In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996
For ease in discerning an Antarctic circumpolar wave in the perimeter of the ice pack, we construct a time series of the sea ice extents (essentially the area within the ice perimeter) in 1-degree longitudinal sectors for the period 1978–1996, as observed with the multichannel microwave imagers on b...
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Norwegian Polar Institute
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ftjpolarres:oai:journals.openacademia.net:article/2226 2023-05-15T14:01:21+02:00 In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 Gloersen, Per Huang, Norden E. 1999-01-12 application/pdf https://polarresearch.net/index.php/polar/article/view/2226 https://doi.org/10.3402/polar.v18i2.6570 eng eng Norwegian Polar Institute https://polarresearch.net/index.php/polar/article/view/2226/5477 https://polarresearch.net/index.php/polar/article/view/2226 doi:10.3402/polar.v18i2.6570 Copyright (c) 2018 Polar Research Polar Research; Vol. 18 No. 2 (1999): Special issue: Proceedings of the International Symposium on Polar Aspects of Global Change; 167-173 1751-8369 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 1999 ftjpolarres https://doi.org/10.3402/polar.v18i2.6570 2021-11-11T19:12:21Z For ease in discerning an Antarctic circumpolar wave in the perimeter of the ice pack, we construct a time series of the sea ice extents (essentially the area within the ice perimeter) in 1-degree longitudinal sectors for the period 1978–1996, as observed with the multichannel microwave imagers on board the NASA Nimbus 7 and the DOD (Dept. of Defense) DMSP (Defense Meteorological Satellite Program) F8. F11, and F13 satellites. After converting the time series into complex numbers by means of a Hilbert transform, we decompose the time series of the 360 sectors into its complex principal components (CPCs), effectively separating the spatial and temporal values. Then we decompose the real and imaginary parts of the temporal portions of the first three CPCs (complex principal compenents) by Empirical Mode Decomposition into their intrinsic modes, each representing a narrow frequency band, resulting in a collection of three CPCs for each intrinsic mode. Finally, we reconstruct the data in two different ways. First, we low-pass filter the data by combining all of the intrinsic modes of each CPC with periods longer than two years, which we designate as low-pass filtered. Next, we select the intrinsic mode of each CPC with periods of approximately four years, which we designate the quasiquadrennial (QQ) modes. The low-pass filtered time series shows eastward propagating azimuthal motion in the Ross and Weddell Seas, but no clearly circumpolar motion. The QQ time series, on the other hand, clearly shows castward propagating circumpolar waves, but with occasional retrograde motion to the west. Article in Journal/Newspaper Antarc* Antarctic ice pack Polar Research Sea ice Polar Research (E-Journal) Antarctic Weddell Polar Research 18 2 167 173 |
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Open Polar |
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Polar Research (E-Journal) |
op_collection_id |
ftjpolarres |
language |
English |
description |
For ease in discerning an Antarctic circumpolar wave in the perimeter of the ice pack, we construct a time series of the sea ice extents (essentially the area within the ice perimeter) in 1-degree longitudinal sectors for the period 1978–1996, as observed with the multichannel microwave imagers on board the NASA Nimbus 7 and the DOD (Dept. of Defense) DMSP (Defense Meteorological Satellite Program) F8. F11, and F13 satellites. After converting the time series into complex numbers by means of a Hilbert transform, we decompose the time series of the 360 sectors into its complex principal components (CPCs), effectively separating the spatial and temporal values. Then we decompose the real and imaginary parts of the temporal portions of the first three CPCs (complex principal compenents) by Empirical Mode Decomposition into their intrinsic modes, each representing a narrow frequency band, resulting in a collection of three CPCs for each intrinsic mode. Finally, we reconstruct the data in two different ways. First, we low-pass filter the data by combining all of the intrinsic modes of each CPC with periods longer than two years, which we designate as low-pass filtered. Next, we select the intrinsic mode of each CPC with periods of approximately four years, which we designate the quasiquadrennial (QQ) modes. The low-pass filtered time series shows eastward propagating azimuthal motion in the Ross and Weddell Seas, but no clearly circumpolar motion. The QQ time series, on the other hand, clearly shows castward propagating circumpolar waves, but with occasional retrograde motion to the west. |
format |
Article in Journal/Newspaper |
author |
Gloersen, Per Huang, Norden E. |
spellingShingle |
Gloersen, Per Huang, Norden E. In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 |
author_facet |
Gloersen, Per Huang, Norden E. |
author_sort |
Gloersen, Per |
title |
In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 |
title_short |
In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 |
title_full |
In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 |
title_fullStr |
In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 |
title_full_unstemmed |
In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996 |
title_sort |
in search of an elusive antarctic circumpolar wave in sea ice extents: 1978–1996 |
publisher |
Norwegian Polar Institute |
publishDate |
1999 |
url |
https://polarresearch.net/index.php/polar/article/view/2226 https://doi.org/10.3402/polar.v18i2.6570 |
geographic |
Antarctic Weddell |
geographic_facet |
Antarctic Weddell |
genre |
Antarc* Antarctic ice pack Polar Research Sea ice |
genre_facet |
Antarc* Antarctic ice pack Polar Research Sea ice |
op_source |
Polar Research; Vol. 18 No. 2 (1999): Special issue: Proceedings of the International Symposium on Polar Aspects of Global Change; 167-173 1751-8369 |
op_relation |
https://polarresearch.net/index.php/polar/article/view/2226/5477 https://polarresearch.net/index.php/polar/article/view/2226 doi:10.3402/polar.v18i2.6570 |
op_rights |
Copyright (c) 2018 Polar Research |
op_doi |
https://doi.org/10.3402/polar.v18i2.6570 |
container_title |
Polar Research |
container_volume |
18 |
container_issue |
2 |
container_start_page |
167 |
op_container_end_page |
173 |
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1766271080043905024 |