The impact of the extreme Arctic sea ice conditions on weather and climate in Europe

The impact of the extreme Arctic sea ice

conditions on weather and climate in Europe

CT1/CT3 Meeting 22-23 April 2013 Hamburg

Lingling Suo; Yongqi GaoNansen Environmental and Remote Sensing Center, Bergen, Norway

Planned contribution to NACLIM

The northern sea surface temperatures (SST) and sea ice

distributions “strongly impact on weather and climate in Europe, determining precipitation patterns and

strengths, as well as changes in temperature and wind patterns.”

------ from NACLIM website

Model Experiments set upBlue: the 100 year mean in a present day simulation (CT0) which is a free coupled experiment performed by the Bergen Climate model with the external forcings fixed in 2000 year level.

By Dong Guo

Red: the last 20 year mean in a future projection experiment (FP0) which is a 120a free coupled experiment by BCM with the gradually increasing CO2 concentration from 367ppm to 992 ppm in the beginning100 years and the constant 992ppm CO2 concentration in the last 20 year. The other external forcings are fixed in 2000 year level

Black: the sea ice conditons interpolated from Blue and Red and used in our sensitivity experiments; Autumn – Sea ice free in Arctic;From winter to summer – same as present day:

Using Atmospere global climate model :

Control simulations (using the 100 year mean in CT0 as boundary conditions to force the model)

Sensitivity experiments (with sea ice removal and high sea surface temperature (the last 20a mean in FP0)

as boundary conditions during autumn in Arctic. In other regions and in other seasons in Arctic, the boundary conditions are the same as the control run.)

300 pairs for comparison. Each pairs last for one year.

The differences between control and sensitibity experiments are caused by extreme sea ice conditions and SST during autumn in

Arctic.

Model Experiments finished

Analysis on going:

Precipitation, Temperature changes and large scale atmosphere modulation when all sea ice is removed from the Arctic during the autumn.

The late response of weather and climate in Winter or Spring to the free sea ice Arctic during Autumn.

The teleconnection between Arctic sea ice conditions in Autumn and the mid-latitudes and tropics.

month

latit

ude

Snowfall

7 8 9 10 11 12 1 2 3 4 5 6 7

30

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70

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unit:

mm

/day

-0.4

-0.2

0

0.2

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0.6

month

latit

ude

Rainfall

7 8 9 10 11 12 1 2 3 4 5 6 7

30

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50

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unit:

mm

/day

-0.4

-0.2

0

0.2

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month

latit

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Snowfall + Rainfall

7 8 9 10 11 12 1 2 3 4 5 6 7

30

40

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unit:

mm

/day

-0.4

-0.2

0

0.2

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0.6

In general, the robutst reponses are mainly in autumn and early winter.

Local precipitation changes are most robust with more/less snowfall in far north of the Arctic/subpolar. The more rainfall is located in the region with less snowfall.

During this period, besides the local precipation changes in Arctic, there are teleconnection patterns in midlatitudes and subtropics where the anomalies can pass the 95% significance test.

The late rainfall response during the spring in mid latitude can also pass the 95% significance test.

Continue analysis on going

Try to construct the brige of the teleconnection between Arctic and midlatitide

To do

Thanks

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