loss of sea ice in the svalbard barents sea region - … · loss of sea ice in the svalbard –...

Loss of sea ice in the Svalbard –

Barents Sea region

Ingrid H. Onarheim1 T. Eldevik1, M. Årthun1, L.H. Smedsrud1, R.B. Ingvaldsen2

1 Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research, Bergen, Norway 2 Institute of Marine Research, Bergen, Norway

http://svs.gsfc.nasa.gov/

Sea ice area in September

2012

2007 2015

Are

a (

10

6 k

m2)

Reduced by ~50% since 1979

http://nsidc.org/arcticseaicenews/

September March

1979-2013

Trends in sea ice concentration

Helland-Hansen and Nansen, 1909: “… the quantity of ice in spring is dependent on the quantity of heat contained in the water-masses of the Barents Sea during winter…”

The Svalbard - Barents Sea region

1901 1902 1903 1904 1905

Atlantic Water

- - - Cod

~68ºN

~62ºN

Helland-Hansen and Nansen, 1909: “… the quantity of ice in spring is dependent on the quantity of heat contained in the water-masses of the Barents Sea during winter…”

The Svalbard - Barents Sea region

Fish communities

2004 2012

Arctic community Central community Atlantic community

Fossheim et al. (2015) Nature Climate Change

Shtokman

Onarheim, I.H., L.H. Smedsrud, R.B. Ingvaldsen, and F. Nilsen (2014). Loss of sea ice during winter north of Svalbard. Tellus A, 66, 23933

Loss of sea ice during winter north of Svalbard

NSIDC

Seasonal variations in sea ice concentration

NSIDC

Seasonal variations in sea ice concentration

1980s 1990s 2000s 2010 2011 2012

NSIDC

40% ice concentration

Loss of sea ice in winter since the 1980s

r=0.5

NSIDC ERA-Interim

• No trend in wind • Impact on interannual

variability

Ice concentration and wind (DJFM)

+1°C

+7°C

Extra AW heat: • melting of sea ice • atmospheric warming • warming of ambient

waters • carry on into the Arctic

Ocean

Increased AW heat content > 30 times increased atmospheric heat content

Ice concentration, AW temperature and air temperature (DJFM)

Onarheim, I.H., T. Eldevik, M. Årthun, R.B. Ingvaldsen, and L.H. Smedsrud (2015), Skillful prediction of Barents Sea ice cover, Geophys. Res. Lett., 42, 5364–5371,

Skillful prediction of Barents Sea ice cover

ice

atmosphere

Atlantic water Arctic water

1981

Barents Sea

Norwegian

Sea

Årthun et al., J. Clim., 2012; Onarheim et al., GRL, 2015

ice

2010

Barents Sea

Atlantic water Arctic water

Norwegian

Sea

atmosphere

Årthun et al., J. Clim., 2012; Onarheim et al., GRL, 2015

ice

Barents Sea

Atlantic water Arctic water

Norwegian

Sea

atmosphere

Årthun et al., J. Clim., 2012; Onarheim et al., GRL, 2015

Aice

Barents Sea

Atlantic water Arctic water

HT

HF

dHC/dt = -HF + HT

-dAice/dt = aAice + bHT

Norwegian

Sea

atmosphere

Årthun et al., J. Clim., 2012; Onarheim et al., GRL, 2015

Aice

Barents Sea

Atlantic water Arctic water

HT

HF

dHC/dt = -HF + HT

-dAice/dt = aAice + bHT r = 0.84

sign: 31/35

Årthun et al., J. Clim., 2012; Onarheim et al., GRL, 2015

Norwegian

Sea

atmosphere

Aice

Barents Sea

Atlantic water Arctic water

HT

HF

dHC/dt = -HF + HT

-dAice/dt = aAice + bHT + gV r = 0.92

Årthun et al., J. Clim., 2012; Onarheim et al., GRL, 2015

+ wind

Norwegian

Sea

atmosphere

The Barents Sea ice edge

Dagens Næringsliv 8 August

Questions?

Ingrid.Onarheim@gfi.uib.no

Barents Sea ice area

Prognostic framework

29

HF

HT

Aice

HT: heat transport HF: heat flux HC: heat content

HC

𝑑𝐻𝐶

𝑑𝑡= 𝐻𝑇 − 𝐻𝐹

Atlantic domain Arctic domain

?

𝑑𝐴𝑖𝑐𝑒

𝑑𝑡= −

𝑞0

ℎ𝑐0𝐴𝑖𝑐𝑒 −

1

ℎ𝑐0𝐻𝑇

𝐻𝐶 = −ℎ𝑐0𝐴𝑖𝑐𝑒, 𝐻𝐹 = −𝑞0𝐴𝑖𝑐𝑒

ℎ𝑐0 =𝑠𝑡𝑑 𝐻𝐶

𝑠𝑡𝑑 𝐴𝑖𝑐𝑒, 𝑞0 =

𝑠𝑡𝑑 𝐻𝐹

𝑠𝑡𝑑 𝐴𝑖𝑐𝑒

Årthun et al. (2012)

March

Trends in sea ice concentration

Barents Sea explains 92% of

winter variance in Arctic sea ice