Understanding Atmospheric Turbulence at \(\lambda\) = 1mm

Abstract

The Atacama Cosmology Telescope measures the anisotropy of the CMB at frequencies \(\sim\) 150 GHz ( \(\lambda\) \(\sim\)1mm). Although Atacama is the driest non-polar desert in the world, ACT still contends with extensive thermal loading due to emissions from Precipitable Water Vapor (PWV) in the atmosphere. Most of the PWV in the atmosphere resides in the lowest layer of the atmosphere, the troposphere, which is characterized by strong vertical mixing and turbulence. We investigate how the distribution of water vapor in the atmosphere uctuates due to turbulence. Using Kolmogorov's two-thirds law, which states that the water vapor in the atmosphere follows a power law distribution, we simulate atmospheric water vapor to characterize how the spatial and temporal structure of water in the sky manifests in detector data.