The autumn-winter atmospheric
response to the projected autumn
Arctic sea ice free conditions
Lingling SUO, Yongqi GAO, Dong Guo, Jiping Liu,
Huijun Wang, and Ola M. JOHANNESSEN
Motivation
Large Uncertanties !
the winter atmosphere circulaiton response to the autumn sea ice retreat
•Negative AO patterns
2
September sea ice extent (km )
Francis et al., 2009; Liu et al., 2012; Cohen et al., 2012; Li and Wang, 2013
•Positive AO patterns
Screen et al., 2013a
•Not classical AO patterns
1
x 10
6
0
-1
-2
-3
-4
1970
1980
1990
2000
2010
Blüthgen et al., 2012; Screen et al., 2013a; Screen et al., 2013a
Note: Liu etal, 2012 and Screen etal, 2013a obtained the contrary
results by the utilization of the same model and different ensembles.
Implying the importance of the internal variability!
2020
Strong snowstorms and coldness hit Europe!
Possbile link between Arctic sea ice
reteat and the winter climate
(snowcover, coldness ……) in
northern hemisphere proposed by
previous studies (Liu etal, 2012; Yang and
Christensen, 2012; Francis and Vavrus, 2012; etal);
Blue Arctic could appear earlier than expected
What’s the impact on the climate? Not clear…
More intense and easier detectable response?
Approach:
Using Atmosphere global climate model :
Control simulations (CONT) (300 one-year-lasting members )
using the 100 year mean in pre-performed present day simulation by BCM as boundary
conditions to force the model.
Sensitivity experiments (SENS) (300 one-year-lasting members )
with sea ice removal and future projected SST associated with Arctic sea ice free as boundary
conditions during autumn in Arctic. In other regions during the whole year and in Arctic during the
other seasons, the boundary conditions are the same as the control run.
The differences between control and sensitibity experiments
are caused by autumn extreme sea ice conditions and
associated SST in Arctic.
Using ERA Interim for comparison with the model results.
Dailiy sea ice area variation in Control (CONT) and sensitivity (SENS) experiment
sea ice concentration changes
between SENS and CONT
Sep-Oct mean
Nov
Dec
Model validation
Control
ERAI
Winter SLP
Winter precipitation
Winter SAT
300 ensembles mean
1979-2000mean
SAT
10
0
unit: C
5
-5
-10
Similar patterns in Oct and Nov. Oct-Nov mean patterns are shown.
The significant response basiclly occuly the mid-high latitudes.
snowfall
PW
5
2
-0.5
rainfall
0.5
-0.5
unit: mm/day
0
0
unit: kg/m
0
unit: mm/day
0.5
-5
Similar patterns in Oct and Nov. Oct-Nov mean patterns are shown.
The significant response basiclly occuly the mid-high latitudes.
Monthly variation of the zonal mean response
Fractional significant signals, No robust negative or positive AO patterns.
Significant response in the continential region occupy the Europe
Fractional significant signals, No robust negative or positive AO patterns.
Significant response in the continential region occupy the Europe
SLP anomalies (shaded) and 500hPa wave flux anomaliy (vector)
75  SLP (Model)
N
60 
N
45 
N
0
75  SAT (Model)
N
15 
-4
60 
N
 E
0
E 30  E 45 E 6

-2
0
2
unit: hPa
75  PW (Model)
N
4
60 
N
45 
N
45 
N
0
0
15 


E
15
E 30  E 45 E 60
-2
0
unit: C
2
-1



E 30 E 45 E 60
0
E
1
2
unit: kg/m
75  Snowfall (Model)
N
0.5
unit: mm/day
60 
N
0
45 
N
0
15 

E

30 E
60

45 E
Rainfall
-0.5
Total Precipitation
75 
N
75 
N
60 
N
60 
N
45 
N
0
E
45 
N
15 



E 30 E 45 E 60
-0.5
0
E
0
unit: mm/day
15 



E 30 E 45 E 60
0.5
E
Conclusion
1) The autumn Arctic sea ice free can cause significant local warming,
atmospheric precipitable water increase and total precipitation increase
during the autumn.
The SLP over the Arctic Ocean shows negative anomalies while there are
three positive anomaly centers over the north west America, the Europe
and the north of the East Asia. Which looks more like 2-3 zonal waves
pattern rather than the classical AO pattern.
2) The autumn atmospheric response can not persist during the middle and
late winter season. The significant winter SLP response is much more
local. The robust SLP response basiclly occupy the Europe.
2) The late winter low SLP anomaly over the East Europe could bring the
intense snowfall locally and the warming over the mid-Asia.
Ongoing Work
In order to compare with the internal variability
• The signal to noise ratio of the atmospheric
response
• For specific response interested, the density
distribution of 300 members in CONT and SENS. For
example, the SLP and snowfall over the East Europe.
Future Plan
Parallel experiments using ocean-atmosphere oupled model have done.
What are the atmospheric responses when the
ocean-atmosphere interaction is included?
•The research leading to these results has
received funding from the European Union
7th Framework Programme (FP7 2007-2013),
under grant agreement n.308299
•NACLIM www.naclim.eu