The effects of Forbush decreases on Antarctic climate variability: a re-assessment
In an attempt to test the validity of a relationship between Galactic cosmic rays (GCRs) and cloud cover, a range of past studies have performed composite analysis based around Forbush decrease (FD) events. These studies have produced a range of conflicting results, consequently reducing confidence...
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ftcopernicus:oai:publications.copernicus.org:acpd523 2023-05-15T13:45:55+02:00 The effects of Forbush decreases on Antarctic climate variability: a re-assessment Laken, B. A. Kniveton, D. R. 2018-08-11 application/pdf https://doi.org/10.5194/acpd-9-10575-2009 https://www.atmos-chem-phys-discuss.net/acp-2009-140/ eng eng doi:10.5194/acpd-9-10575-2009 https://www.atmos-chem-phys-discuss.net/acp-2009-140/ eISSN: 1680-7324 Text 2018 ftcopernicus https://doi.org/10.5194/acpd-9-10575-2009 2019-12-24T09:57:54Z In an attempt to test the validity of a relationship between Galactic cosmic rays (GCRs) and cloud cover, a range of past studies have performed composite analysis based around Forbush decrease (FD) events. These studies have produced a range of conflicting results, consequently reducing confidence in the existence of a GCR-cloud link. A potential reason why past FD based studies have failed to identify a consistent relationship may be that the FD events themselves are too poorly defined, and require calibration prior to analysis. Drawing from an initial sample of 48 FD events taken from multiple studies this work attempts to isolate a GCR decrease of greater magnitude and coherence than has been demonstrated by past studies. After this calibration composite analysis revealed increases in high level (10–180 mb) cloud cover (of ~20%) occurred over the Antarctic plateau in conjunction with decreases in the rate of GCR flux during austral winter (these results are broadly opposite to those of past studies). The cloud changes occurred in conjunction with locally significant surface level air temperature increases over the Antarctic plateau (~4 K) and temperature decreases over the Ross Ice Sheet (~8 K). These temperature variations appear to be indirectly linked to cloud via anomalous surface level winds rather than a direct radiative forcing. These results provide good evidence of a relationship between daily timescale GCR variations and Antarctic climate variability. Text Antarc* Antarctic Ice Sheet Copernicus Publications: E-Journals Antarctic Austral The Antarctic |
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Copernicus Publications: E-Journals |
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English |
description |
In an attempt to test the validity of a relationship between Galactic cosmic rays (GCRs) and cloud cover, a range of past studies have performed composite analysis based around Forbush decrease (FD) events. These studies have produced a range of conflicting results, consequently reducing confidence in the existence of a GCR-cloud link. A potential reason why past FD based studies have failed to identify a consistent relationship may be that the FD events themselves are too poorly defined, and require calibration prior to analysis. Drawing from an initial sample of 48 FD events taken from multiple studies this work attempts to isolate a GCR decrease of greater magnitude and coherence than has been demonstrated by past studies. After this calibration composite analysis revealed increases in high level (10–180 mb) cloud cover (of ~20%) occurred over the Antarctic plateau in conjunction with decreases in the rate of GCR flux during austral winter (these results are broadly opposite to those of past studies). The cloud changes occurred in conjunction with locally significant surface level air temperature increases over the Antarctic plateau (~4 K) and temperature decreases over the Ross Ice Sheet (~8 K). These temperature variations appear to be indirectly linked to cloud via anomalous surface level winds rather than a direct radiative forcing. These results provide good evidence of a relationship between daily timescale GCR variations and Antarctic climate variability. |
format |
Text |
author |
Laken, B. A. Kniveton, D. R. |
spellingShingle |
Laken, B. A. Kniveton, D. R. The effects of Forbush decreases on Antarctic climate variability: a re-assessment |
author_facet |
Laken, B. A. Kniveton, D. R. |
author_sort |
Laken, B. A. |
title |
The effects of Forbush decreases on Antarctic climate variability: a re-assessment |
title_short |
The effects of Forbush decreases on Antarctic climate variability: a re-assessment |
title_full |
The effects of Forbush decreases on Antarctic climate variability: a re-assessment |
title_fullStr |
The effects of Forbush decreases on Antarctic climate variability: a re-assessment |
title_full_unstemmed |
The effects of Forbush decreases on Antarctic climate variability: a re-assessment |
title_sort |
effects of forbush decreases on antarctic climate variability: a re-assessment |
publishDate |
2018 |
url |
https://doi.org/10.5194/acpd-9-10575-2009 https://www.atmos-chem-phys-discuss.net/acp-2009-140/ |
geographic |
Antarctic Austral The Antarctic |
geographic_facet |
Antarctic Austral The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acpd-9-10575-2009 https://www.atmos-chem-phys-discuss.net/acp-2009-140/ |
op_doi |
https://doi.org/10.5194/acpd-9-10575-2009 |
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1766232657305272320 |