10 
S. Schwegmann & J. Holfort: Baltic sea ice volume 1982-2019 
Meteorol. Z. (Contrib. Atm. Sci.) 
PrePub Article. 2020 
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Sum correlations of ASIV with 
NAO and SCAND 
K****9. K«mi 
Intel' 
Vyborg. 
BpB {¡^Petersburg 
Tallinn Narva 
Kiel W Gdansk' 
•Rostock Kotobrzeg 
Wivnar 
Mamburo SaaMk. 
^B 0.25 
0.3 
■1 0.2 - 0.25 
■ o.is 
0.2 
l~~l o.io 
0.15 
I 1006 
0.1 
10 0.05 
I I-0.05 
■ 0 
L_J -0.01 
-0.05 
BpwI -0.16 
■0.1 
-0 2- 
-0.15 
^B -0.25 
-0.2 
H -0.30 
• •0.25 
Figure 7: Correlation between total winter ASIV and the Northern Atlantic Oscillation Index (January to March sum, left) for the observation 
period 1982-2019. Positive NAO indices come together with increased westerly winds and a transport of warm air masses into the Baltic 
Sea, which would result in less sea ice volume. Hence, a negative correlation (blue) is expected. On the right hand side the sum of the 
correlations of ASIV with NAO and SCAND are depicted; with positive values, the correlation with SCAND is better than with NAO, and 
with negative values vice versa. 
m, but a 1 
0 
charts are still available in analog form, 
resolved digitization would be very tedious. Operational 
sea ice charts of the Baltic are also issued daily from the 
Swedish and Finnish ice services, but still not available 
in digital form for such a long time. Once available also 
the temporal resolution could be improved. 
better- Abbreviation list 
Acknowledgments 
NCEP Reanalysis data were provided by the NOAA/ 
OAR/ESRL PSD, Boulder, Colorado, USA, from their 
Web site at https://www.esrl.noaa.gov/psd/. The AO and 
SCAND indexes were provided by the Climate predic 
tion center at https://www.cpc.ncep.noaa.gov. Sea sur 
face temperature data were provided by the Copernicus 
Marine environment monitoring service (CMEMS). We 
would like to thank numerous ice observers who have 
collected ice information and forced a big improvement 
of the ice product. We would also like to thank for the 
reviewer's valuable comments. 
AO 
Arctic Oscillation 
ASIC 
accumulated sea ice concentration 
ASIV 
accumulated sea ice volume 
AVHRR 
Advanced Very High Resolution Radar 
BSH 
Bundesamt fiir Seeschifffahrt und 
Hydrographie 
CMEMS 
Copernicus Marine environment 
monitoring service 
ERS 
European Remote Sensing 
NAO 
North Atlantic Oscillation 
NCEP/NCAR National Center for Environmental 
Predictions/National Center for Atmo 
spheric Research 
NOAA 
National Oceanic and Atmospheric 
Administration 
SCAND 
Scandinavian Pattern 
SMHI 
Swedish Meteorological and Hydrologi 
cal Institute 
SST 
Sea Surface Temperature 
Thr 
2-m air temperature