BICEP/Keck XXII: Analysis of the South Pole Atmosphere for CMB Observations
Abstract
The South Pole is among the driest sites on Earth, and the resulting high atmospheric transparency makes it an excellent site for millimeter-wave astronomical observations. Nevertheless, for bolometric surveys of the cosmic microwave background (CMB), fluctuations in line-of-sight water vapor drive variable atmospheric emission, which has a significant impact on survey sensitivity. We have deployed a water vapor radiometer (WVR) to characterize these fluctuations in space and time and to compare atmospheric and CMB signals with other sites. This WVR has been monitoring conditions from the South Pole over the past nine years, co-located and co-observing with the BICEP series of telescopes. In this work, we analyze the performance of the WVR and the characteristics of the South Pole atmosphere and demonstrate coherent wind-driven transport of water vapor structures across the site. We show that fluctuations in CMB detector timestreams are well correlated with fluctuations in atmospheric water vapor, providing independent justification for baseline filtering procedures used to remove these fluctuations and providing a new pathway to detect and mitigate the temperature-to-polarization leakage that currently limits the precision of ground-based CMB polarization measurements.
Related
- Inflationary models in a minimally coupled f(R,T) gravity: Constraints from Planck, BICEP/Keck, and ACT
- Atmosphere mitigation in cosmic microwave background observations using multifrequency time-domain component separation
- Characterization of the Outer Uranian Rings in the Visual and Near‐IR Using Keck, JWST, and HST Observations
- The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems VIII: patchy forsterite and enstatite clouds in the atmosphere of VHS 1256 b, retrieval lessons learned and outlook to the future
- Atmosphere mitigation in CMB observations using multi-frequency time-domain component separation
BibTeX
@misc{ade2026bicepkeck,
title = {{BICEP/Keck XXII: Analysis of the South Pole Atmosphere for CMB Observations}},
author = {P. A. R. Ade and Z. Ahmed and M. Amiri and D. Barkats and D. Barron and R. Basu Thakur and I. Birdwell and C. A. Bischoff and D. Beck and J. J. Bock and V. Buza and B. Cantrall and J. R. Cheshire IV and J. Connors and J. Cornelison and M. Crumrine and A. J. Cukierman and E. Denison and L. Duband and M. A. Echter and M. Eiben and B. D. Elwood and S. Fatigoni and J. P. Filippini and A. Fortes and M. Gao and C. Giannakopoulos and N. Goeckner-Wald and D. C. Goldfinger and S. Gratton and J. A. Grayson and A. Greathouse and P. K. Grimes and G. Halal and M. Halpern and E. Hand and S. A. Harrison and S. Henderson and T. D. Hoang and J. Hubmayr and H. Hui and K. D. Irwin and J. H. Kang and K. S. Karkare and S. Kefeli and J. M. Kovac and C. Kuo and K. Lasko and K. Lau and M. Lautzenhiser and T. Liu and S. C. Mackey and N. Maher and K. G. Megerian and L. Minutolo and L. Moncelsi and Y. Nakato and H. T. Nguyen and R. O'Brien and S. N. Paine},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.02090},
eprint = {2609.02090},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.02090},
note = {CC0},
}
RIS
TY - UNPB
TI - BICEP/Keck XXII: Analysis of the South Pole Atmosphere for CMB Observations
AU - P. A. R. Ade
AU - Z. Ahmed
AU - M. Amiri
AU - D. Barkats
AU - D. Barron
AU - R. Basu Thakur
AU - I. Birdwell
AU - C. A. Bischoff
AU - D. Beck
AU - J. J. Bock
AU - V. Buza
AU - B. Cantrall
AU - J. R. Cheshire IV
AU - J. Connors
AU - J. Cornelison
AU - M. Crumrine
AU - A. J. Cukierman
AU - E. Denison
AU - L. Duband
AU - M. A. Echter
AU - M. Eiben
AU - B. D. Elwood
AU - S. Fatigoni
AU - J. P. Filippini
AU - A. Fortes
AU - M. Gao
AU - C. Giannakopoulos
AU - N. Goeckner-Wald
AU - D. C. Goldfinger
AU - S. Gratton
AU - J. A. Grayson
AU - A. Greathouse
AU - P. K. Grimes
AU - G. Halal
AU - M. Halpern
AU - E. Hand
AU - S. A. Harrison
AU - S. Henderson
AU - T. D. Hoang
AU - J. Hubmayr
AU - H. Hui
AU - K. D. Irwin
AU - J. H. Kang
AU - K. S. Karkare
AU - S. Kefeli
AU - J. M. Kovac
AU - C. Kuo
AU - K. Lasko
AU - K. Lau
AU - M. Lautzenhiser
AU - T. Liu
AU - S. C. Mackey
AU - N. Maher
AU - K. G. Megerian
AU - L. Minutolo
AU - L. Moncelsi
AU - Y. Nakato
AU - H. T. Nguyen
AU - R. O'Brien
AU - S. N. Paine
PY - 2026
DA - 2026/09/02
PB - arXiv
DO - 10.48550/arxiv.2609.02090
UR - https://arxiv.org/abs/2609.02090
AB - The South Pole is among the driest sites on Earth, and the resulting high atmospheric transparency makes it an excellent site for millimeter-wave astronomical observations. Nevertheless, for bolometric surveys of the cosmic microwave background (CMB), fluctuations in line-of-sight water vapor drive variable atmospheric emission, which has a significant impact on survey sensitivity. We have deployed a water vapor radiometer (WVR) to characterize these fluctuations in space and time and to compare atmospheric and CMB signals with other sites. This WVR has been monitoring conditions from the South Pole over the past nine years, co-located and co-observing with the BICEP series of telescopes. In this work, we analyze the performance of the WVR and the characteristics of the South Pole atmosphere and demonstrate coherent wind-driven transport of water vapor structures across the site. We show that fluctuations in CMB detector timestreams are well correlated with fluctuations in atmospheric water vapor, providing independent justification for baseline filtering procedures used to remove these fluctuations and providing a new pathway to detect and mitigate the temperature-to-polarization leakage that currently limits the precision of ground-based CMB polarization measurements.
ER -