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