Speaker
Description
Atmospheric fluctuation is one of the sources of low-frequency
noise in ground-based CMB experiments. Since atmospheric emissions are
almost unpolarized, they do not directly increase the noise of
polarization measurements as far as instruments are well-calibrated.
Tropospheric ice clouds, however, scatter upwelling thermal radiations
and produce polarized signals. In practice, most of the polarized
bursts in the POLARBEAR data occur during cloudy observations. Cloud
polarization is a critical noise since it is correlated among
detectors and cannot be suppressed by the polarization modulation
technique. In POLARBEAR, we apply data selection associated with
polarized bursts and cut several percent of the data. We demonstrate
example data and discuss impacts on the CMB measurements.
