Ocean Dynamics 
Ô Springer 
Number 
60°N 
58°N 
56°N 
54°N 
52°N 
50°N 
60°N 
58°N 
56°N 
54°N 
52°N 
50°N 
SST on 20140814+01 h 
Min 
Max 
60°N 
58°N 
56°N 
54° N 
52°N 
50°N 
3°W 0° 3°E 6°E 9°E 12°E 
3°W 0° 3°E 6°E 9°E 12°E 
3°W 0° 3°E 6°E 9°E 12°E 
3°W 0° 3°E 6°E 9°E 12°E 3°W 0° 3°E 6°E 9°E 12°E 3°W 0° 3°E 6°E 9°E 12°E 
Fig. 2 Example showing the number of forecasts per grid cell (a), ensemble minimum (b) and ensemble maximum (c), standard deviation (d), MME 
mean (e), and MME median (f) of SST 01-h forecast in the North Sea 
58°N 
58°N 
58°N 
56°N 
56°N 
56° N 
54°N 
54°N 
54° N 
52°N 
52°N 
52°N 
50°N 
50°N 
50°N 
60°N 
Stdev 
60°N 
Mean 
60°N 
Median 
FCOOGETM has similar large distances. However, the high 
uncertainty in the a velocity between 01 and 06 h of the fore 
cast is not obvious in the PVDs. Differences in SSC possibly 
occur due to the different boundary conditions of the models 
with varying tidal constituents and resolutions. The large dif 
ference between BSHHBM and BSHCMOD might also be 
due to different turbulence schemes in the models which pos 
sibly have an effect on the surface currents, in Fig. 5, some 
examples of PVDs with various structures on different days 
are shown. 
Depending on the variations in time series, the resulting 
PVDs exhibit smaller or larger differences also depending 
on the region (Fig. 5). In the upper Baltic Sea, i.e., Bothnian 
Sea (Tr53) or Gulf of Finland (Tr44), the tidal signal is quite 
low and SSC are mainly dominated by the wind or inertial 
currents. Trl3 displays a pattern in a tidally dominated region. 
Variations in PVD patterns occur due to differences in phase, 
current direction, and strength. As mentioned above, 
differences in boundary conditions and especially tidal con 
stituents of the models might cause the differences in current 
patterns. Although mostly current forecasts in the upper 5-m 
mean are used for the MME, the different layer thicknesses of 
the original models might still have an impact on the strength 
and direction of the currents. 
The hourly figures showing the MME of SSC, accompa 
nied by some statistics, are only created for the first 24 h of 
the whole forecast period. The example shown in Fig. 6 dis 
plays a forecast close to a storm event over the North Sea. 
Mean and standard deviation are highest close to the eastern 
coast of Great Britain and in the English Channel. This pat 
tern is also reflected in the difference-to-standard-deviation 
ratio. The stability of the MME is very low in the regions 
where the current strength is also low (blue areas in MME 
mean), and high angular differences between the MME mean 
and the MyOcean product occur. For this storm event, the 
values in high angular difference are related to weak currents