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ROMFORSK-Program for romforskning

Upper ocean circulation from the Sentinel and Earth Explorer satellites - sensor synergy for advanced knowledge and understanding

Alternative title: Sirkulasjonen i de Nordiske havs øvre vannmasser - bedret forståelse gjennom synergieffekter fra Sentinel- og Explorer-satellittene

Awarded: NOK 4.8 mill.

Capitalising on new high-resolution satellite Earth observation datasets the project has focused on the study the upper ocean circulation in the Nordic Seas. This is associated with pole-ward transport of warm Atlantic Water to the high latitude and Arctic Ocean and is a key component in maintaining the relatively mild climate in northwestern Europe, the Barents Sea and Svalbard. The circulation also plays a key role for the biological productivity of the region. The results are clearly promising for regular use of satellite sensor synergy in studies of mesoscale dynamics and ocean circulation. It will have a central role in satellite remote sensing research at the Nansen Center. Regular access to ocean surface currents derived from SAR-based Doppler shift observations at fine spatial resolution (1-5km) will increase the use in coastal regions and lead to better model validation and assimilation in for instance the European Copernicus Marine Environment Monitoring Service. As such it will also expectedly advance the support to search and rescue operations, oil spill monitoring, marine offshore operations and ship routing. Beginning next year, Artem Moiseev shall work on a ESA funded study at the Nansens Center, where he will explore the methodology for use in studies of wave-current interaction. The method will also be made openly available and will as such stimulate to increased use of SAR-based surface current observations for studies of upper ocean dynamics and processes. Artem Moiseev will defend his PhD study in January 2021 and as such further promote the method and capability in the research community.

Resultat av prosjektet åpner nye muligheter for bruk av satellitt sensor synergi i studier av mesoskala dynamikk, og få en sentral rolle i videre forskning på Nansensenteret. Overflatestrøm fra SAR Doppler skift målingene øker både den romlige oppløsning og bruk i kystnære strøk, og vil bedre validering av havmodeller og assimilasjon i for eksempel den operative Europeiske Copernicus Marine Tjenesten. Det vil også styrke søk- og redningsoperasjoner, oljesøl håndtering og bedre informasjonstilgangen for marine operasjoner og skipsruting. Artem Moiseev skal jobbe på et nytt prosjekt ved Nansensenteret hvor metodikken skal anvendes i et ESA finansiert studie. Beregningsmetodikken vil også bli åpent tilgengelig og dermed bidra til økende bruk av SAR-basert strømobservasjoner for studier av havdynamikk og sirkulasjon. Artem Moiseev vil også ventelig forsvare sin doktorgrad i januar 2021, og gi ytterligere mulighet til å formidle metodikken og resultatene til en større forskningsgruppe.

In this project, we plan to take advantage of new and historic high-resolution satellite remote sensing datasets (i.e., synthetic aperture radar, altimetry, gravimetry, SST, ocean colour) to study the upper ocean circulation in the Nordic Seas. This is associated with pole-ward transport of warm Atlantic Water to the high latitude and Arctic Ocean and is a key component in maintaining the relatively mild climate in northwestern Europe, the Barents Sea and Svalbard. The circulation also plays a key role for the biological productivity of the region, which in turn is linked to fisheries. The new GOCE based geoid and mean dynamic topography (MDT) has improved the determination of the mean ocean circulation in the Nordic Seas at spatial scales of about 100-200 km, but fails to resolve strong and narrow topographically steered currents, as well as current fronts and eddies at the transition from mesoscale to sub-mesoscale (30-10 km). Hence, we are not able to fully exploit the available datasets (two decades of SSH observations) to study the temporal variability of these small-scale features. Recent scientific achievements using Doppler shift information have, however, demonstrated the capability to retrieve sea surface current from synthetic aperture radar (SAR). We plan to further develop the geophysical retrieval algorithms needed to partition wind, wave and current effects in the SAR Doppler shift to obtain mean monthly, seasonal, and yearly 2-dimensional sea surface velocity maps in the Nordic Seas from 2002 onwards. Combination of these with the new GOCE geoid and Sentinel-3 altimeter data will enable new improved estimates of the mean dynamic topography at short spatial scales. Analyses and research taking benefit of sensor synergy is thus expected to substantially advance the quality of the information and knowledge about the Nordic Seas upper ocean circulation.

Funding scheme:

ROMFORSK-Program for romforskning