Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic
A reanalysis of the North Atlantic spring bloom in 2007 was produced using the real-time analysis from the TOPAZ North Atlantic and Arctic forecasting system. The TOPAZ system uses a hybrid coordinate general circulation ocean model and assimilates physical observations: sea surface anomalies, sea s...
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ftdoajarticles:oai:doaj.org/article:0e59dd74498449e5b7f13664463e025c 2023-05-15T14:58:03+02:00 Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic A. Samuelsen L. Bertino C. Hansen 2009-12-01T00:00:00Z https://doaj.org/article/0e59dd74498449e5b7f13664463e025c EN eng Copernicus Publications http://www.ocean-sci.net/5/635/2009/os-5-635-2009.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 1812-0784 1812-0792 https://doaj.org/article/0e59dd74498449e5b7f13664463e025c Ocean Science, Vol 5, Iss 4, Pp 635-647 (2009) Geography. Anthropology. Recreation G Environmental sciences GE1-350 article 2009 ftdoajarticles 2022-12-31T02:52:31Z A reanalysis of the North Atlantic spring bloom in 2007 was produced using the real-time analysis from the TOPAZ North Atlantic and Arctic forecasting system. The TOPAZ system uses a hybrid coordinate general circulation ocean model and assimilates physical observations: sea surface anomalies, sea surface temperatures, and sea-ice concentrations using the Ensemble Kalman Filter. This ocean model was coupled to an ecosystem model, NORWECOM (Norwegian Ecological Model System), and the TOPAZ-NORWECOM coupled model was run throughout the spring and summer of 2007. The ecosystem model was run online, restarting from analyzed physical fields (result after data assimilation) every 7 days. Biological variables were not assimilated in the model. The main purpose of the study was to investigate the impact of physical data assimilation on the ecosystem model. This was determined by comparing the results to those from a model without assimilation of physical data. The regions of focus are the North Atlantic and the Arctic Ocean. Assimilation of physical variables does not affect the results from the ecosystem model significantly. The differences between the weekly mean values of chlorophyll are normally within 5–10% during the summer months, and the maximum difference of ~20% occurs in the Arctic, also during summer. Special attention was paid to the nutrient input from the North Atlantic to the Nordic Seas and the impact of ice-assimilation on the ecosystem. The ice-assimilation increased the phytoplankton concentration: because there was less ice in the assimilation run, this increased both the mixing of nutrients during winter and the area where production could occur during summer. The forecast was also compared to remotely sensed chlorophyll, climatological nutrients, and in-situ data. The results show that the model reproduces a realistic annual cycle, but the chlorophyll concentrations tend to be between 0.1 and 1.0 mg chl a /m 3 too low during winter and spring and 1–2 mg chl a /m 3 too high during summer. Surface ... Article in Journal/Newspaper Arctic Arctic Ocean Nordic Seas North Atlantic Phytoplankton Sea ice Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
spellingShingle |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 A. Samuelsen L. Bertino C. Hansen Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic |
topic_facet |
Geography. Anthropology. Recreation G Environmental sciences GE1-350 |
description |
A reanalysis of the North Atlantic spring bloom in 2007 was produced using the real-time analysis from the TOPAZ North Atlantic and Arctic forecasting system. The TOPAZ system uses a hybrid coordinate general circulation ocean model and assimilates physical observations: sea surface anomalies, sea surface temperatures, and sea-ice concentrations using the Ensemble Kalman Filter. This ocean model was coupled to an ecosystem model, NORWECOM (Norwegian Ecological Model System), and the TOPAZ-NORWECOM coupled model was run throughout the spring and summer of 2007. The ecosystem model was run online, restarting from analyzed physical fields (result after data assimilation) every 7 days. Biological variables were not assimilated in the model. The main purpose of the study was to investigate the impact of physical data assimilation on the ecosystem model. This was determined by comparing the results to those from a model without assimilation of physical data. The regions of focus are the North Atlantic and the Arctic Ocean. Assimilation of physical variables does not affect the results from the ecosystem model significantly. The differences between the weekly mean values of chlorophyll are normally within 5–10% during the summer months, and the maximum difference of ~20% occurs in the Arctic, also during summer. Special attention was paid to the nutrient input from the North Atlantic to the Nordic Seas and the impact of ice-assimilation on the ecosystem. The ice-assimilation increased the phytoplankton concentration: because there was less ice in the assimilation run, this increased both the mixing of nutrients during winter and the area where production could occur during summer. The forecast was also compared to remotely sensed chlorophyll, climatological nutrients, and in-situ data. The results show that the model reproduces a realistic annual cycle, but the chlorophyll concentrations tend to be between 0.1 and 1.0 mg chl a /m 3 too low during winter and spring and 1–2 mg chl a /m 3 too high during summer. Surface ... |
format |
Article in Journal/Newspaper |
author |
A. Samuelsen L. Bertino C. Hansen |
author_facet |
A. Samuelsen L. Bertino C. Hansen |
author_sort |
A. Samuelsen |
title |
Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic |
title_short |
Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic |
title_full |
Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic |
title_fullStr |
Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic |
title_full_unstemmed |
Impact of data assimilation of physical variables on the spring bloom from TOPAZ operational runs in the North Atlantic |
title_sort |
impact of data assimilation of physical variables on the spring bloom from topaz operational runs in the north atlantic |
publisher |
Copernicus Publications |
publishDate |
2009 |
url |
https://doaj.org/article/0e59dd74498449e5b7f13664463e025c |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Nordic Seas North Atlantic Phytoplankton Sea ice |
genre_facet |
Arctic Arctic Ocean Nordic Seas North Atlantic Phytoplankton Sea ice |
op_source |
Ocean Science, Vol 5, Iss 4, Pp 635-647 (2009) |
op_relation |
http://www.ocean-sci.net/5/635/2009/os-5-635-2009.pdf https://doaj.org/toc/1812-0784 https://doaj.org/toc/1812-0792 1812-0784 1812-0792 https://doaj.org/article/0e59dd74498449e5b7f13664463e025c |
_version_ |
1766330133563572224 |