Least travel time ray tracer version 2 (LTT v2) adapted to the grid geometry of the OpenIFS atmospheric model

Vasiuta, Maksym; Navarro Trastoy, Angel; Motlaghzadeh, Sanam; Tuppi, Lauri; Mayer-Gürr, Torsten; Järvinen, Heikki

doi:https://doi.org/10.5194/gmd-18-5015-2025

Articles | Volume 18, issue 16

https://doi.org/10.5194/gmd-18-5015-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/gmd-18-5015-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 16

Model description paper

|

18 Aug 2025

Model description paper |

| 18 Aug 2025

Least travel time ray tracer version 2 (LTT v2) adapted to the grid geometry of the OpenIFS atmospheric model

Maksym Vasiuta, Angel Navarro Trastoy, Sanam Motlaghzadeh, Lauri Tuppi, Torsten Mayer-Gürr, and Heikki Järvinen

Data sets

OpenIFS Data Hub ECMWF https://confluence.ecmwf.int/display/OIFS/OpenIFS+Data+Hub

Model code and software

Release of Least Travel Time model, version Two (LTT v2) M. Vasiuta https://doi.org/10.5281/zenodo.14237335

Least travel time (LTT) operator R. Eresmaa et al. https://doi.org/10.5281/zenodo.4834412

VieVS Ray-tracer (RADIATE) D. Landskron https://github.com/TUW-VieVS/RADIATE

GROOPS software toolkit: Release 2021-02-02 T. Mayer-Gürr https://github.com/groops-devs/groops/releases/tag/2021-02-02

Implementing sky-view represnetation of the Tropospheric Slant Delays in GROOPS A. Navarro Trastoy https://doi.org/10.5281/zenodo.14260394

pirkkao/OpenEPS: Initial release (v0.952) P. Ollinaho https://doi.org/10.5281/zenodo.3759127

IGS repro3 products by Graz University of Technology (TUG) (Version v1) S. Strasser and T. Mayer-Gürr https://doi.org/10.3217/dataset-4528-0723-0867

VieVS Ray-tracer (RADIATE) D. Landskron https://github.com/TUW-VieVS/RADIATE

GROOPS software toolkit: Release 2021-02-02 T. Mayer-Gürr https://github.com/groops-devs/groops/releases/tag/2021-02-02

The ecCodes software package S. Najm https://confluence.ecmwf.int/download/attachments/45757960/eccodes-2.22.1-Source.tar.gz?api=v2

Short summary

Propagation of electromagnetic signals in Earth's neutral atmosphere inflicts errors in space geodetic observations. To model these errors accurately, it is necessary to use a signal tracing algorithm which is informed of the state of the atmosphere. We developed such an algorithm and tested it by processing Global Navigation Satellite System network observations. Our algorithm's main advantage is lossless utilization of atmospheric information provided by numerical weather prediction models.