Optical Seeing at Sierra Negra

Carrasco, E.; Carramiñana, A.; Avilés, J. L.; Yam, O.

doi:10.1086/376396

Cited by 5 publications

(3 citation statements)

References 5 publications

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“…The seeing of Sierra Negra was monitored between 2000 and 2003 to quantify the potential of the site for optical astronomy. The site has a median seeing of 0.7 arcsec, consistent with that of a prime astronomical site (Carrasco et al 2003). The wind velocity at 200 mbar has been analysed using the National Oceanic and Atmospheric Administration (NOAA) National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis data base showing that Sierra Negra is comparable to the best observatory sites as Mauna Kea in terms of applying adaptive optics techniques such as slow wavefront corrugation correction (Carrasco, Avila & Carramiñana 2005), based on the premise that the global circulation of atmospheric winds at high altitude can be used as a criterion to establish the suitability of a site for the development of adaptive optics technique as the wind velocity at 200 mbar is strongly correlated to the average wavefront velocity allowing to compute the coherence time τ o (Sarazin & Tokovinin 2002).…”

Section: The Sierra Negra Sitesupporting

confidence: 64%

Weather at Sierra Negra: 7.3-yr statistics and a new method to estimate the temporal fraction of cloud cover

Carrasco

Carramiñana

Ávila³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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Sierra Negra, one of the highest peaks in central Mexico, is the site of the Large Millimeter Telescope. We describe the first results of a comprehensive analysis of the weather data measured in situ from 2000 October to 2008 February to be used as a reference for future activity in the site. We compare the data from two different stations at the summit considering the accuracy of both instruments. We analysed the diurnal, seasonal and annual cycles for all the parameters. The thermal stability is remarkably good, crucial for a good performance of the telescopes. From the solar radiation data, we developed a new method to estimate the fraction of time when the sky is clear of clouds. We show that our measurements are consistent with a warm standard atmosphere model. The conditions at the site are benign and stable given its altitude, showing that Sierra Negra is an extremely good site for millimeter and high‐energy observations.

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Section: The Sierra Negra Sitesupporting

confidence: 64%

Weather at Sierra Negra: 7.3-yr statistics and a new method to estimate the temporal fraction of cloud cover

Carrasco

Carramiñana

Ávila³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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“…We can then draw the conclusion that 200‐mbar wind speed is not a robust criterion for atmospheric columnar seeing prediction. This result is consistent with those obtained by other authors in shorter periods of time, like Carrasco et al (2003) for Sierra Negra.…”

Section: La Silla and Paranal Recordssupporting

confidence: 94%

High-altitude wind velocity at Oukaimeden observatory

Bounhir¹,

Benkhaldoun²,

Carrasco³

et al. 2009

Monthly Notices of the Royal Astronomical Society

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This paper aims at studying the wind at 200 mbar over the Moroccan observatory Oukaimeden, as high‐altitude winds have been adopted as a useful parameter for site characterization in terms of the suitability of a site for the development of some adaptive optics techniques. The data used come from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data base, which is widely acknowledged as being reliable. Statistical analyses of 200‐mbar wind speed since 1983 are performed. Comparison with some of the main observatory sites worldwide qualifies Oukaimeden as one of the best observatory sites in terms of 200‐mbar wind statistics. Our analysis of a record of seeing measurements during the years 2003 and 2004 concludes that while 200‐mbar wind speed can be used as a parameter for ranking astronomical sites in term of their suitability for adaptive optics, it cannot be used for the whole atmospheric seeing prediction. A comparison of monthly values of the seeing parameter at Oukaimeden, La Silla and Paranal demonstrates the high seeing quality of Oukaimeden, as the seeing values measured were lower than those of La Silla and Paranal for most of the time during the comparison period. Furthermore, a statistical analysis of atmospheric stratified seeing, wavefront coherence time and isoplanatic angle measured with a Multi‐Aperture Scintillation Sensor instrument over Paranal from 2004 to 2007 have been performed. We found good correlations between 200‐mbar wind velocity and levels 4, 5 and 6 seeing, wavefront coherence time and isoplanatic angle, with corresponding correlation coefficients of 0.74, 0.79, 0.70, 0.97 and 0.78.

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“…The seeing of Sierra Negra was monitored between 2000 and 2003 to quantify the potential of the site for optical astronomy. The site has a median seeing of 0.7", consistent with of a prime astronomical site (Carrasco et al 2003). The wind velocity at 200 mbar has been analyzed using the NOAA NCEP/NCAR reanalysis database showing that Sierra Negra is comparable to the best observatory sites as Mauna Kea in terms of applying adaptive optics techniques such as slow wavefront corrugation correction (Carrasco et al 2005), based on the premise that global circulation of atmospheric winds at high altitude can be used as a criterion to establish the suitability of a site for the development of adaptive optics technique as the wind velocity at 200 mbar is strongly correlated to the average wavefront velocity allowing to compute the coherence time τo (Sarazin & Tokovinin 2002).…”

Section: The Sierra Negra Sitesupporting

confidence: 58%

Weather at Sierra Negra: 7.3-year statistics and a new method to estimate the temporal fraction of cloud cover

Carrasco,

Carramiñana,

Avila

et al. 2009

Preprint

View full text Add to dashboard Cite

Sierra Negra, one of the highest peaks in central Mexico, is the site of the Large Millimeter Telescope. We describe the first results of a comprehensive analysis of the weather data measured in situ from October 2000 to February 2008 to be used as a reference for future activity in the site. We compare the data from two different stations at the summit considering the accuracy of both instruments. We analysed the diurnal, seasonal and annual cycles for all the parameters. The thermal stability is remarkably good, crucial for a good performance of the telescopes. From the solar radiation data we developed a new method to estimate the fraction of time when the sky is clear of clouds. We show that our measurements are consistent with a warm standard atmosphere model. The conditions at the site are benign and stable given its altitude, showing that Sierra Negra is a extremely good site for millimeter and high energy observations.

show abstract

Optical Seeing at Sierra Negra

Cited by 5 publications

References 5 publications

Weather at Sierra Negra: 7.3-yr statistics and a new method to estimate the temporal fraction of cloud cover

Weather at Sierra Negra: 7.3-yr statistics and a new method to estimate the temporal fraction of cloud cover

High-altitude wind velocity at Oukaimeden observatory

Weather at Sierra Negra: 7.3-year statistics and a new method to estimate the temporal fraction of cloud cover

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