Mooring observations of air-sea heat fluxes in two Subantarctic Mode Water formation regions Mooring observations of air-sea heat fluxes in two Subantarctic Mode Water formation regions
Abstract: Wintertime 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 an...
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ftcdlib:oai:escholarship.org:ark:/13030/qt7nx0d4gr 2023-11-05T03:45:12+01:00 Mooring observations of air-sea heat fluxes in two Subantarctic Mode Water formation regions 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 2020-01-01 application/pdf 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 Earth Sciences Oceanography Atmospheric Sciences Southern Ocean Atmosphere-ocean interaction Oceanic mixed layer Water masses storage Heat budgets fluxes Buoy observations Geomatic Engineering Meteorology & Atmospheric Sciences Climate change science article 2020 ftcdlib 2023-10-09T18:05:17Z Abstract: Wintertime 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 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Earth Sciences Oceanography Atmospheric Sciences Southern Ocean Atmosphere-ocean interaction Oceanic mixed layer Water masses storage Heat budgets fluxes Buoy observations Geomatic Engineering Meteorology & Atmospheric Sciences Climate change science |
spellingShingle |
Earth Sciences Oceanography Atmospheric Sciences Southern Ocean Atmosphere-ocean interaction Oceanic mixed layer Water masses storage Heat budgets fluxes Buoy observations Geomatic Engineering Meteorology & Atmospheric Sciences Climate change science 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 Mooring observations of air-sea heat fluxes in two Subantarctic Mode Water formation regions |
topic_facet |
Earth Sciences Oceanography Atmospheric Sciences Southern Ocean Atmosphere-ocean interaction Oceanic mixed layer Water masses storage Heat budgets fluxes Buoy observations Geomatic Engineering Meteorology & Atmospheric Sciences Climate change science |
description |
Abstract: Wintertime 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 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 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 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 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 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 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 |
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_ |
1781706766703132672 |