Simulated 2D residual velocity fields in the inner German Bight were subjected to Principal Component Analysis (PCA). Residual currents were obtained from coastDat2 barotropic 2D simulations with the hydrodynamic model TRIM-NP V2.1.22 in barotropic 2D mode on a Cartesian grid (1.6km spatial resolution) stored on an hourly basis for the years 1948 - 2012 (doi:10.1594/WDCC/coastDat-2_TRIM-NP-2d) and later extended until August 2015. The present analysis refers to the period Jan 1958 - Aug 2015. The spatial domain considered is the region to the east of 6 degrees east and to the south of 55.6 degrees north. All grid nodes with a bathymetry of less than 10m were excluded. Residual velocities were calculated in two different ways: 1.) as 25h means, 2.) as monthly means. Both types of residual current data are available from * RESIDUAL_CURRENTS_195801_201508 The directory contains sub-directories for years and months. Daily residual currents for the 13th of September 1974, for instance, are stored in * RESIDUAL_CURRENTS_195801_201508/YEAR_1974/MONTH_09/TRIM2D_1974_09_13_means.nc while monthly mean residual currents for September 1974 are stored in: * RESIDUAL_CURRENTS_195801_201508/YEAR_1974/TRIM2D_1974_09_means.nc All current fields provided were interpolated from the original Cartesian model grid to a more convenient regular geographical grid (116x76 nodes). Mean residual currents are stored in: * mean_residual_currents.nc This data set contains residual velocities both on original Cartesian grid nodes and interpolated to the geographical grid. An example plot is provided: * mean_residual_currents.png For PCA, two residual velocity components from each of 12133 Cartesian grid nodes were combined into one data vector (length 2x12133), referring to 21061 daily or 692 monthly time levels. Results of two independent PCAs for either daily or monthly mean fields are stored in: * PCA_daily_residual_currents.nc * PCA_monthly_residual_currents.nc Files contain three leading Principal Components (PCs) and corresponding Emipirical Orthogonal Functions (EOFs). Again EOFs were also interpolated to a regular geographical grid. PC time series are also stored in plain ASCII format: * PCs_daily.txt * PCs_monthly.txt For monthly fields the number N of variables (N=2x12133) is much larger than the number T of time levels (T=692). Therefore, to reduce computational demands, the roles of time and space were formally interchanged. Having conducted the PCA the EOFs were then transformed back to the original spatial coordinates (cf. Section 12.2.6 in von Storch and Zwiers (1999), Statistical Analysis in Climate Research, Cambridge University Press). A much larger number of time levels made even this approach prohibitive for the full set of daily data. Therefore, PCAs were performed for six sub-periods (1958-1965, 1966-1975, 1976-1985, 1986-1995, 1996-2005, 2006-2015(Aug)) independently. EOFs obtained from these six sub-periods were then averaged to obtain EOFs representative for the whole period. Corresponding PCs were calculated by projecting daily fields onto these average EOFs. IMPORTANT: In contrast with PCA of monthly data, the PCA of daily data INVOLVES SOME APPROXIMATIONS! EOFs on the original nodes were normalized to have unit lengths. The following figures, * daily_EOF1.png * daily_EOF2.png * daily_EOF3.png show the first three EOFs obtained from daily data, assuming that corresponding PCs have the value of one standard deviation. The following two plots, * monthly_EOF1.png * monthly_EOF2.png show the leading EOFs for monthly mean data. EOF3 is omitted as it represents just a very small percentage of overall variance (1.7%).

The experiment contains baroclinic hindcast simulations of the North Sea by the hydrodynamic model HAMSOM (Pohlmann, 2006) for the period 1948-2007. HAMSOM was set up at a spatial resolution of 20' x 12' and with 19 vertical levels (5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 75, 100, 150, 200, 250, 350, 600 and 1000m, lower boundary level). The data-set contains hourly output of temperature, salinity, u- and v-component (3-dim) and water level (2-dim). At the open boundaries, lateral boundary conditions are obtained from a coarser, large-scale Northwest-European shelf sea model driven by climatological temperature and salinity obtained from Levitus (1982). For water levels, in addition the eight significant tidal constituents (M2, S2, N2, K2, K1, O1, Q1 and P1) are included and weather effects are accounted for by using wind and pressure fields from the NCEP/NCAR Reanalysis 1 (Kalnay et al., 1996). Due to technical reasons at the lateral boundaries the water level was added by 0.5m. Atmospheric forcing was obtained from NCEP/NCAR Reanalysis 1 data-set comprising near-surface air-temperature, humidity, cloud cover, precipitation, sea level pressure and near surface wind speed and direction. The output format is netCDF.

This is an atmospheric hourly hindcast for Western Europe and the North Atlantic using REMO with spectral nudging from 1948-2007. The model uses a rotated grid with 81 x 91 grid points and a grid point distance of 0.5 degrees, the North pole is located at 170 W, 32.5 N. In rotated coordinates the model area extends from 19.5 W to 20.5 E, 25 S to 20 N, in geographical coordinates this corresponds to about 10.4 W to 70.7 E, 29.6 N to 67.8 N.

COSMO-CLM simulation for Bohai, Yellow and East China Sea: System Analysis and Modelling Group at the Helmholtz-Zentrum Geesthacht Centre for Materials and Coastal Research (referred to hereinafter as data producer) has computed the regional climate simulation. By making these data available, the data producer wishes to stimulate and support climate change and impact research projects. The data producer is aiming to make the results produced on the basis of these data available on its website and in publications as part of an international overview of regional climate change research. All interested users will have access to the simulation data being calculated with high resolution both in space and time. The data were computed at the German Climate Computing Centre (DKRZ) in Hamburg using the regional climate model COSMO-CLM. The simulations were carried out with support by the China Scholarship Council, the Helmholtz Climate Initiative REKLIM and the CLM community.

Regional simulation with the fully coupled physical-biogeochemical model ECOSMO II. Model details and setup specifications are described in Daewel and Schrum (2013). The basis for ECOSMO II is a baroclinic hydrodynamic coupled sea-ice model (Schrum and Backhaus, 1999), which is coupled to a lower trophic level ecosystem NPZD-model. The experiment contains hindcast simulations for the coupled North Sea and Baltic Sea ecosystem for the period 1948-2008 forced by the NCEP/NCAR reanalysis (Kalnay et al., 1996). The spatial resolution is 6’ x 10’ in the horizontal and 20 layers in the vertical. The data-set contains daily averaged data. Data for biological, physical and ice variables are stored in separate files. The 3d model grid is defined in ECOSMOII_NCEP.1948-2008.dm.griddef.000000.nc (https://cera-www.dkrz.de/WDCC/ui/cerasearch/entry?acronym=ECOSMOII_NCEP_griddef ), which contains information on vertical layer thickness in each model grid-box. The output format is netCDF.

Hindcast atmospheric simulation for the North Sea using COSMO6.0-CLMWF version driven with ERA-Interim reanalysis data and the wind farm parametrization from Fitch et al., 2012 (referenced by Elizalde, 2023) with wind turbines types (3.6, 5, 8, 10 and 15 MW rated capacity). The covered period is from 2008 to 2018 with hourly frequency output. The model uses a rotated grid with 356 x 396 grid points and a grid spacing of 0.02 degrees, the rotated North pole is located at 180 W, 30 N. We gratefully acknowledge financial support through the H2Mare PtX-Wind project with funds provided by the Federal Ministry of Education and Research (BMBF) under Grant No. 03HY302J.

Hindcast atmospheric simulation for the North Sea using COSMO6.0-CLM version driven with ERA5 reanalysis data. The covered period is from 2012 to 2022 with hourly frequency output. The model uses a rotated grid with 356 x 396 grid points and a grid spacing of 0.02 degrees, the rotated North pole is located at 180 W, 30 N. We gratefully acknowledge financial support through the H2Mare PtX-Wind project with funds provided by the Federal Ministry of Education and Research (BMBF) under Grant No. 03HY302J.

Potential generated power under the assumption of no wind farm interaction (wake effects neglected) using power formulation from the wind farm parametrization from Fitch et al., 2012 (referenced by Elizalde, 2023). Turbines rated capacity of 3.6 MW. Hindcast simulation for the North Sea using COSMO6.0-CLM version driven with ERA5 reanalysis data. The covered period is from 2012 to 2018 with hourly frequency output. The model uses a rotated grid with 356 x 396 grid points and a grid spacing of 0.02 degrees, the rotated North pole is located at 180 W, 30 N. We gratefully acknowledge financial support through the H2Mare PtX-Wind project with funds provided by the Federal Ministry of Education and Research (BMBF) under Grant No. 03HY302J.

Potential generated power under the assumption of no wind farm interaction (wake effects neglected) using power formulation from the wind farm parametrization from Fitch et al., 2012 (referenced by Elizalde, 2023). Turbines rated capacity of 15 MW. Hindcast simulation for the North Sea using COSMO6.0-CLM version driven with ERA5 reanalysis data. The covered period is from 2012 to 2018 with hourly frequency output. The model uses a rotated grid with 356 x 396 grid points and a grid spacing of 0.02 degrees, the rotated North pole is located at 180 W, 30 N. We gratefully acknowledge financial support through the H2Mare PtX-Wind project with funds provided by the Federal Ministry of Education and Research (BMBF) under Grant No. 03HY302J.

Hindcast atmospheric simulation for the North Sea using COSMO6.0-CLMWF version driven with ERA5 reanalysis data and the wind farm parametrization from Fitch et al., 2012 (referenced by Elizalde, 2023) with wind turbines of 3.6 MW rated capacity. The covered period is from 2012 to 2022 with hourly frequency output. The model uses a rotated grid with 356 x 396 grid points and a grid spacing of 0.02 degrees, the rotated North pole is located at 180 W, 30 N. We gratefully acknowledge financial support through the H2Mare PtX-Wind project with funds provided by the Federal Ministry of Education and Research (BMBF) under Grant No. 03HY302J.