A strong link between variations in sea-ice extent and global atmospheric pressure?
Abstract. This paper reports spectral analyses, using Singular Spectral Analysis, of variations of the Arctic and Antarctic sea-ice extents (SI), and of the atmospheric surface pressure (AP) in both hemispheres (NH and SH). The ice-extents are dominated by a quasi-linear trend over the 42 yr period...
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ftcopernicus:oai:publications.copernicus.org:tcd96324 2023-05-15T14:02:17+02:00 A strong link between variations in sea-ice extent and global atmospheric pressure? Mouël, Jean-Louis Lopes, Fernando Courtillot, Vincent 2021-08-02 application/pdf https://doi.org/10.5194/tc-2021-216 https://tc.copernicus.org/preprints/tc-2021-216/ eng eng doi:10.5194/tc-2021-216 https://tc.copernicus.org/preprints/tc-2021-216/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-2021-216 2021-08-09T16:22:28Z Abstract. This paper reports spectral analyses, using Singular Spectral Analysis, of variations of the Arctic and Antarctic sea-ice extents (SI), and of the atmospheric surface pressure (AP) in both hemispheres (NH and SH). The ice-extents are dominated by a quasi-linear trend over the 42 yr period when data are available (1978–2020) and an annual component. Taken together, these two components represent more than 98 % of the signal variance. Both ice-extent series share the same 5 set of harmonics of the annual component (1/2, 1/3, 1/4 and 1/5 yr). The multi-decadal trends of sea-ice extent in the Arctic and Antarctic are of opposite sign. The series of harmonics of 1 year are consequences of the Earth’s revolution about the Sun. The components with period longer than a year form a set of even harmonics of the Schwabe cycle. The pressure series also exhibits the four harmonics of 1 year, that is not found in many series previously analysed in the same way. This could suggest a connection between variations in pressure and sea-ice extent. Geographical pressure structures (SSA trends) are stable on a 10 decadal to centennial time scale and exhibit a three-fold symmetry in the NH. In the SH that order-3 symmetry is altered by the Ross-Weddell “dipole” pressure anomaly. This anomaly is seen in maps of correlations of variations in sea-ice extent with atmospheric pressure, surface temperature and winds. It fits topographic forcing. There is phase opposition between the annual components of SI and AP in the SH, and the same decreasing phase lag from −30 to −60 days over 42 years for the four harmonic components of SHSI and SHAP. The (negative) sign of the trend of pressure and (positive) sign of the trend of temperature 15 beg for an explanation. The relative change in pressure over the past 50 years is two orders of magnitude smaller than that of warming. This relatively strong warming would be expected to have a larger effect on pressure. The ratio of relative changes of sea-ice extent vs pressure is 400 for the NH and 17 for the SH. The SSA components reported in this paper should help in understanding the mechanisms that govern changes in sea-ice extent: these changes reflect forcings related to the Earth’s revolution about the Sun on the shorter period side, and on the longer period side to the Sun and planets (Jupiter). Advanced 20 explanation of the physics underling these observations may need advances in solving the generalized Navier-Stokes equations, which is very difficult in the spherical case. Text Antarc* Antarctic Arctic Sea ice Copernicus Publications: E-Journals Antarctic Arctic Jupiter ENVELOPE(101.133,101.133,-66.117,-66.117) Weddell |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Abstract. This paper reports spectral analyses, using Singular Spectral Analysis, of variations of the Arctic and Antarctic sea-ice extents (SI), and of the atmospheric surface pressure (AP) in both hemispheres (NH and SH). The ice-extents are dominated by a quasi-linear trend over the 42 yr period when data are available (1978–2020) and an annual component. Taken together, these two components represent more than 98 % of the signal variance. Both ice-extent series share the same 5 set of harmonics of the annual component (1/2, 1/3, 1/4 and 1/5 yr). The multi-decadal trends of sea-ice extent in the Arctic and Antarctic are of opposite sign. The series of harmonics of 1 year are consequences of the Earth’s revolution about the Sun. The components with period longer than a year form a set of even harmonics of the Schwabe cycle. The pressure series also exhibits the four harmonics of 1 year, that is not found in many series previously analysed in the same way. This could suggest a connection between variations in pressure and sea-ice extent. Geographical pressure structures (SSA trends) are stable on a 10 decadal to centennial time scale and exhibit a three-fold symmetry in the NH. In the SH that order-3 symmetry is altered by the Ross-Weddell “dipole” pressure anomaly. This anomaly is seen in maps of correlations of variations in sea-ice extent with atmospheric pressure, surface temperature and winds. It fits topographic forcing. There is phase opposition between the annual components of SI and AP in the SH, and the same decreasing phase lag from −30 to −60 days over 42 years for the four harmonic components of SHSI and SHAP. The (negative) sign of the trend of pressure and (positive) sign of the trend of temperature 15 beg for an explanation. The relative change in pressure over the past 50 years is two orders of magnitude smaller than that of warming. This relatively strong warming would be expected to have a larger effect on pressure. The ratio of relative changes of sea-ice extent vs pressure is 400 for the NH and 17 for the SH. The SSA components reported in this paper should help in understanding the mechanisms that govern changes in sea-ice extent: these changes reflect forcings related to the Earth’s revolution about the Sun on the shorter period side, and on the longer period side to the Sun and planets (Jupiter). Advanced 20 explanation of the physics underling these observations may need advances in solving the generalized Navier-Stokes equations, which is very difficult in the spherical case. |
format |
Text |
author |
Mouël, Jean-Louis Lopes, Fernando Courtillot, Vincent |
spellingShingle |
Mouël, Jean-Louis Lopes, Fernando Courtillot, Vincent A strong link between variations in sea-ice extent and global atmospheric pressure? |
author_facet |
Mouël, Jean-Louis Lopes, Fernando Courtillot, Vincent |
author_sort |
Mouël, Jean-Louis |
title |
A strong link between variations in sea-ice extent and global atmospheric pressure? |
title_short |
A strong link between variations in sea-ice extent and global atmospheric pressure? |
title_full |
A strong link between variations in sea-ice extent and global atmospheric pressure? |
title_fullStr |
A strong link between variations in sea-ice extent and global atmospheric pressure? |
title_full_unstemmed |
A strong link between variations in sea-ice extent and global atmospheric pressure? |
title_sort |
strong link between variations in sea-ice extent and global atmospheric pressure? |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-2021-216 https://tc.copernicus.org/preprints/tc-2021-216/ |
long_lat |
ENVELOPE(101.133,101.133,-66.117,-66.117) |
geographic |
Antarctic Arctic Jupiter Weddell |
geographic_facet |
Antarctic Arctic Jupiter Weddell |
genre |
Antarc* Antarctic Arctic Sea ice |
genre_facet |
Antarc* Antarctic Arctic Sea ice |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2021-216 https://tc.copernicus.org/preprints/tc-2021-216/ |
op_doi |
https://doi.org/10.5194/tc-2021-216 |
_version_ |
1766272454311804928 |