The Optical/Infrared Astronomical Quality of High Atacama Sites. II. Infrared Characteristics

Giovanelli, Riccardo; Darling, Jeremy; Henderson, Christine; Hoffman, William F.; Barry, D. C.; Cordes, James; Eikenberry, S. S.; Gull, G. E.; Keller, L. D.; Smith, John David; Stacey, G. J.

doi:10.1086/322136

Cited by 53 publications

(45 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… a The quartile values found at the Mauna Kea [ Hogg , 1992] and Atacama [ Lane , 1998; Giovanelli et al , 2001] observatories are given for comparison. The monthly mean values of W measured at the Kitt Peak National Observatory (USA) were found by Wallace and Livingston [1984] to assume a minimum of 3–4 mm during December through March and a maximum of about 27 mm in August.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

“…Dome C presents lower ground temperatures (i.e., lower telescope emissivity in the infrared), lower wind speeds and lower boundary layer turbulence, as illustrated by Valenziano and Dall'Oglio [1999], Lawrence et al [2004], and Lawrence [2004]. Moreover, observations in the far‐infrared range (i.e., 40–300 μ m) can only be performed with ground‐based instruments in exceptionally dry air conditions, which are sporadically present at Chilean sites [ Giovanelli et al , 2001] but quite common in the Antarctic ones. A definitive comparison in terms of site quality for astronomy between South Pole and Dome C requires more data from the latter site.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization of the atmospheric temperature and moisture conditions above Dome C (Antarctica) during austral summer and fall months

et al. 2006

View full text Add to dashboard Cite

[1] Two sets of radiosounding measurements were taken at Dome C (Antarctica) in December 2003 and January 2003, using RS80-A, RS80-H, and RS90 Vaisala radiosondes, and from March to May 2005, employing the RS92 model. They were examined following accurate correction procedures to remove the main relative humidity dry bias and the temperature and humidity lag errors. The results showed that a strong cooling usually characterizes the thermal conditions of the whole troposphere from December/January to April/May, with an average temperature decrease from 245 to 220 K at the ground, of around 10 K at upper tropospheric levels, and of more than 15 K in the lower stratosphere. The relative humidity data were found to be affected by dry bias of 5-10%, on average, for the RS80-A and RS80-H Humicap sensors and by smaller percentages for the other sensors. The mean monthly vertical profiles of absolute humidity were found to decrease sharply throughout the troposphere, especially within the first 3 km, and to diminish considerably passing from December/January to March/April/ May, with average values of precipitable water decreasing from 0.75 to 0.28 mm, median values from 0.69 to 0.25 mm, and first and third quartiles from 0.60 to 0.22 mm and from 0.87 to 0.34 mm, respectively. The results demonstrate that Dome C (where a permanent scientific station has been open for winter operations since austral winter 2005) is a site of comparable quality to the South Pole for both validation of satellite radiance measurements and astronomic observations in the infrared, submillimetric, and millimetric wavelength range, performed with large telescopes that cannot be carried on satellites.Citation: Tomasi, C., et al. (2006), Characterization of the atmospheric temperature and moisture conditions above Dome C (Antarctica) during austral summer and fall months,

show abstract

Section: Discussion Of the Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Characterization of the atmospheric temperature and moisture conditions above Dome C (Antarctica) during austral summer and fall months

et al. 2006

View full text Add to dashboard Cite

show abstract

“…The ALMA observatory [Wootten and Thompson, 2009] is located on the Chajnantor Plateau at an altitude of 5 km ( Figure 1) and is one of the driest sites on Earth's surface, outside of Antarctica, with median precipitable water vapor of 1.2 mm [Giovanelli and Darling, 2001]. The climate on Chajnantor is characterized by a very dry season during Southern Hemisphere (SH) winter and a wet season referred to as the Altiplanic or Bolivian Winter during SH summer [Garreaud et al, 2003].…”

Section: The Chajnantor Plateaumentioning

confidence: 99%

Water vapor isotopic composition of a stratospheric air intrusion: Measurements from the Chajnantor Plateau, Chile

Galewsky

Samuels-Crow

2014

JGR Atmospheres

View full text Add to dashboard Cite

Measurements of water vapor isotopic composition in stratospheric air intrusions can be used to constrain the dilution of the intrusion as it mixes into the middle troposphere. The intrusion studied here occurred on 17 and 18 August 2012 with measurements obtained at an altitude of 5 km in the Chilean Andes at the Atacama Large Millimeter Array astronomical observatory on the Chajnantor Plateau. Surface ozone concentrations rose 16 ppb in 6 h and were associated with a potential vorticity intrusion on the 330 K isentropic surface. A simulated stratospheric ozone tracer reaching Chajnantor also supports the interpretation of a stratospheric intrusion. Beginning around 18:00 UTC on 17 August, the mixing ratio dropped from 3000 ppmv to 430 ppmv as the water vapor δD values dropped from −153‰ to −438‰ over 13 h while the δ18O values dropped from −20‰ to −63‰. The average mixing ratio, δD, and δ18O values during August 2012 were measured to be 1500 ppmv, −250‰, and −34‰, respectively. The minimum water vapor concentration during the intrusion was in the driest 5% of measurements made during that month, while the minimum δD and δ18O values were within the lowest 0.5% of measurements made during that month. Simple two‐component models of mixing between stratospheric or upper tropospheric air with boundary layer air fail to reproduce observations, but a three‐component mixing model, in which the stratospheric intrusion mixes with an upper tropospheric background air mass, as it mixes with boundary layer air on Chajnantor, matches the observations.

show abstract

“…The characteristic Greenwood Frequency is 2π/t 0 . The values for the atmospheric constant (τ 0 = 0.021s,V 0 = 15m · s −1 , and r 0 = 10cm) are taken from observations made at the Large Atacama Telescope site by Giovanelli et al 2,9 Substituting the values and using the previously defined shift operators we have, 47.831w(s 1 , s 2 , t) + 1.35104w(s 1 , s 2 , t) + . .…”

Section: Modelling Of the Deformable Mirrormentioning

confidence: 99%

Application of distributed control techniques to the adaptive secondary mirror of Cornell's Large Atacama Telescope

2003

View full text Add to dashboard Cite

In this paper we apply, recently developed, distributed control techniques to the control of an adaptive secondary mirror. The control technique implemented uses the l 2 induced norm as a performance criterion. A finite difference model for the mirror is developed using shift operators. We determine the necessary constants from the physical properties of the mirror, from the typical dimensions of such a system, and from our performance requirements for operating the telescope in the near and mid-infrared region.The closed loop system is simulated by modelling the deformable mirror in Abaqus, a commercial finite element software, and by implementing the controller in Matlab.

show abstract

The Optical/Infrared Astronomical Quality of High Atacama Sites. II. Infrared Characteristics

Cited by 53 publications

References 5 publications

Characterization of the atmospheric temperature and moisture conditions above Dome C (Antarctica) during austral summer and fall months

Characterization of the atmospheric temperature and moisture conditions above Dome C (Antarctica) during austral summer and fall months

Water vapor isotopic composition of a stratospheric air intrusion: Measurements from the Chajnantor Plateau, Chile

Application of distributed control techniques to the adaptive secondary mirror of Cornell's Large Atacama Telescope

Contact Info

Product

Resources

About