The Trajectory Reader Plugin

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We would like to announce the development of a visualization component in collaboration with the GEOMAR “Theory and Modeling” group. The Trajectory Reader is a customized ParaView plugin that enables the reading and rendering of trajectories stored in the NetCDF file format.

The Trajectory Reader implements the Discrete Sampling Geometries section of the CF-conventions. The geospatial and temporal location of the data is defined accordingly with the help of coordinates attributes: the latitude, longitude and time coordinates are mandatory, while a vertical coordinate may be specified optionally.

We plan to extend the software with trajectory profiles reading functionalities (i.e. trajectories which have vertically varying profile data at each horizontal location, for example ship soundings). Our long-term objectives are to consolidate the software into a first release version and provide it eventually as an open-source visualization tool for the climate sciences community. In case you would like to learn more about the Trajectory Reader, please e-mail us at felicia.brisc@uni-hamburg.de.

Shown in the video: Oceanic currents around southern Africa form a unique configuration. The Agulhas Current flows within 30 - 50 km of the east coast of South Africa. It transports warm and salty waters from the Indian Ocean poleward. At the southern tip of the continent, a large portion of the current veers, joining the eastward flowing Agulhas Return Current. About 25 % of the warm and salty waters of the Agulhas Current flow into the South Atlantic. Due to the energetic interactions and abrupt change in direction, the exchange between the Indian Ocean and South Atlantic Ocean occurs in the form of eddies and filaments. It is believed that this injection of heat and salt into the Altantic has the potential to modulate its overall circulation on multi-decadal to millennial timescales. 

The video shows what happens to virtual particles released in bulk within the Agulhas Current. The combination of trajectories and current velocities gives an impression of the flow pattern of the Agulhas Current System. For the most part particles swiftly flow downstream reaching the retroflection. For there, they part ways either by entering the South Atlantic Ocean in a convoluted fashion, or by meandering back eastward into the Indian Ocean. A small portion of the particles re-circulates offshore the Agulhas Current.