Characterizing the Atmospheric Conditions at Cosmic Microwave Background Observatories

Ground-based Cosmic Microwave Background (CMB) observations are limited by atmospheric emission and absorption in the millimeter-wave range. Components of the atmosphere, such as water vapor and ice, have time-varying impacts on atmospheric properties at these wavelengths. The precipitable water vapor (PWV) is the amount of water vapor that is contained in a vertical column from the ground to the top of the atmosphere. The PWV varies over time and space, which causes varying continuum emission in the observing frequency bands. A better characterization of the local PWV will help future CMB observations. We present simulations for different atmospheric conditions. We also characterize the PWV at the South Pole over the course of one year.