An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3

<p>Utilising the 20th Century Reanalysis version 3 (20CRv3), we examine changes in the extent and rate of autumn Eurasian snow cover (SC) advance and the temporal variability in the SC–Arctic Oscillation (AO) relationship. Novel aspects are (i) analysis back to 1836, (ii) adjusting the reanaly...

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Main Author: G. J. Marshall
Format: Article
Language:English
Published: Copernicus Publications 2025-02-01
Series:The Cryosphere
Online Access:https://tc.copernicus.org/articles/19/663/2025/tc-19-663-2025.pdf
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author G. J. Marshall
author_facet G. J. Marshall
author_sort G. J. Marshall
collection DOAJ
description <p>Utilising the 20th Century Reanalysis version 3 (20CRv3), we examine changes in the extent and rate of autumn Eurasian snow cover (SC) advance and the temporal variability in the SC–Arctic Oscillation (AO) relationship. Novel aspects are (i) analysis back to 1836, (ii) adjusting the reanalysis SC through comparison with observations, and (iii) analysing the statistical significance of the frequency of periods of significant SC–AO relationships to determine whether these connections can be distinguished from stochastic processes. Across the full span of 20CRv3, there is a small increase in mean September Eurasian SC. In contrast, there have been significant decreases in both October and November SC. Trends over the past 50 years demonstrate a slowing and accelerating of snow advance in October and November, respectively, corresponding to a postponement of SC onset. Robust relationships exist between September and October Eurasian SC and the winter AO across the 180-year span of 20CRv3. Within Eurasia, we reveal a strong SC–AO relationship with September SC in northeastern Eurasia, which has not been noted previously. The associated spatial pattern of September tropospheric height anomalies closely matches the positive phase of the western Pacific teleconnection pattern. As many other factors are known to impact the winter AO, and these predominantly occur in October or November, the residual September SC signal-to-noise ratio in the winter atmosphere is small. Therefore, model experiments in which only the magnitude of September SC is perturbed will be necessary to elucidate the processes behind this newly described SC–AO relationship.</p>
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institution Kabale University
issn 1994-0416
1994-0424
language English
publishDate 2025-02-01
publisher Copernicus Publications
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series The Cryosphere
spelling doaj-art-f29dce388b0c43ea8acf8ae1651972482025-02-11T11:20:20ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242025-02-011966368310.5194/tc-19-663-2025An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3G. J. Marshall0British Antarctic Survey, Cambridge, CB3 0ET, UK<p>Utilising the 20th Century Reanalysis version 3 (20CRv3), we examine changes in the extent and rate of autumn Eurasian snow cover (SC) advance and the temporal variability in the SC–Arctic Oscillation (AO) relationship. Novel aspects are (i) analysis back to 1836, (ii) adjusting the reanalysis SC through comparison with observations, and (iii) analysing the statistical significance of the frequency of periods of significant SC–AO relationships to determine whether these connections can be distinguished from stochastic processes. Across the full span of 20CRv3, there is a small increase in mean September Eurasian SC. In contrast, there have been significant decreases in both October and November SC. Trends over the past 50 years demonstrate a slowing and accelerating of snow advance in October and November, respectively, corresponding to a postponement of SC onset. Robust relationships exist between September and October Eurasian SC and the winter AO across the 180-year span of 20CRv3. Within Eurasia, we reveal a strong SC–AO relationship with September SC in northeastern Eurasia, which has not been noted previously. The associated spatial pattern of September tropospheric height anomalies closely matches the positive phase of the western Pacific teleconnection pattern. As many other factors are known to impact the winter AO, and these predominantly occur in October or November, the residual September SC signal-to-noise ratio in the winter atmosphere is small. Therefore, model experiments in which only the magnitude of September SC is perturbed will be necessary to elucidate the processes behind this newly described SC–AO relationship.</p>https://tc.copernicus.org/articles/19/663/2025/tc-19-663-2025.pdf
spellingShingle G. J. Marshall
An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3
The Cryosphere
title An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3
title_full An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3
title_fullStr An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3
title_full_unstemmed An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3
title_short An examination of changes in autumn Eurasian snow cover and its relationship with the winter Arctic Oscillation using 20th Century Reanalysis version 3
title_sort examination of changes in autumn eurasian snow cover and its relationship with the winter arctic oscillation using 20th century reanalysis version 3
url https://tc.copernicus.org/articles/19/663/2025/tc-19-663-2025.pdf
work_keys_str_mv AT gjmarshall anexaminationofchangesinautumneurasiansnowcoveranditsrelationshipwiththewinterarcticoscillationusing20thcenturyreanalysisversion3
AT gjmarshall examinationofchangesinautumneurasiansnowcoveranditsrelationshipwiththewinterarcticoscillationusing20thcenturyreanalysisversion3