O_Skagseth-T_Furevik-R_Ingvaldsen-H_Loeng-KA_Mork-KA_Orvik-V_Ozhigin.pdf (1.554Mb)

(1)

Transports and propagation of anomalies in the Norwegian

and Barents Seas

Øystein Skagseth, Randi

Ingvaldsen, Harald Loeng,

Tore Furevik, Kjell Arne Mork,

Kjell A Orvik, Vladimir Ozhigin

(2)

Map of the area

• Bruk systemfonten Arial

• Skriften skal være sort.

Outline

• Structure

• Forcing

• Decadal to inter-annual

• Multi-decadal

• Conclusion

(3)

Structure of Atlantic water

Svinøy section

Width~40km Velocity~30cm/s

Skagseth et al. 2007 350 0

0

1000

velocity

Barents Sea Opening

Width~200km Velocity~5cm/s

0

500

400 0

velocity

(4)

Atmospheric forcing and currents

Vsvinøy

VBSO

Simul. weak currents; < 1std Simul. strong currents; > 1std

mslp

Note! Case when the currents are in opposite phase

(5)

Correlation (r)

Relations: Svinøy and Barents Sea Opening

Temperature: Max corr. at 2year lag,

Skagseth et al. 2007

T_BSO(t)

T_Svinøy(t+2year)

Temperature

Velocity: Max corr. at zero lag suggest similar atm. systems affect both sites, but moderate r due to diff. regional effect of this forcing?

Prediction

(6)

Heat flux from current meters

Mean fluxes:

Svinøy (slope)=4.3Sv/123TW BSO=1.8Sv/48TW

(7)

Inter-annual variations in Atlantic water

* The period of curr.met.

1995 are in prolongation of a warm period, i.e. flux estimates are higer than the long-term mean

(8)

Sutton et al., 2005

Multidecadal variations

Atlantic Multidecadal Oscillation - index: T variation over Atl. Ocean between 0-60degN

Note detrended data

(9)

Multidecadal variations (2)

Barents Sea T variations follow the large scale variations in the Atlantic Ocean on decadal time scale

Atlantic Multidecadal Oscillation: T variation over Atl. Ocean between 0-60^oN

Kola section

AMO-index

(10)

Concluding remarks

- Lagged relations for hydrography

- A relatively weak put positive relation between fluxes in the southern Norw. – and the Barents Seas

- Long-term change in hydrography, warming since the 1970’ies, effect on the heat flux to Barents Sea.

- The multi-decadal changes in Barents follow that of the Atlantic Ocean

- For the present climate the oceanic fluxes in the Norw. Sea and the Barents Sea tend to follow, but this can be very sensitive to changes in the atm. Circulation (e.g. the storm tracks).