Simulated Residence Times of Bottom Water in Kiel Bight

residence_times.zip is a zip-file containing the netcdf-file residence_times_zenodo_17227227.nc. The variable LDT is the simulated residence times or “times-since-last-disturbance” of bottom waters in Kiel Bight. The underlying model is MOMKI a regional ultra-high resolution model that captures the Kiel Bight from 9° 50.48' E to 10° 53.92' E and 54° 18.04' N to 54° 50.96' N. It is based on the Modular Ocean Model framework MOM4p1, as released by NOAA's Geophysical Fluid Dynamics Laboratory (Griffies, 2009). Model code and configuration are similar to those described in Dietze et al. (2014) and Dietze et al. (2021). Differences include spatial boundary conditions are now the Baltic Sea model MOMBA 1.2 (Dietze et al., 2014; Löptien et al., 2025), which covers the entire Baltic Sea with a horizontal resolution of 1 nautical mile (sea surface height, salinity and temperature). As atmospheric forcing we used 2-hourly ERA5 atmospheric reanalysis data (Hersbach et al., 2020; Hersbach, 2023). River runoff has been provided by the Baltic Sea Model Intercomparison Project (Gröger et al., 2022) and is based on the E-Hype model (Donnelly et al., 2016). Our residence times measure the times the water remained undisturbed within Kiel Bight - undisturbed with respect to the last contact with the atmosphere and contact with the model boundaries. Technically, this approach resembles the artificial tracers or “clocks” introduced in Dietze et al. (2009) and Dietze and Löptien (2021). Such clocks behave like dyes in that they are subject to transport processes just like temperature, salinity, and dissolved oxygen. In addition to being transported, the clocks continuously count up time in every grid box. The clock used here to estimate the residence times is reset to zero whenever a water parcel reaches the ocean surface or the model boundaries. References: Dietze, H., Löptien, U., and Getzlaff, K. (2014) MOMBA 1.1 – a high-resolution Baltic Sea configuration of GFDL’s Modular Ocean Model, Geoscientific Model Development 7, 1713-1731. https://doi.org/10.5194/gmd-7-1713-2014 Dietze, H. and Löptien, U. (2021). Retracing hypoxia in Eckernförde Bight (Baltic Sea). Biogeosciences 18(14), 4243-4264. DOI https://doi.org/10.5194/bg-18-4243-2021 Donnelly, C., Andersson, J. C. M., & Arheimer, B. (2016). Using flow signatures and catchment similarities to evaluate the E-HYPE multi-basin model across Europe. Hydrological Sciences Journal, 61(2), 255–273. https://doi.org/10.1080/02626667.2015.1027710 Griffies, S. M. (2010). Elements of MOM4p1. GFDL Ocean Group Technical Report No. 6, NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, USA, 444 pp. Available at: https://www.gfdl.noaa.gov/fms Gröger, M., Placke, M., Meier, H. E. M., Börgel, F., Brunnabend, S.-E., Dutheil, C., Gräwe, U., Hieronymus, M., Neumann, T., Radtke, H., Schimanke, S., Su, J., & Väli, G. (2022). The Baltic Sea Model Intercomparison Project (BMIP) – a platform for model development, evaluation, and uncertainty assessment. Geoscientific Model Development, 15, 8613–8638. https://doi.org/10.5194/gmd-15-8613-2022 Hersbach, H. (2023). ERA5 hourly data on single levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). https://doi.org/10.24381/CDS.ADBB2D47 Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., et al. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. https://doi.org/10.1002/qj.3803 Löptien, U., Renz, M., & Dietze, H. (2025). Major Baltic Inflows come in different flavours. Communications Earth & Environment, 6(1), 232. https://www.nature.com/articles/s43247-025-02209-0