Measurements of tropospheric ice clouds with a ground-based CMB polarization experiment, POLARBEAR
Abstract
The polarization of the atmosphere has been a long-standing concern for ground-based experiments targeting cosmic microwave background (CMB) polarization. Ice crystals in upper tropospheric clouds scatter thermal radiation from the ground and produce a horizontally-polarized signal. We report the detailed analysis of the cloud signal using a ground-based CMB experiment, POLARBEAR, located at the Atacama desert in Chile and observing at 150 GHz. We observe horizontally-polarized temporal increases of low-frequency fluctuations ("polarized bursts," hereafter) of 0.1 K when clouds appear in a webcam monitoring the telescope and the sky. The hypothesis of no correlation between polarized bursts and clouds is rejected with 24 statistical significance using three years of data. We consider many other possibilities including instrumental and environmental effects, and find no other reasons other than clouds that can explain the data better. We also discuss the impact of the cloud polarization on future ground-based CMB polarization experiments.
Keywords
Cite
@article{arxiv.1809.06556,
title = {Measurements of tropospheric ice clouds with a ground-based CMB polarization experiment, POLARBEAR},
author = {Satoru Takakura and Mario A. O. Aguilar-Faúndez and Yoshiki Akiba and Kam Arnold and Carlo Baccigalupi and Darcy Barron and Dominic Beck and Federico Bianchini and David Boettger and Julian Borrill and Kolen Cheung and Yuji Chinone and Tucker Elleflot and Josquin Errard and Giulio Fabbian and Chang Feng and Neil Goeckner-Wald and Takaho Hamada and Masaya Hasegawa and Masashi Hazumi and Logan Howe and Daisuke Kaneko and Nobuhiko Katayama and Brian Keating and Reijo Keskitalo and Theodore Kisner and Nicoletta Krachmalnicoff and Akito Kusaka and Adrian T. Lee and Lindsay N. Lowry and Frederick T. Matsuda and Andrew J. May and Yuto Minami and Martin Navaroli and Haruki Nishino and Lucio Piccirillo and Davide Poletti and Giuseppe Puglisi and Christian L. Reichardt and Yuuko Segawa and Maximiliano Silva-Feaver and Praween Siritanasak and Aritoki Suzuki and Osamu Tajima and Sayuri Takatori and Daiki Tanabe and Grant P. Teply and Calvin Tsai},
journal= {arXiv preprint arXiv:1809.06556},
year = {2019}
}
Comments
14 pages, 12 figures, 1 table, Submitted to ApJ