Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions
AbstractWintertime surface ocean heat loss is the key process driving the formation of Subantarctic Mode Water (SAMW), but there are few direct observations of heat fluxes, particularly during winter. The Ocean Observatories Initiative (OOI) Southern Ocean mooring in the southeast Pacific Ocean and...
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ftcdlib:oai:escholarship.org/ark:/13030/qt7nx0d4gr 2023-05-15T18:24:55+02:00 Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions Tamsitt, Veronica Cerovečki, Ivana Josey, Simon A Gille, Sarah T Schulz, Eric 2757 - 2777 2020-04-01 https://escholarship.org/uc/item/7nx0d4gr unknown eScholarship, University of California qt7nx0d4gr https://escholarship.org/uc/item/7nx0d4gr public Journal of Climate, vol 33, iss 7 Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences article 2020 ftcdlib 2021-02-18T15:13:49Z AbstractWintertime surface ocean heat loss is the key process driving the formation of Subantarctic Mode Water (SAMW), but there are few direct observations of heat fluxes, particularly during winter. The Ocean Observatories Initiative (OOI) Southern Ocean mooring in the southeast Pacific Ocean and the Southern Ocean Flux Station (SOFS) in the southeast Indian Ocean provide the first concurrent, multiyear time series of air–sea fluxes in the Southern Ocean from two key SAMW formation regions. In this work we compare drivers of wintertime heat loss and SAMW formation by comparing air–sea fluxes and mixed layers at these two mooring locations. A gridded Argo product and the ERA5 reanalysis product provide temporal and spatial context for the mooring observations. Turbulent ocean heat loss is on average 1.5 times larger in the southeast Indian (SOFS) than in the southeast Pacific (OOI), with stronger extreme heat flux events in the southeast Indian leading to larger cumulative winter ocean heat loss. Turbulent heat loss events in the southeast Indian (SOFS) occur in two atmospheric regimes (cold air from the south or dry air circulating via the north), while heat loss events in the southeast Pacific (OOI) occur in a single atmospheric regime (cold air from the south). On interannual time scales, wintertime anomalies in net heat flux and mixed layer depth (MLD) are often correlated at the two sites, particularly when wintertime MLDs are anomalously deep. This relationship is part of a larger basin-scale zonal dipole in heat flux and MLD anomalies present in both the Indian and Pacific basins, associated with anomalous meridional atmospheric circulation. Article in Journal/Newspaper Southern Ocean University of California: eScholarship Indian Pacific Southern Ocean |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences |
spellingShingle |
Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences Tamsitt, Veronica Cerovečki, Ivana Josey, Simon A Gille, Sarah T Schulz, Eric Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions |
topic_facet |
Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences |
description |
AbstractWintertime surface ocean heat loss is the key process driving the formation of Subantarctic Mode Water (SAMW), but there are few direct observations of heat fluxes, particularly during winter. The Ocean Observatories Initiative (OOI) Southern Ocean mooring in the southeast Pacific Ocean and the Southern Ocean Flux Station (SOFS) in the southeast Indian Ocean provide the first concurrent, multiyear time series of air–sea fluxes in the Southern Ocean from two key SAMW formation regions. In this work we compare drivers of wintertime heat loss and SAMW formation by comparing air–sea fluxes and mixed layers at these two mooring locations. A gridded Argo product and the ERA5 reanalysis product provide temporal and spatial context for the mooring observations. Turbulent ocean heat loss is on average 1.5 times larger in the southeast Indian (SOFS) than in the southeast Pacific (OOI), with stronger extreme heat flux events in the southeast Indian leading to larger cumulative winter ocean heat loss. Turbulent heat loss events in the southeast Indian (SOFS) occur in two atmospheric regimes (cold air from the south or dry air circulating via the north), while heat loss events in the southeast Pacific (OOI) occur in a single atmospheric regime (cold air from the south). On interannual time scales, wintertime anomalies in net heat flux and mixed layer depth (MLD) are often correlated at the two sites, particularly when wintertime MLDs are anomalously deep. This relationship is part of a larger basin-scale zonal dipole in heat flux and MLD anomalies present in both the Indian and Pacific basins, associated with anomalous meridional atmospheric circulation. |
format |
Article in Journal/Newspaper |
author |
Tamsitt, Veronica Cerovečki, Ivana Josey, Simon A Gille, Sarah T Schulz, Eric |
author_facet |
Tamsitt, Veronica Cerovečki, Ivana Josey, Simon A Gille, Sarah T Schulz, Eric |
author_sort |
Tamsitt, Veronica |
title |
Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions |
title_short |
Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions |
title_full |
Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions |
title_fullStr |
Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions |
title_full_unstemmed |
Mooring Observations of Air–Sea Heat Fluxes in Two Subantarctic Mode Water Formation Regions |
title_sort |
mooring observations of air–sea heat fluxes in two subantarctic mode water formation regions |
publisher |
eScholarship, University of California |
publishDate |
2020 |
url |
https://escholarship.org/uc/item/7nx0d4gr |
op_coverage |
2757 - 2777 |
geographic |
Indian Pacific Southern Ocean |
geographic_facet |
Indian Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Journal of Climate, vol 33, iss 7 |
op_relation |
qt7nx0d4gr https://escholarship.org/uc/item/7nx0d4gr |
op_rights |
public |
_version_ |
1766205957800460288 |