Submitted as: model description paper 23 Mar 2021

Submitted as: model description paper | 23 Mar 2021

Review status: this preprint is currently under review for the journal GMD.

HydroPy (v1.0): A new global hydrology model written in Python

Tobias Stacke and Stefan Hagemann Tobias Stacke and Stefan Hagemann
  • Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Strasse 1, 21502 Geesthacht, Germany

Abstract. Global hydrological models (GHMs) are a useful tool in the assessment of the land surface water balance. They are used to further the understanding of interactions between water balance components as well as their past evolution and potential future development under various scenarios. While GHMs are a part of the Hydrologist's toolbox since several decades, the models are continuously developed. In our study, we present the HydroPy model, a revised version of an established GHM, the Max-Planck Institute for Meteorology's Hydrology Model (MPI-HM). Being rewritten in Python, the new model requires much less effort in maintenance and due to its flexible infrastructure, new processes can be easily implemented. Besides providing a thorough documentation of the processes currently implemented in HydroPy, we demonstrate the skill of the model in simulating the land surface water balance. We find that evapotranspiration is reproduced realistically for the majority of the land surface but is underestimated in the tropics. The simulated river discharge correlates well with observations. Biases are evident for the annual accumulated discharge, however they can – at least to some part – be attributed to discrepancies between the meteorological model forcing data and the observations. Finally, we show that HydroPy performs very similar to MPI-HM and, thus, conclude the successful transition from MPI-HM to HydroPy.

Tobias Stacke and Stefan Hagemann

Status: open (until 18 May 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on gmd-2021-53', Anonymous Referee #1, 31 Mar 2021 reply
    • AC1: 'Reply on RC1', Tobias Stacke, 07 Apr 2021 reply

Tobias Stacke and Stefan Hagemann

Data sets

Land surface parameter fields at 0.5deg resolution for use with the HydroPy model Tobias Stacke and Stefan Hagemann

Model code and software

Source code for the global hydrological model HydroPy Tobias Stacke and Stefan Hagemann

Tobias Stacke and Stefan Hagemann


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Short summary
HydroPy is a new version of an established global hydrology model. It was rewritten from scratch and adapted to a modern object-oriented infrastructure to facilitate its future development and application. With this study, we provide a thorough documentation and evaluation of our new model. At the same time, we open our code base and publish the model’s source code in a public software repository. In this way, we aim to contribute to increase transparency and reproducibility in science.