Assessments of Ali, Dome A, and Summit Camp for Mm-wave Observations Using MERRA-2 Reanalysis

Abstract

The latest MERRA-2 reanalysis of the modern satellite measurements provides unprecedented uniformity and fidelity for the atmospheric data. In this paper, these data are used to evaluate five sites for millimeter-wave (mm-wave) observations. These include two established sites (South Pole and Chajnantor, Atacama), and three new sites (Ali, Tibet; Dome A, Antarctica; and Summit Camp, Greenland). Atmospheric properties including precipitable water vapor (PWV), sky brightness temperature fluctuations, ice and liquid water paths are derived and compared. Dome A emerges to be the best among those evaluated, with PWV and fluctuations smaller than the second-best site, South Pole, by more than a factor of 2. It is found that the higher site in Ali (6,100 m) is on par with Cerro Chajnantor (5,612 m) in terms of transmission and stability. The lower site in Ali (5,250 m) planned for first stage of observations at 90/150GHz provides conditions comparable to those on the Chajnantor Plateau. These analyses confirm Ali to be an excellent mm-wave site on the Northern Hemisphere that will complement well-established sites on the Southern Hemisphere. It is also found in this analysis that the observing conditions at Summit Camp are comparable to Cerro Chajnantor. Although it is more affected by the presence of liquid water clouds.

14 pages, 8 figures

References in corpus (3)

• The Event Horizon Telescope: exploring strong gravity and accretion physics
• 3.5-Year Monitoring of 225 GHz Opacity at the Summit of Greenland
• Analysis of the distribution of precipitable water vapor in the Chajnantor area

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• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• Twenty years of PWV measurements in the Chajnantor Area
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• Study on the filters of atmospheric contamination in ground based CMB observation
• Testing the coupling of dark radiations in light of the Hubble tension
• First Submillimeter Lights from Dome A: Tracing the Carbon Cycle in the Feedback of Massive Stars