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Working Group: Atmosphere, Ice and Ocean


Jennifer Brauch

Wikis   AIO and NEMO-Europe

Overall Objective

The main general aim is to improve the representation of the regional ocean and its interaction with the atmosphere in the COSMO-CLM.

State of the art, scientific developments

Regional climate models (RCMs) are tools for dynamical downscaling coarse results from global climate circulation models (CGCMs), which are nowadays mainly coupled atmosphere-ocean models (AOGCMs). Ideally RCMs should be able to determine the regional climate without influence of the CGCMs, except at the lateral boundaries. However, presently this is not the case for COSMO-CLM, since the lower boundary values over sea are taken from the AOGCMs. This has a major impact on the quality of the regional model simulations as shown already for the Baltic Sea. To overcome this problem regional coupled atmosphere-ocean models may be used for climate simulations. Several groups in the CLM-Community are working on the coupling of a regional ocean to COSMO-CLM.

Objectives of participating groups

  • Improve the representation of the ocean and the interaction with the atmosphere in the COSMO-CLM (Goethe University Frankfurt, BiK-F)
  • Better regional representation of North Sea and Baltic Sea in climate simulations (Hereon)
  • Simulating polynya processes in the Laptev Sea and the Weddell Sea with a fully coupled A-I-O model (University Trier)
  • Assess the added value of high resolution climatic hindcasts and scenarios for the Mediterranean when using coupled atmosphere-ocean models (IMK-TRO (KIT))
  • To get a better accuracy, since in the CIRA simulations the lower boundary values over sea are taken from the global coupled model CMCC-MED. A better regional representation of the Mediterranean Sea is also important in order to increase the accuracy also for climate simulations of the Alpine space (CIRA)
  • Carry out simulations over the Southern Ocean to investigate seasonal simulations covering the confluence region of the Brazil and Malvinas currents, where many oceanic eddies occur (C2SM-ETHZ). Thereby two major questions are addressed:
    - What is the impact of the highly resolved SST on fluxes between the atmosphere and the ocean and on the lower troposphere? Are highly resolved SSTs required to realistically represent fluxes of heat and freshwater in that region?
    - How are these processes affected by the coupling between the atmosphere and the ocean?



The red boxes give a rough idea of the domains, however, they do not represent the exact boundaries.

Models: Ocean / Ice / RunoffRegionScientistsInstitutionStatus
NEMO / (LIM) / TRIPMediterranean Sea, North Sea, Baltic SeaJennifer Brauch, Bodo Ahrens, Trang van Pham, Naveed AkhtarGUF, BiK-F, DWDrunning
NEMO / (LIM) / HDNorth Sea, Baltic SeaHa Hagemann, Burkhardt RockelHereonrunning
TRIM / CICE /North Sea, Baltic SeaHa Hagemann, Burkhardt RockelHereondevelopment stopped
FESOM / FESOM | CCLM /Arctic, Laptev Sea, SvalbardOliver GutjahrMPI-Mplanned
NEMO?/ (LIM) /(Western) Mediterranean, Northeast AtlanticHendrik Feldmann, Gerd Schädler, Hans-Jürgen PanitzIMK-TRO (KIT)no update available
NEMO / (LIM) /Mediterranean SeaAndreas WillBTU Cottbusplanned
NEMO / (LIM) /Mediterranean Sea

Leone Cavicchia, Antonella Sanna, Silvio Gualdi and Paolo Oddo

CMCCno update available
ROMS / /Southern AtlanticDavid Byrne, Lukas PapritzETHZno update available
MOM / SIS /ERGOMBaltic SeaMarkus Meier, Claudia FrauenIOWplanned
Ocean model /CORDEX East AsiaDonghyun LeePohang University of Science and Technology, South Koreaplanned


DateMeeting and LocationDocuments
2017/09/19CLM-Assembly in Graz
2017/03/09ICCARUS in Offenbach
2016/09/19CLM-Assembly in Lüneburg
2013/08/29CLM-Community Assembly in Zürich

Icon PDF Minutes [52 kb]

2013/03/07COSMO/CLM Seminar in Offenbach

Icon PDF Minutes [42 kb]

2012/09/17CLM-Community Assembly in Leuven
2012/03/08COSMO/CLM Seminar in Offenbach
2011/08/30CLM-Community Assembly in Cava de' Tirreni

Icon PDF Minutes [27 Kb]

Icon PDF ETHZ Davin [211 Kb]

Icon PDF BiK-F/FUB Brauch/Dobler [976 Kb]

Icon PDF HZG Ho [1.3 Mb]

Icon PDF Presentation of WG AIO [161 Kb]

2011/03/03COSMO/CLM Seminar in Langen
2010/08/31Startup Meeting in Berlin


2011/08/26 Icon PDF  Annual report 2011 [79 Kb]

2012/09/13   Annual report 2012 [88 kb]

2013/09/17   Annual report 2013 [110kb] 


Akhtar, N., J. Brauch, B. Ahrens (2017): Climate Modeling over the Mediterranean Sea: Impact of Resolution and Ocean Coupling. Clim. Dyn. DOI 10.1007/s00382-017-3570-8

Akhtar, N.J., J. Brauch, A. Dobler, K. Béranger, B. Ahrens (2014): Medicanes in an ocean-athmosphere coupled regional climate model. Nat. Hazards Earth Syst. Sci., 14, 2189-2201, doi:10.5194/nhess-14-2189-2014

Byrne, D., M. Münnich, I. Frenger, N. Gruber (2016): Mesoscale atmosphere ocean coupling enhances the transfer of wind energy into the ocean, Nature Communications 7, doi:10.1038/ncomms11867

Ho-Hagemann, H.T.M., Hagemann, S., Grayek, S., Petrik, R., Rockel, B., Staneva, J., Feser, F., & Schrum, C. (2020): Internal Model Variability of the Regional Coupled System Model GCOAST-AHOI. Atmosphere 2020, 11, 227, doi:10.3390/atmos11030227

Ho-Hagemann, H.T.M., & Rockel, B. (2018): Einfluss von Atmosphäre-Ozean Wechselwirkungen auf Starkniederschläge über Europa. In: Lozán, J.L., Breckle, S.-W., Graßl, H., Kasang, D., & Weisse, R. (Hsg.): Warnsignal Klima: Extremereignisse,

Ho-Hagemann, H., Gröger, M., Rockel, B., Zahn, M., Geyer, B., Meier, M., 2017: Effects of air-sea coupling over the North Sea and the Baltic Sea on simulated summer precipitation over Central Europe, Climate Dynamics,pp 1–26, doi:10.1007/s00382-017-3546-8.

Ho-Hagemann, H.T.M., S. Hagemann, B. Rockel (2015): On the role of soil moisture in the generation of heavy rainfall during the Oder flood event in July 1997. Tellus A, 67, 28661. DOI:10.3402/tellusa.v67.28661.

Ho-Hagemann H, Rockel B, Kapitza H and Geyer B (2013): COSTRICE-an atmosphere-ocean-sea ice model coupled system using OASIS3, HZG Report (2013-5), 24pp

Pham, Trang Van; J. Brauch, B. Früh, B. Ahrens (2017): Simulation of snowbands in the Baltic Sea area with the coupled atmosphere-ocean-ice model COSMO-CLM/NEMO. Met. Z., doi: 10.1127/metz/2016/0775

Pham, T.V., J. Brauch, C. Dieterich, B. Früh, B. Ahrens (2014): New coupled atmosphere-ocean-ice system COSMO-CLM/NEMO: On the air temperature sensitivity on the North and Baltic Seas. Oceanologia, 56(2), 167-189, doi:10.5697/oc.56-2.167

Rockel, B., J. Brauch, O. Gutjahr, N. Akhtar, H.T.M. Ho-Hagemann (2017): Gekoppelte Modellsysteme: Atmosphäre und Ozean. Promet - Meteorologische Fortbildung, 99, 65-75

Ruti P.M., S. Somot, F. Giorgi, C. Dubois, E. Flaounas, A. Obermann, A. Dell'Aquila, G. Pisacane, A. Harzallah, E. Lombardi, B. Ahrens, N. Akhtar, A. Alias, T. Arsouze, R. Aznar, S. Bastin, J. Bartholy, K. Béranger, J. Beuvier, S. Bouffies-Cloché, J. Brauch, W. Cabos, S. Calmanti, J.-C. Calvet, A. Carillo D. Conte, E. Coppola, V. Djurdjevic, P. Drobinski, A. Elizalde-Arellano, M. Gaertner, P. Galàn, C. Gallardo, S. Gualdi, M. Goncalves, O. Jorba, G. Jordà, B. L'Heveder, C. Lebeaupin-Brossier, L. Li, G. Liguori, P. Lionello, D. Maciàs-Moy, P. Nabat, B. Onol, B. Rajkovic, K. Ramage, F. Sevault, G. Sannino, M.V. Struglia, A. Sanna, C. Torma, V. Vervatis (2016): MED-CORDEX initiative for Mediterranean Climate studies. Bull. of the American Meteorological Society, 97(7), 1187-1208, doi: 10.1175/BAMS-D-14-00176.1

Will,A., N. Akhtar, J. Brauch, M. Breil, E. Davin, H. T. M. Ho-Hagemann, E. Maisonnave, M. Thürkow, and S. Weiher (2017): The COSMO-CLM 4.8 regional climate model coupled to regional ocean, land surface and global earth system models using OASIS3-MCT: description and performance. Geoscientific Model Development, 10:1549–1586, doi:10.5194/gmd-10-1549-2017


Bodo Ahrens, Naveed Akhtar, Jennifer Brauch, Sandra Brunnabend, David Byrne, Manuel Dröse, Hendrik Feldmann, Claudia Frauen, Barbara Früh, Oliver Gutjahr, Ha Hagemann, Günther Heinemann, Astrid Kerkweg,  Svenja Kohnemann, Praveen Kumar, Donghyun Lee, Hans-Jürgen Panitz, Lukas Papritz, Cristina Primo, Burkhardt Rockel, Gerd Schädler, Christoph Stegert, Trang Van Pham, Andreas Will, Rolf Zentek

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Coordinator Alumni List

Bodo Ahrens (2014 - 2016)

Burkhardt Rockel (2010 - 2014)

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