Ocean Dynamics 
Ö Springer 
Transect number 
Fig. 23 Mean correlation between the forecasts (blue) and between the MME and the forecasts (red) at transects in regions I- VII for time series covering 
the period 01.04.2013-31.05.2015. The number of data points and products involved in the statistics are also indicated 
the MME median are FCOOGETM and BSHHBM at most 
transects in regions IV-VI and RBINSOPTOSNOS in re 
gions I and II. The high RMSD of FCOO GETM in region 
VII, already detected in Fig. 23, is caused by opposed transport 
patterns in the data. 
5 Summary 
A description of a new MME for SST, SSS, SSC, and TRA has 
been provided, and the contributing individual ocean forecasting 
models have been presented. The models are characterized by 
differences in numerical schemes, parametrizations, boundary 
conditions, forcing fields, and spatial resolutions. The processes 
of the MME system have been described, and some examples of 
the daily products including ensemble statistics such as standard 
deviation, ensemble mean, and ensemble median have been 
shown. In this study, the uncertainty between the forecasts is 
mainly expressed by the standard deviation and individual 
methods of comparisons, such as CV index or RMSD. 
In the daily products, high standard deviation for SSS was 
detected mainly in the Skagerrak and Kattegat, thus the Tran 
sition Area between North Sea and Baltic Sea. SSC are eval 
uated by standard deviation, stability, and angular difference 
between the MME mean and the nominal MyOcean product. 
Regions with low current strength in the MME mean are ac 
companied by high relative uncertainty between the forecasts. 
However, as expected, the standard deviation is high in re 
gions with stronger currents, since it scales with the absolute 
current values. Areas of high and low standard deviation vary 
also with the tides. The PVDs, calculated from the SSC time 
series, revealed a variety of patterns typical for different re 
gions of the study area ranging from tidally dominated in the 
North Sea to density- and wind-driven currents in the Transi 
tion Area and the Baltic Sea. Large disagreements in the time 
series and corresponding PVDs of the forecasts are caused by 
variations in current amplitude and phase. These differences 
are possibly related to the different boundary conditions and 
turbulence schemes of the models. The deviation of transport 
data is expressed by the variation coefficient which was found 
Fig. 24 The normalized RMSDs 
between the time series of each 
product and the MME median 
covering the period 01.04.2013- 
31.05.2015 are displayed for each 
region I-VII 
n I I r 
I 
n I I I I I r 
II 
n I I I I i r 
III 
n I I I r 
IV 
n I I r 
V 
H I I I I I i r 
VI 
n r 
VII 
• BSH_CMOD 
• DMLHBM 
- 
• METUK_FOAM 
- 
• RBINS_OPTOS_NOS 
- 
• 
• BSHJHBM 
- 
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- 
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1 47101514 13 12 11 19 20 23 22 21 9 6 5 2 28 27 26 25 24 46 45 44 43 52 50 49 41 36 32 30 29 38 42 
Transect Number