Sea surface height variability in drake passage
Intercomparisons between altimeter sea surface height (SSH) and open-ocean in situ observations have been limited owing to sparse available datasets. Here, SSH anomaly (SSHA) determined from current and pressure recording inverted echo sounders (CPIES) from the cDrake experiment were compared with a...
Published in: | Journal of Atmospheric and Oceanic Technology |
---|---|
Main Authors: | , , |
Format: | Text |
Language: | unknown |
Published: |
DigitalCommons@URI
2016
|
Subjects: | |
Online Access: | https://digitalcommons.uri.edu/gsofacpubs/1214 https://doi.org/10.1175/JTECH-D-15-0249.1 |
id |
ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-2189 |
---|---|
record_format |
openpolar |
spelling |
ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-2189 2023-12-03T10:12:41+01:00 Sea surface height variability in drake passage Donohue, Kathleen A. Kennelly, Maureen A. Cutting, Amy 2016-04-01T07:00:00Z https://digitalcommons.uri.edu/gsofacpubs/1214 https://doi.org/10.1175/JTECH-D-15-0249.1 unknown DigitalCommons@URI https://digitalcommons.uri.edu/gsofacpubs/1214 doi:10.1175/JTECH-D-15-0249.1 https://doi.org/10.1175/JTECH-D-15-0249.1 Graduate School of Oceanography Faculty Publications Altimetry Anomalies In situ oceanic observations Observational techniques and algorithms Oceanic variability Satellite observations Variability text 2016 ftunivrhodeislan https://doi.org/10.1175/JTECH-D-15-0249.1 2023-11-06T19:09:56Z Intercomparisons between altimeter sea surface height (SSH) and open-ocean in situ observations have been limited owing to sparse available datasets. Here, SSH anomaly (SSHA) determined from current and pressure recording inverted echo sounders (CPIES) from the cDrake experiment were compared with an up-to-date AVISO-mapped product. Meandering Antarctic Circumpolar Current (ACC) fronts in the passage interior elevated SSHA variance; south of the Shackleton Fracture Zone and along the northern continental slope, the variance decreased by factors between 6 and 10. In situ analysis focused on the two constituents of SSHA, SSHAref determined from bottom pressure and SSHAbcb calculated from geopotential height referenced to the bottom. The peak variance of both SSHAbcb and SSHAref occurred in the energetic region between the Subantarctic Front and the Polar Front. The contribution of SSHAbcb to total SSHA variance was greater than 40% at all sites and averaged over all sites it was 73%. For most sites, high-frequency (> 1/20 cpd) SSHAbcb signals dominated total high-frequency variance. Aliasing of high-frequency signals resulting from 10-day altimeter sampling was assessed. The fraction of aliased energy at frequencies longer than 1/50 cpd for sites at and north of the Shackleton Fracture Zone approached 0.25 and approached 0.50 for southern sites. CPIES and mapped altimeter SSHA agreed well. The mean correlation coefficient was 0.82 and the mean RMS difference was 0.075 m. Correlations between CPIES and AVISO were notably poorer at the northern and southern boundaries. RMS differences increased as a function of CPIES high-frequency SSHA variance because the mapped altimetry product does not resolve these frequencies. Text Antarc* Antarctic Drake Passage University of Rhode Island: DigitalCommons@URI Antarctic Drake Passage Shackleton Shackleton Fracture Zone ENVELOPE(-60.000,-60.000,-60.000,-60.000) Journal of Atmospheric and Oceanic Technology 33 4 669 683 |
institution |
Open Polar |
collection |
University of Rhode Island: DigitalCommons@URI |
op_collection_id |
ftunivrhodeislan |
language |
unknown |
topic |
Altimetry Anomalies In situ oceanic observations Observational techniques and algorithms Oceanic variability Satellite observations Variability |
spellingShingle |
Altimetry Anomalies In situ oceanic observations Observational techniques and algorithms Oceanic variability Satellite observations Variability Donohue, Kathleen A. Kennelly, Maureen A. Cutting, Amy Sea surface height variability in drake passage |
topic_facet |
Altimetry Anomalies In situ oceanic observations Observational techniques and algorithms Oceanic variability Satellite observations Variability |
description |
Intercomparisons between altimeter sea surface height (SSH) and open-ocean in situ observations have been limited owing to sparse available datasets. Here, SSH anomaly (SSHA) determined from current and pressure recording inverted echo sounders (CPIES) from the cDrake experiment were compared with an up-to-date AVISO-mapped product. Meandering Antarctic Circumpolar Current (ACC) fronts in the passage interior elevated SSHA variance; south of the Shackleton Fracture Zone and along the northern continental slope, the variance decreased by factors between 6 and 10. In situ analysis focused on the two constituents of SSHA, SSHAref determined from bottom pressure and SSHAbcb calculated from geopotential height referenced to the bottom. The peak variance of both SSHAbcb and SSHAref occurred in the energetic region between the Subantarctic Front and the Polar Front. The contribution of SSHAbcb to total SSHA variance was greater than 40% at all sites and averaged over all sites it was 73%. For most sites, high-frequency (> 1/20 cpd) SSHAbcb signals dominated total high-frequency variance. Aliasing of high-frequency signals resulting from 10-day altimeter sampling was assessed. The fraction of aliased energy at frequencies longer than 1/50 cpd for sites at and north of the Shackleton Fracture Zone approached 0.25 and approached 0.50 for southern sites. CPIES and mapped altimeter SSHA agreed well. The mean correlation coefficient was 0.82 and the mean RMS difference was 0.075 m. Correlations between CPIES and AVISO were notably poorer at the northern and southern boundaries. RMS differences increased as a function of CPIES high-frequency SSHA variance because the mapped altimetry product does not resolve these frequencies. |
format |
Text |
author |
Donohue, Kathleen A. Kennelly, Maureen A. Cutting, Amy |
author_facet |
Donohue, Kathleen A. Kennelly, Maureen A. Cutting, Amy |
author_sort |
Donohue, Kathleen A. |
title |
Sea surface height variability in drake passage |
title_short |
Sea surface height variability in drake passage |
title_full |
Sea surface height variability in drake passage |
title_fullStr |
Sea surface height variability in drake passage |
title_full_unstemmed |
Sea surface height variability in drake passage |
title_sort |
sea surface height variability in drake passage |
publisher |
DigitalCommons@URI |
publishDate |
2016 |
url |
https://digitalcommons.uri.edu/gsofacpubs/1214 https://doi.org/10.1175/JTECH-D-15-0249.1 |
long_lat |
ENVELOPE(-60.000,-60.000,-60.000,-60.000) |
geographic |
Antarctic Drake Passage Shackleton Shackleton Fracture Zone |
geographic_facet |
Antarctic Drake Passage Shackleton Shackleton Fracture Zone |
genre |
Antarc* Antarctic Drake Passage |
genre_facet |
Antarc* Antarctic Drake Passage |
op_source |
Graduate School of Oceanography Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/gsofacpubs/1214 doi:10.1175/JTECH-D-15-0249.1 https://doi.org/10.1175/JTECH-D-15-0249.1 |
op_doi |
https://doi.org/10.1175/JTECH-D-15-0249.1 |
container_title |
Journal of Atmospheric and Oceanic Technology |
container_volume |
33 |
container_issue |
4 |
container_start_page |
669 |
op_container_end_page |
683 |
_version_ |
1784259289187090432 |