Climatology of snow cover and snow water equivalent

• Chapter VI: Snow cover days in the Baltic States derived from satellite measurements
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• General remarks
• Validation with ground-based data
• Inter-annual variation in snow cover days
• Seasonal cycle of snow cover

Inter-annual variation in snow cover days

There is large inter-annual variation in snow cover days in the Baltic region. The number of days with snow cover can vary by a factor of 4 from year to year (Fig. 3). Higher variation is observed in coastal regions since there are more winter thaws in a maritime climate and the snow cover is often ephemeral and patchy.

Figure 3 shows that the lowest number of SCDs in all three locations occurred in the winters of 2006-07 and 2007-08. The winters were exceptionally warm and in many parts of the region permanent snow cover did not form at all. Another exceptional winter was 2012-13 when the cold weather continued till the middle of April and in many locations the annual number of SCD was highest during the analysed 13-year period (Fig 4).

Figure 3: Comparisons of snow cover days at different meteorological stations. MS - in-situ measurements at meteorological stations, MODIS - snow cover days derived from satellite measurements.

Figure 4: Annual number of snow cover days. On the left: winter 2007-08; on the right: winter 2012-13. Annual SCD during these two winters differed by a factor of 4.