The South Pole is the best available submillimeter observatory site on Earth

Submillimeter astronomy can be pursued only from extremely cold and dry sites, where the atmosphere contains less than 1 mm of precipitable water vapor (PWV). Water vapor is usually the dominant source of opacity, although thousands of other molecular lines also contribute. This "dry air" contribution is important at the Pole. 

Of all ground-based observatory sites that have been tested for submillimeter-wave sky quality, the best results have come from the Amundsen-Scott South Pole Station.

The Antarctic Plateau is unique among observatory sites for unusually low wind speeds, absence of rain, and the consistent clarity of the submillimeter sky. The highest wind speed at the South Pole between 1957 and 1983 was only 24 m s^-1, and there are many months during which the wind speed does not exceed 12 m s^-1. Ice cores show no rain at the Pole for thousands of years.  Schwerdtfeger (Climate of the Antarctic, Elsevier 1984) has comprehensively reviewed the climate of the Antarctic Plateau.

Precipitable Water Vapor (PWV)

PWV is the most important input parameter for atmospheric models, and is a measure of the total water vapor content of the atmosphere.  PWV at the South Pole is exceptionally low and stable.  

The PWV at the South Pole is consistently better than Mauna Kea and the Chajnantor site in the Atacama desert. 

Compared to these other observatory sites, PWV at the Pole is 4 to 10 times smaller.

 

Opacity as a function of frequency and time

Atmospheric opacity to millimeter and submillimeter waves has been measured by sky dip techniques at several wavelengths.   

The submillimeter-wave transparency at the South Pole is consistently better than Mauna Kea and Chajnantor. 

Compared to these other observatory sites, atmospheric opacity at the Pole is 1.5 to 4 times smaller.

 

Sky noise

Sky noise causes systematic errors in submillimeter-wave astronomical measurements.   

The submillimeter-wave sky noise at the South Pole is consistently much better than Mauna Kea and Chajnantor. 

Compared to these other observatory sites, sky noise at the Pole is 10 to 50 times smaller.