velocity profiles for previous astronomical studies (for example, Hagelin et al 2010;Osborn et al 2017). They have also been used as the input for mesoscale turbulence forecast models (for example, Giordano et al 2013;Masciadri et al 2017).…”

Section: General Circulation Modelsmentioning

confidence: 99%

“…For example, a velocity shear within a resolution element may not be seen by the model. It is common in stereo-SCIDAR data to see wind shear of up to 20 degrees within a single turbulent layer of less then a few hundred metres in depth (Osborn et al 2017). This might not be reproduced by the GCM.…”

Section: Median Profilesmentioning

confidence: 99%

“…Adaptive Optics (AO) systems must be implemented in order to recover the spatial resolution by compensating for the phase aberration induced by the turbulence. In the current era of large 8-10 m class telescopes and the future 40 m extremely large telescopes it is of critical importance to have thorough knowledge of the vertical structure of the turbulence strength (for example, Osborn et al 2016;Gendron et al 2014;Basden et al 2010;Vidal et al 2010;Neichel et al 2008) and velocity (for example, Osborn et al 2017;Kulcsár et al 2006;Paschall & Anderson 1993. In addition, if this knowledge can be forecast in advance then this enables some significant benefits in operational efficiency of the modern observatory and, critically, will enable the most sensitive of observations to be scheduled, and executed in the optimum conditions (Masciadri et al 2013b).…”

Section: Introductionmentioning

confidence: 99%

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Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal

Osborn

Sarazin

2018

Monthly Notices of the Royal Astronomical Society

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In addition to astro-meteorological parameters, such as seeing, coherence time and isoplanatic angle, the vertical profile of the Earth's atmospheric turbulence strength and velocity is important for instrument design, performance validation and monitoring, and observation scheduling and management. Here we compare these astro-meteorological parameters as well as the vertical profile itself from a forecast model based on a General Circulation Model from the European Centre for Median range Weather Forecasts and the stereo-SCIDAR, a highsensitivity turbulence profiling instrument in regular operation at Paranal, Chile. The model is fast to process as no spatial nesting or data manipulation is performed. This speed enables the model to be reactive based on the most up to date forecasts. We find that the model is statistically consistent with measurements from stereo-SCIDAR. The correlation of the median turbulence profile from the model and the measurement is 0.98. We also find that the distributions of astro-meteorological parameters are consistent. We compare contemporaneous measurements and show that the free atmosphere seeing, isoplanatic angle and coherence time have correlation values of 0.64, 0.40 and 0.63 respectively. We show and compare the profile sequences from a large number of trial nights. We see that the model is able to forecast the evolution of dominating features. In addition to smart scheduling, ensuring that the most sensitive astronomical observations are scheduled for the optimum time, this model could enable remote site characterisation using a large archive of weather forecasts and could be used to optimise the performance of wide-field AO system.

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Section: Introductionmentioning

confidence: 85%

Section: General Circulation Modelsmentioning

confidence: 99%

Section: Median Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal

Osborn

Sarazin

2018

Monthly Notices of the Royal Astronomical Society

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“…Huge efforts are dedicated to the development of modern AO systems in new generation telescopes. As telescopes become larger, the performance of AO systems becomes more sensitive to variations of the vertical distribution of the op-E-mail: remy@fata.unam.mx tical turbulence strength C 2 N (h) (Osborn et al 2017;Neichel et al 2009;Basden et al 2010;Vidal et al 2010;Masciadri et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous generalized and low-layer SCIDAR turbulence profiles at san pedro mártir observatory

Ávila

Valdés-Hernández

Sánchez

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present optical turbulence profiles obtained with a Generalized SCIDAR (G-SCIDAR) and a Low Layer SCIDAR (LOLAS) at the Observatorio Astronómico Nacional in San Pedro Mártir (OAN-SPM), Baja California, Mexico, during three observing campaigns in 2013, 2014 and 2015. The G-SCIDAR delivers profiles with moderate altitude-resolution (a few hundred meters) along the entire turbulent section of the atmosphere, while the LOLAS gives high altitude-resolution (on the order of tens of meters) but only within the first few hundred meters. Simultaneous measurements were obtained on 2014 and allowed us to characterize in detail the combined effect of the local orography and wind direction on the turbulence distribution close to the ground. At the beginning of several nights, the LOLAS profiles show that turbulence peaks between 25 and 50 m above the ground, not at ground level as was expected. The G-SCIDAR profiles exhibit a peak within the first kilometer. In 55% and 36% of the nights stable layers are detected between 10 and 15 km and at 3 km, respectively. This distribution is consistent with the results obtained with a G-SCIDAR in 1997 and 2000 observing campaigns. Statistics computed with the 7891 profiles that have been measured at the OAN-SPM with a G-SCIDAR in 1997, 2000and 2015 campaigns are presented. The seeing values calculated with each of those profiles have a median of 0.79, first and third quartiles of 0.51 and 1.08 arcsec, which are in close agreement with other long term seeing monitoring performed at the OAN-SPM.

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Daytime optical turbulence profiling with a profiler of the differential solar limb

Song

Cai

Liu

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Atmospheric turbulence reduces the image quality and resolution of ground-based optical telescopes. Future large solar telescopes (e.g. the CGST, China Giant Solar Telescope) should be equipped with adaptive optics (AO) systems. The design of AO systems is associated with atmospheric optical turbulence parameters, especially the profile of the refractive index structure $C_{n}^{2}(h)$. With the solar differential image motion monitor (S-DIMM) and the profiler of the moon limb (PML), a simplified version of a PML, termed a profiler of the differential solar limb (PDSL), was built in order to determine the daytime $C_{n}^{2}(h)$ and other atmospheric turbulence parameters. A PDSL with differential solar limb fluctuations was used to determine the turbulence profiling, and the extended solar limb extends the range of separation angles for a higher resolution of the height profile. The PDSL structure and its performance are described. In addition, numerical simulations were conducted to verify the effectiveness of the method. As revealed from the simulation results, the layered integral coefficient matrix is capable of solving the discretization error and enhancing the inversion accuracy of the turbulence contour. The first test results at Mt Wumingshan (a candidate site for the CGST) are presented.

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Turbulence velocity profiling for high sensitivity and vertical-resolution atmospheric characterization with Stereo-SCIDAR

Cited by 22 publications

References 30 publications

Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal

Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal

Simultaneous generalized and low-layer SCIDAR turbulence profiles at san pedro mártir observatory

Daytime optical turbulence profiling with a profiler of the differential solar limb

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