Atlantic water transports to the Arctic and their impact on sea ice

C. Herbaut, M.-N. Houssais, A.-C. Blaizot and S. Close

LOCEAN, UPMC

Atlantic Water pathways in the Arctic

Polyakov et al., 2012

Barents Sea

Sea ice extent

Surface circulation

Northern mode and Eastern mode

Winter Sea Ice Concentration (SSMR - SSM-I)

SIC standard deviation (1979-2011)

Northern ModeEastern Mode

Sea ice area

R= 0.38

Northern Mode Index Eastern Mode Index

Regression of the SIC on Northern and Eastern modes

Northern Mode Northerly winds

Eastern Mode Easterly winds

Wind stress Sea ice production

ORCA025 Arctic-Atlantic configuration ERA-I forcing (1979-2011)

Lag 0

Ocean impact on the Northern mode

Climatology

Regression on the Northern mode

Correlation BSO heat transport on Northern Mode

Lag 0

OuflowInflowNet

Regression of temperature at 110 meters on the northern mode at lag -1 year

Correlation BSO heat content on Northern ModeLag -1 year

Ocean heat contentDivergence of heat transportSurface heat flux

Reemergence of the AW temperature anomalies

Regression of OND SST on the Northern Mode

Regression of winter SLP on October SST

Impact of the SST anomalies on the atmosphere (and SIC) ?

Atlantic Water pathways in the Arctic

Observations

LongitudeLongitude

Model

FramStrait

Temperature

Fram Strait

Eof1 temperature 38% Eof1 heat transport 48% Eof1 Velocity 34%

Correlation:Velocity – Heat transport = 0.88Temperature - Heat transport = 0.50

Atlantic Water proprerties in Fram Strait in winter (JFM)

TemperatureVelocityHeat transport

PC1s

Atlantic Water circulation

Regression on PC1 of velocity at Fram Strait

Currents at 230 meters JFM SLP DJF

• Cyclonic circulation over the Nordic Seas + Arctic Ocean• Arctic Oscillation

Regression the current at 230 meters on PC2 of velocity in the WSC

localized circulation in the Barents Sea

Lag -1 year Lag 0

Regression on PC1 of temperature in Fram Strait

• Temperature anomalies over the Barents Sea + Fram Strait Branch

Atlantic Water temperature (230 m)

2008

Constant passive tracer sources : • BSO• Fram Strait (0-800 m)

Distribution of passive tracers at 230 meters

Fram Strait Branch Barents Sea Branch

Interannual variability at Kola Section

off Laptev Sea

Seasonal variability if the fram Strait Branch

ModelObservations

North of Svalbard

Variability of the Atlantic Water

Vertical distribution of passive tracers and temperature

Off Laptev Sea

2008

Fram Strait Branch Barents Sea Branch

• Core of the FSB tracer coïncides with the temperature maximum

• Maximum of the BSB tracer along the coast

Hovmoeller of Temperature along the slope of the Eurasien Basin

• Propagation of two strong warming events

• Strong decrease of temperature and tracer east of St Anna Trough

Temperature

Correlation: 0.48

FSB Tracer

West of St Anna Trough

Correlation: 0.78

Off Laptev Sea

BSB Tracer

Correlation: -0.78

Variability of the temperature in the core of the Atlantic branch linked with the variability of the exchange between the Barents and Fram Strait Branches.

Impact of the temperature variability in the FSB on sea ice properties

Climatological sea ice melt in winter (cm/d)

Regression of the sea ice melt in winter on PC1 of T in Fram Strait

• Hints of influence north of the Barents Sea

Next• Analyse the covariability of the AW branches in FS and BS• Diagnose ocean vertical heat fluxes and their impact on sea ice• Analyse the atmospheric modes linked to sea ice/SST variability• Other seasons …

The research leading to these results has received funding from the European Union 7th Framework Programme (FP7 2007-2013), under grant agreement n.308299NACLIM www.naclim.eu