The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background
There is currently an active effort to map the spatial variations in the intensity of the cosmic microwave background (CMB), with different experiments utilizing chopped beam, swept beam, and interferometric approaches to minimize systematic errors. Fluctuations in the brightness of the Earth’s atmo...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.336.9177 2023-05-15T13:36:25+02:00 The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background Oliver P. Lay Nils W. Halverson The Pennsylvania State University CiteSeerX Archives 2000 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.336.9177 http://arxiv.org/pdf/astro-ph/9905369v1.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.336.9177 http://arxiv.org/pdf/astro-ph/9905369v1.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://arxiv.org/pdf/astro-ph/9905369v1.pdf text 2000 ftciteseerx 2016-01-07T23:42:32Z There is currently an active effort to map the spatial variations in the intensity of the cosmic microwave background (CMB), with different experiments utilizing chopped beam, swept beam, and interferometric approaches to minimize systematic errors. Fluctuations in the brightness of the Earth’s atmosphere originating from water vapor are an important source of noise for ground-based instruments. This paper presents a model for the fluctuations and derives simple expressions to predict the contribution of the atmosphere to experimental measurements. Data from the South Pole and from the Atacama Desert in Chile, two of the driest places on Earth, are used to assess the level of fluctuations at each site. The model consists of a layer of turbulence in which the fluctuations follow a modified Kolmogorov power law, with both three- and two-dimensional regimes. The isotropic, three-dimensional case, which applies on small scales, is dominant in most applications. The analysis treats the instruments as window functions that act on the power spectrum of the fluctuations, resulting in a simple pictorial approach analogous to the instrumental window functions that are applied to theoretical models of the CMB angular power spectrum. The South Pole data are from the Python V experiment, and are used to estimate the level of atmospheric fluctuations over 2 months of the summer. The distribution is bimodal, with long periods of very stable conditions (∆Trms < 1 mK in a 6 ◦ strip) broken by occasional periods of much stronger fluctuations (∆Trms> 10 mK), which appear to be associated with clouds. These periods are correlated with a change in wind direction that brings moist air from West Antarctica. 1 Text Antarc* Antarctica South pole South pole West Antarctica Unknown South Pole West Antarctica |
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English |
description |
There is currently an active effort to map the spatial variations in the intensity of the cosmic microwave background (CMB), with different experiments utilizing chopped beam, swept beam, and interferometric approaches to minimize systematic errors. Fluctuations in the brightness of the Earth’s atmosphere originating from water vapor are an important source of noise for ground-based instruments. This paper presents a model for the fluctuations and derives simple expressions to predict the contribution of the atmosphere to experimental measurements. Data from the South Pole and from the Atacama Desert in Chile, two of the driest places on Earth, are used to assess the level of fluctuations at each site. The model consists of a layer of turbulence in which the fluctuations follow a modified Kolmogorov power law, with both three- and two-dimensional regimes. The isotropic, three-dimensional case, which applies on small scales, is dominant in most applications. The analysis treats the instruments as window functions that act on the power spectrum of the fluctuations, resulting in a simple pictorial approach analogous to the instrumental window functions that are applied to theoretical models of the CMB angular power spectrum. The South Pole data are from the Python V experiment, and are used to estimate the level of atmospheric fluctuations over 2 months of the summer. The distribution is bimodal, with long periods of very stable conditions (∆Trms < 1 mK in a 6 ◦ strip) broken by occasional periods of much stronger fluctuations (∆Trms> 10 mK), which appear to be associated with clouds. These periods are correlated with a change in wind direction that brings moist air from West Antarctica. 1 |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Oliver P. Lay Nils W. Halverson |
spellingShingle |
Oliver P. Lay Nils W. Halverson The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
author_facet |
Oliver P. Lay Nils W. Halverson |
author_sort |
Oliver P. Lay |
title |
The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
title_short |
The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
title_full |
The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
title_fullStr |
The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
title_full_unstemmed |
The impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
title_sort |
impact of atmospheric fluctuations on degree-scale imaging of the cosmic microwave background |
publishDate |
2000 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.336.9177 http://arxiv.org/pdf/astro-ph/9905369v1.pdf |
geographic |
South Pole West Antarctica |
geographic_facet |
South Pole West Antarctica |
genre |
Antarc* Antarctica South pole South pole West Antarctica |
genre_facet |
Antarc* Antarctica South pole South pole West Antarctica |
op_source |
http://arxiv.org/pdf/astro-ph/9905369v1.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.336.9177 http://arxiv.org/pdf/astro-ph/9905369v1.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766078174744018944 |