Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current
International audience Like many western boundary currents, the East Australian Current (EAC) extension is projected to get stronger and warmer in the future. The CMIP5 multimodel mean (MMM) projection suggests up to 5°C of warming under an RCP85 scenario by 2100. Previous studies employed Sverdrup...
Published in: | Journal of Geophysical Research: Oceans |
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Online Access: | https://hal.science/hal-03001068 https://hal.science/hal-03001068/document https://hal.science/hal-03001068/file/2019JC015889.pdf https://doi.org/10.1029/2019JC015889 |
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ftinsu:oai:HAL:hal-03001068v1 2024-04-28T08:39:43+00:00 Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current Bull, Christopher Kiss, Andrew Gupta, Alex Sen Jourdain, Nicolas Argüeso, Daniel Di Luca, Alejandro Sérazin, Guillaume Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) 2020-07 https://hal.science/hal-03001068 https://hal.science/hal-03001068/document https://hal.science/hal-03001068/file/2019JC015889.pdf https://doi.org/10.1029/2019JC015889 en eng HAL CCSD Wiley-Blackwell info:eu-repo/semantics/altIdentifier/doi/10.1029/2019JC015889 hal-03001068 https://hal.science/hal-03001068 https://hal.science/hal-03001068/document https://hal.science/hal-03001068/file/2019JC015889.pdf doi:10.1029/2019JC015889 info:eu-repo/semantics/OpenAccess ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.science/hal-03001068 Journal of Geophysical Research. Oceans, 2020, 125 (7), ⟨10.1029/2019JC015889⟩ [SDU.OTHER]Sciences of the Universe [physics]/Other [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2020 ftinsu https://doi.org/10.1029/2019JC015889 2024-04-05T00:37:31Z International audience Like many western boundary currents, the East Australian Current (EAC) extension is projected to get stronger and warmer in the future. The CMIP5 multimodel mean (MMM) projection suggests up to 5°C of warming under an RCP85 scenario by 2100. Previous studies employed Sverdrup balance to associate a trend in basin wide zonally integrated wind stress curl (resulting from the multidecadal poleward intensification in the westerly winds over the Southern Ocean) with enhanced transport in the EAC extension. Possible regional drivers are yet to be considered. Here we introduce the NEMO-OASIS-WRF coupled regional climate model as a framework to improve our understanding of CMIP5 projections. We analyze a hierarchy of simulations in which the regional atmosphere and ocean circulations are allowed to freely evolve subject to boundary conditions that represent present-day and CMIP5 RCP8.5 climate change anomalies. Evaluation of the historical simulation shows an EAC extension that is stronger than similar ocean-only models and observations. This bias is not explained by a linear response to differences in wind stress. The climate change simulations show that regional atmospheric CMIP5 MMM anomalies drive 73% of the projected 12 Sv increase in EAC extension transport whereas the remote ocean boundary conditions and regional radiative forcing (greenhouse gases within the domain) play a smaller role. The importance of regional changes in wind stress curl in driving the enhanced EAC extension is consistent with linear theory where the NEMO-OASIS-WRF response is closer to linear transport estimates compared to the CMIP5 MMM. Plain Language Summary In recent decades, enhanced warming, severe marine heatwaves, and increased transport by the East Australian Current have led to the invasion of nonnative species and the destruction of kelp forests east of Tasmania. The East Australian Current extension is projected to get stronger and warmer in the future. We seek to better understand coupled climate model ... Article in Journal/Newspaper Southern Ocean Institut national des sciences de l'Univers: HAL-INSU Journal of Geophysical Research: Oceans 125 7 |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU.OTHER]Sciences of the Universe [physics]/Other [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.OTHER]Sciences of the Universe [physics]/Other [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Bull, Christopher Kiss, Andrew Gupta, Alex Sen Jourdain, Nicolas Argüeso, Daniel Di Luca, Alejandro Sérazin, Guillaume Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current |
topic_facet |
[SDU.OTHER]Sciences of the Universe [physics]/Other [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience Like many western boundary currents, the East Australian Current (EAC) extension is projected to get stronger and warmer in the future. The CMIP5 multimodel mean (MMM) projection suggests up to 5°C of warming under an RCP85 scenario by 2100. Previous studies employed Sverdrup balance to associate a trend in basin wide zonally integrated wind stress curl (resulting from the multidecadal poleward intensification in the westerly winds over the Southern Ocean) with enhanced transport in the EAC extension. Possible regional drivers are yet to be considered. Here we introduce the NEMO-OASIS-WRF coupled regional climate model as a framework to improve our understanding of CMIP5 projections. We analyze a hierarchy of simulations in which the regional atmosphere and ocean circulations are allowed to freely evolve subject to boundary conditions that represent present-day and CMIP5 RCP8.5 climate change anomalies. Evaluation of the historical simulation shows an EAC extension that is stronger than similar ocean-only models and observations. This bias is not explained by a linear response to differences in wind stress. The climate change simulations show that regional atmospheric CMIP5 MMM anomalies drive 73% of the projected 12 Sv increase in EAC extension transport whereas the remote ocean boundary conditions and regional radiative forcing (greenhouse gases within the domain) play a smaller role. The importance of regional changes in wind stress curl in driving the enhanced EAC extension is consistent with linear theory where the NEMO-OASIS-WRF response is closer to linear transport estimates compared to the CMIP5 MMM. Plain Language Summary In recent decades, enhanced warming, severe marine heatwaves, and increased transport by the East Australian Current have led to the invasion of nonnative species and the destruction of kelp forests east of Tasmania. The East Australian Current extension is projected to get stronger and warmer in the future. We seek to better understand coupled climate model ... |
author2 |
Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) |
format |
Article in Journal/Newspaper |
author |
Bull, Christopher Kiss, Andrew Gupta, Alex Sen Jourdain, Nicolas Argüeso, Daniel Di Luca, Alejandro Sérazin, Guillaume |
author_facet |
Bull, Christopher Kiss, Andrew Gupta, Alex Sen Jourdain, Nicolas Argüeso, Daniel Di Luca, Alejandro Sérazin, Guillaume |
author_sort |
Bull, Christopher |
title |
Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current |
title_short |
Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current |
title_full |
Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current |
title_fullStr |
Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current |
title_full_unstemmed |
Regional Versus Remote Atmosphere‐Ocean Drivers of the Rapid Projected Intensification of the East Australian Current |
title_sort |
regional versus remote atmosphere‐ocean drivers of the rapid projected intensification of the east australian current |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-03001068 https://hal.science/hal-03001068/document https://hal.science/hal-03001068/file/2019JC015889.pdf https://doi.org/10.1029/2019JC015889 |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.science/hal-03001068 Journal of Geophysical Research. Oceans, 2020, 125 (7), ⟨10.1029/2019JC015889⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2019JC015889 hal-03001068 https://hal.science/hal-03001068 https://hal.science/hal-03001068/document https://hal.science/hal-03001068/file/2019JC015889.pdf doi:10.1029/2019JC015889 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2019JC015889 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
125 |
container_issue |
7 |
_version_ |
1797570631918682112 |