Atmospheric emission is a dominant source of disturbance in ground-based astronomy at millimetric wavelengths .
The Antarctic plateau is recognized to be an ideal site for millimetric and sub-millimetric observations , and the French/Italian base of Dome Concordia is among the best sites on Earth for these observations .
In this paper we present measurements at Dome Concordia of the atmospheric emission in intensity and polarization at 2 mm wavelength , one of the best observational frequencies for Cosmic Microwave Background ( CMB ) observations when considering cosmic signal intensity , atmospheric transmission , detectors sensitivity , and foreground removal .
Using the BRAIN-pathfinder experiment , we have performed measurements of the atmospheric emission at 150 GHz .
Careful characterization of the air-mass synchronous emission has been performed , acquiring more that 380 elevation scans ( i.e .
“ skydip ” ) during the third BRAIN-pathfinder summer campaign in December 2009/January 2010 .
The extremely high transparency of the Antarctic atmosphere over Dome Concordia is proven by the very low measured optical depth : < \tau _ { I } > = 0.050 \pm 0.003 \pm 0.011 where the first error is statistical and the second is systematic error .
Mid term stability , over the summer campaign , of the atmosphere emission has also been studied .
Adapting the radiative transfer atmosphere emission model am to the particular conditions found at Dome Concordia , we also infer the level of the precipitable water vapor ( PWV ) content of the atmosphere , notoriously the main source of disturbance in millimetric astronomy ( < PWV > = 0.77 \pm 0.06 \pm ^ { 0.15 } _ { 0.12 } mm ) .
Upper limits on the air-mass correlated polarized signal are also placed for the first time .
The degree of circular polarization of atmospheric emission is found to be lower than 0.2 % ( 95 % CL ) , while the degree of linear polarization is found to be lower than 0.1 % ( 95 % CL ) .
These limits include signal-correlated instrumental spurious polarization .