Water vapor in the atmosphere: an examination for CARMA phase correction

We report on the current progress of the water vapor radiometer (WVR) phase correction project for the Combined Array for Research in Millimeter-wave Astronomy (CARMA). CARMA is a new millimeter array that merges the Owens Valley Radio Observatory (OVRO) array, the Berkeley-Illinois-Maryland Association (BIMA) array and eventually the Sunyaev-Zel'dovich Array (SZA). WVRs are designed for phase correction by monitoring the water vapor in the atmosphere along the line of sight toward astronomical sources. In addition, we discuss the stability of the current OVRO water vapor radiometers in preparation for testing at the CARMA site. We will systematically analyze the receivers with atmospheric correlations to decouple the effects of instrumentation and atmospheric noise. Finally, we report on the status of the correlation receivers in development.