EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

TRACMASS - A mass conserving trajectory code for ocean and atmosphere general circulation models

Aitor Aldama Campino1, Kristofer Döös1, Sara Berglund1, Dipanjan Dey1, Joakim Kjellsson2,3, and Bror Jonsson4
Aitor Aldama Campino et al.
  • 1Department of Meteorology, Stockholm University, Stockholm, Sweden (
  • 2GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
  • 3Christian-Albrechts-Universitat zu Kiel, Kiel, Germany
  • 4Plymouth Marine Laboratory, Plymouth, United Kingdom

We present the latest version of the TRACMASS trajectory code, version 7.0. The new version includes new features such as water tracing in the atmosphere, parameterisation scheme for sub-grid scale turbulence, generalisation of the tracer handling, etc. The code has also become more user friendly and easier to get started with. Previous versions of TRACMASS only allowed temperature, salinity and potential density to be calculated along the trajectories, but the new version allows any tracer to be followed e.g. biogeochemical tracers or chemical compounds in the atmosphere. The new parameterisation of sub-grid turbulence will enhance the kinetic energy and dispersion of trajectories in the ocean so that results from eddy-permitting ocean models (dx ∼25km) resemble those from “eddy-resolving” models (dx ∼8km). We will demonstrate some use cases of these new capabilities for atmosphere and ocean sciences. 

TRACMASS calculates Lagrangian trajectories offline for both the ocean and atmosphere by using already stored velocity fields, and optionally tracer fields. The velocity fields may be taken from ocean or atmosphere circulation models (e.g. NEMO, OpenIFS), reanalysis products (e.g. ERA-5) or observations (e.g. geostrophic currents from satellite altimetry). The fact that the numerical scheme in TRACMASS is mass conserving allows us to associate each trajectory with a mass transport and calculate the Lagrangian mass transport between different regions as well as construct Lagrangian stream functions. 

A live demonstration on how to set up, configure and run the TRACMASS code will be given.

How to cite: Aldama Campino, A., Döös, K., Berglund, S., Dey, D., Kjellsson, J., and Jonsson, B.: TRACMASS - A mass conserving trajectory code for ocean and atmosphere general circulation models, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6984,, 2020

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Presentation version 1 – uploaded on 02 May 2020
  • CC1: Comment on EGU2020-6984, Simone Zazzini, 04 May 2020

    Which parameterisation scheme for sub-grid scale turbulence is included in TRACMASS 7.0?