MOM-ERGOM western Baltic Sea simulations with tagging of atmospheric nitrogen deposition by EMEP

Project: HBM-ERGOM western Baltic Sea simulations with tagging of atmospheric nitrogen deposition within the MeRamo project - The MeRamo project (Unterstützung der mit der Umsetzung der EU Meeresstrategie-Rahmenrichtlinie befassten Behörden mittels eines assimilativen Ökosystems) was funded within the German national budget for the EU Copernicus Programme (BMVI Grand 50EW1601). The aim of the project was to link EU Copernicus services -- namely Sentinel remote sensing data -- with a marine biogeochemical model system (HBM-ERGOM). Additionally, the contribution of nitrogen from atmospheric deposition to the marine nitrogen budget was to assess. Two scientific questions were derived for the second project focus: - What contribution does atmospheric nitrogen deposition in total and atmospheric deposition of nitrogen from shipping and agricultural activities have to the nitrogen budget in the marine surface layer of the western Baltic Sea? - What is the impact of the spatial resolution of nitrogen deposition data on the biogeochemical model predictions in highly structured coastal areas in the western Baltic Sea region? To deal with these questions, the model system HBM-ERGOM was extended by a nutrient tagging/tracing approach and model simulations with tagged atmospheric nitrogen compounds were performed at the North-German Supercomputing Alliance (HLRN, project id: mvk00054, zulassung.hlrn.de/kurzbeschreibungen/mvk00054.pdf). Three different nitrogen deposition data sets were used for the model simulations. Two spatial highly resolved deposition data sets were provided by the EU BONUS Project SHEBA (Karl et al., 2019, doi:10.5194/acp-2018-1317) and one deposition data set was provided by the Norwegian Meteorological Institut (MetNo, 2016) for the European Evaluation and Modelling Programme (EMEP). The year 2012 was simulated. The North Sea and Baltic Sea were covered by the model domain but only results for the western Baltic Sea are provided here. The latter data were presented in Neumann et al. (2018, doi:10.5194/os-2018-71). Summary: A marine physical biogeochemical model simulation was performed with the model MOM-ERGOM for the years 2003 to 2014 covering the Baltic Sea. Previously, MOM-ERGOM had been initialized for several decades without tagging until 1999 and, then, from 2000 to 2002 with tagging (see below). The model output has been validated with measurement data of the "IOW Baltic Monitoring and long-term data program" (https://www.io-warnemuende.de/iowdb.html; IOW: Leibniz Institute for Baltic Sea Research Warnemünde) and from the HELCOM database (http://ocean.ices.dk/helcom/Helcom.aspx; HELCOM: Helsinki Commission). A publication is in preparation.