Transient eastward-propagating long-period waves observed over the South Pole
International audience Observations of the horizontal wind field over the South Pole were made during 1995 using a meteor radar. These data have revealed the presence of a rich spectrum of waves over the South Pole with a distinct annual occurrence. Included in this spectrum are long-period waves, w...
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ftinsu:oai:HAL:hal-00316474v1 2023-11-12T04:26:16+01:00 Transient eastward-propagating long-period waves observed over the South Pole Palo, S. E. Portnyagin, Y. I. Forbes, J. M. Makarov, N. A. Merzlyakov, E. G. University of Colorado Boulder Institute for Experimental Meteorology 1998 https://hal.science/hal-00316474 https://hal.science/hal-00316474/document https://hal.science/hal-00316474/file/angeo-16-1486-1998.pdf en eng HAL CCSD European Geosciences Union hal-00316474 https://hal.science/hal-00316474 https://hal.science/hal-00316474/document https://hal.science/hal-00316474/file/angeo-16-1486-1998.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316474 Annales Geophysicae, 1998, 16 (11), pp.1486-1500 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 1998 ftinsu 2023-10-25T16:25:36Z International audience Observations of the horizontal wind field over the South Pole were made during 1995 using a meteor radar. These data have revealed the presence of a rich spectrum of waves over the South Pole with a distinct annual occurrence. Included in this spectrum are long-period waves, whose periods are greater than one solar day, which are propagating eastward. These waves exhibit a distinct seasonal occurrence where the envelope of wave periods decreases from a period of 10 days near the fall equinox to a minimum of 2 days near the winter solstice and then progresses towards a period near 10 days at the spring equinox. Computation of the meridional gradient of quasi-geostrophic potential vorticity has revealed a region in the high-latitude upper mesosphere which could support an instability and serve as a source for these waves. Estimation of the wave periods which would be generated from an instability in this region closely resembles the observed seasonal variation in wave periods over the South Pole. These results are consistent with the hypothesis that the observed eastward propagating long-period waves over the South Pole are generated by an instability in the polar upper mesosphere. However, given our limited data set we cannot rule out a stratospheric source. Embedded in this spectrum of eastward propagating waves during the austral winter are a number of distinct wave events. Eight such wave events have been identified and localized using a constant- Q filter bank. The periods of these wave events ranges from 1.7 to 9.8 days and all exist for at least 3 wave periods. Least squares analysis has revealed that a number of these events are inconsistent with a wave propagating zonally around the geographic pole and could be related to waves propagating around a dynamical pole which is offset from the geographic pole. Additionally, one event which was observed appears to be a standing oscillation. Article in Journal/Newspaper South pole Institut national des sciences de l'Univers: HAL-INSU Austral South Pole |
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Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Palo, S. E. Portnyagin, Y. I. Forbes, J. M. Makarov, N. A. Merzlyakov, E. G. Transient eastward-propagating long-period waves observed over the South Pole |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Observations of the horizontal wind field over the South Pole were made during 1995 using a meteor radar. These data have revealed the presence of a rich spectrum of waves over the South Pole with a distinct annual occurrence. Included in this spectrum are long-period waves, whose periods are greater than one solar day, which are propagating eastward. These waves exhibit a distinct seasonal occurrence where the envelope of wave periods decreases from a period of 10 days near the fall equinox to a minimum of 2 days near the winter solstice and then progresses towards a period near 10 days at the spring equinox. Computation of the meridional gradient of quasi-geostrophic potential vorticity has revealed a region in the high-latitude upper mesosphere which could support an instability and serve as a source for these waves. Estimation of the wave periods which would be generated from an instability in this region closely resembles the observed seasonal variation in wave periods over the South Pole. These results are consistent with the hypothesis that the observed eastward propagating long-period waves over the South Pole are generated by an instability in the polar upper mesosphere. However, given our limited data set we cannot rule out a stratospheric source. Embedded in this spectrum of eastward propagating waves during the austral winter are a number of distinct wave events. Eight such wave events have been identified and localized using a constant- Q filter bank. The periods of these wave events ranges from 1.7 to 9.8 days and all exist for at least 3 wave periods. Least squares analysis has revealed that a number of these events are inconsistent with a wave propagating zonally around the geographic pole and could be related to waves propagating around a dynamical pole which is offset from the geographic pole. Additionally, one event which was observed appears to be a standing oscillation. |
author2 |
University of Colorado Boulder Institute for Experimental Meteorology |
format |
Article in Journal/Newspaper |
author |
Palo, S. E. Portnyagin, Y. I. Forbes, J. M. Makarov, N. A. Merzlyakov, E. G. |
author_facet |
Palo, S. E. Portnyagin, Y. I. Forbes, J. M. Makarov, N. A. Merzlyakov, E. G. |
author_sort |
Palo, S. E. |
title |
Transient eastward-propagating long-period waves observed over the South Pole |
title_short |
Transient eastward-propagating long-period waves observed over the South Pole |
title_full |
Transient eastward-propagating long-period waves observed over the South Pole |
title_fullStr |
Transient eastward-propagating long-period waves observed over the South Pole |
title_full_unstemmed |
Transient eastward-propagating long-period waves observed over the South Pole |
title_sort |
transient eastward-propagating long-period waves observed over the south pole |
publisher |
HAL CCSD |
publishDate |
1998 |
url |
https://hal.science/hal-00316474 https://hal.science/hal-00316474/document https://hal.science/hal-00316474/file/angeo-16-1486-1998.pdf |
geographic |
Austral South Pole |
geographic_facet |
Austral South Pole |
genre |
South pole |
genre_facet |
South pole |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316474 Annales Geophysicae, 1998, 16 (11), pp.1486-1500 |
op_relation |
hal-00316474 https://hal.science/hal-00316474 https://hal.science/hal-00316474/document https://hal.science/hal-00316474/file/angeo-16-1486-1998.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782340320585842688 |