Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations
Surface water partial pressure of CO2 (pCO2) variations in Drake Passage are examined using decade-long underway shipboard measurements. North of the Polar Front (PF), the observed pCO2 shows a seasonal cycle that peaks annually in August and dissolved inorganic carbon (DIC)-forced variations are si...
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ftcdlib:oai:escholarship.org:ark:/13030/qt0s97f2rp 2023-06-11T04:11:19+02:00 Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations Jiang, ChuanLi Gille, Sarah T Sprintall, Janet Sweeney, Colm 76 - 100 2014-01-01 application/pdf https://escholarship.org/uc/item/0s97f2rp unknown eScholarship, University of California qt0s97f2rp https://escholarship.org/uc/item/0s97f2rp public Journal of Climate, vol 27, iss 1 Climate Action Southern Ocean Ocean circulation Air-sea interaction Carbon cycle Climate models Model evaluation performance Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences article 2014 ftcdlib 2023-05-29T17:59:39Z Surface water partial pressure of CO2 (pCO2) variations in Drake Passage are examined using decade-long underway shipboard measurements. North of the Polar Front (PF), the observed pCO2 shows a seasonal cycle that peaks annually in August and dissolved inorganic carbon (DIC)-forced variations are significant. Just south of the PF, pCO2 shows a small seasonal cycle that peaks annually in February, reflecting the opposing effects of changes in SST and DIC in the surface waters. At the PF, the wintertime pCO2 is nearly in equilibrium with the atmosphere, leading to a small sea-to-air CO2 flux. These observations are used to evaluate eight available Coupled Model Intercomparison Project, phase 5 (CMIP5), Earth system models (ESMs). Six ESMs reproduce the observed annual-mean pCO2 values averaged over the Drake Passage region. However, the model amplitude of the pCO2 seasonal cycle exceeds the observed amplitude of the pCO2 seasonal cycle because of the model biases in SST and surface DIC. North of the PF, deep winter mixed layers play a larger role in pCO2 variations in the models than they do in observations. Four ESMs show elevated wintertime pCO2 near the PF, causing a significant sea-to-air CO2 flux. Wintertime winds in these models are generally stronger than the satellite-derived winds. This not only magnifies the sea-to-air CO2 flux but also upwells DIC-rich water to the surface and drives strong equatorward Ekman currents. These strong model currents likely advect the upwelled DIC farther equatorward, as strong stratification in the models precludes subduction below the mixed layer. © 2014 American Meteorological Society. Article in Journal/Newspaper Drake Passage Southern Ocean University of California: eScholarship Drake Passage Southern Ocean |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action Southern Ocean Ocean circulation Air-sea interaction Carbon cycle Climate models Model evaluation performance Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences |
spellingShingle |
Climate Action Southern Ocean Ocean circulation Air-sea interaction Carbon cycle Climate models Model evaluation performance Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences Jiang, ChuanLi Gille, Sarah T Sprintall, Janet Sweeney, Colm Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations |
topic_facet |
Climate Action Southern Ocean Ocean circulation Air-sea interaction Carbon cycle Climate models Model evaluation performance Atmospheric Sciences Oceanography Geomatic Engineering Meteorology & Atmospheric Sciences |
description |
Surface water partial pressure of CO2 (pCO2) variations in Drake Passage are examined using decade-long underway shipboard measurements. North of the Polar Front (PF), the observed pCO2 shows a seasonal cycle that peaks annually in August and dissolved inorganic carbon (DIC)-forced variations are significant. Just south of the PF, pCO2 shows a small seasonal cycle that peaks annually in February, reflecting the opposing effects of changes in SST and DIC in the surface waters. At the PF, the wintertime pCO2 is nearly in equilibrium with the atmosphere, leading to a small sea-to-air CO2 flux. These observations are used to evaluate eight available Coupled Model Intercomparison Project, phase 5 (CMIP5), Earth system models (ESMs). Six ESMs reproduce the observed annual-mean pCO2 values averaged over the Drake Passage region. However, the model amplitude of the pCO2 seasonal cycle exceeds the observed amplitude of the pCO2 seasonal cycle because of the model biases in SST and surface DIC. North of the PF, deep winter mixed layers play a larger role in pCO2 variations in the models than they do in observations. Four ESMs show elevated wintertime pCO2 near the PF, causing a significant sea-to-air CO2 flux. Wintertime winds in these models are generally stronger than the satellite-derived winds. This not only magnifies the sea-to-air CO2 flux but also upwells DIC-rich water to the surface and drives strong equatorward Ekman currents. These strong model currents likely advect the upwelled DIC farther equatorward, as strong stratification in the models precludes subduction below the mixed layer. © 2014 American Meteorological Society. |
format |
Article in Journal/Newspaper |
author |
Jiang, ChuanLi Gille, Sarah T Sprintall, Janet Sweeney, Colm |
author_facet |
Jiang, ChuanLi Gille, Sarah T Sprintall, Janet Sweeney, Colm |
author_sort |
Jiang, ChuanLi |
title |
Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations |
title_short |
Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations |
title_full |
Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations |
title_fullStr |
Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations |
title_full_unstemmed |
Drake Passage Oceanic pCO2: Evaluating CMIP5 Coupled Carbon–Climate Models Using in situ Observations |
title_sort |
drake passage oceanic pco2: evaluating cmip5 coupled carbon–climate models using in situ observations |
publisher |
eScholarship, University of California |
publishDate |
2014 |
url |
https://escholarship.org/uc/item/0s97f2rp |
op_coverage |
76 - 100 |
geographic |
Drake Passage Southern Ocean |
geographic_facet |
Drake Passage Southern Ocean |
genre |
Drake Passage Southern Ocean |
genre_facet |
Drake Passage Southern Ocean |
op_source |
Journal of Climate, vol 27, iss 1 |
op_relation |
qt0s97f2rp https://escholarship.org/uc/item/0s97f2rp |
op_rights |
public |
_version_ |
1768386277259870208 |