airGR issueshttps://gitlab.irstea.fr/HYCAR-Hydro/airgr/-/issues2020-02-27T10:39:43+01:00https://gitlab.irstea.fr/HYCAR-Hydro/airgr/-/issues/32Enable the GR models to ingest ensembles2020-02-27T10:39:43+01:00Thirel GuillaumeEnable the GR models to ingest ensemblesEnsembles are useful for data assimilation and probabilistic forecasting applications. It might be useful to add the possibility to give ensembles of meteorological forcing to the GR models. Presently ensembles are dealt with through loo...Ensembles are useful for data assimilation and probabilistic forecasting applications. It might be useful to add the possibility to give ensembles of meteorological forcing to the GR models. Presently ensembles are dealt with through loops on each member, but providing directly the ensembles could fasten the execution of the GR models (indeed, the present loops necessitate to relaunch the GR models at each time step).https://gitlab.irstea.fr/HYCAR-Hydro/airgr/-/issues/169Fix GR pathology2023-10-26T11:24:06+02:00Thirel GuillaumeFix GR pathologyIssue initially reported to Vazken and Charles by Wouter Knoben on the Excel GR4J in 2017, also reported recently by @laurent.strohmenger on GR5J recently.
Note: this issue concerns airGR but is not specific to the package, it comes fr...Issue initially reported to Vazken and Charles by Wouter Knoben on the Excel GR4J in 2017, also reported recently by @laurent.strohmenger on GR5J recently.
Note: this issue concerns airGR but is not specific to the package, it comes from the GR implementation.
Under some conditions (i.e. some parameters sets, some climatic conditions), the lower part of the GR models, namely the routing store and the exchange component, enter in a mode where it cannot escape anymore. Due to a positive X2 and a positive exchange larger than the routing store outflow, the routing store comes to an equilibrium and a non null discharge is produced, even though no more rainfall is injected.
This is very annoying, as the simulation quality becomes very poor. This issue may not be found under calibration, because a low objective function would lead to avoid these parameter sets, but some parameter sets can look ok under calibration and then give erroneous simulations, under a different climate for instance (e.g. high rainfall).
Included is the email exchange with Wouter Knoben colleagues.
[GR4J_pathology_Knoben.docx](/uploads/715ff50a3c0232a3125178db848fdc15/GR4J_pathology_Knoben.docx)
Attached also an R code reproducing the bug proposed by @laurent.strohmenger and augmented by the translation in R of the GR5J routing part producing the bug. It shows that X2 does not need to be larger than X3, oppositely to what was discussed in 2017.
[GR5J_bug.R](/uploads/4fc1d93321a41a052546d69d9b435427/GR5J_bug.R)
There is no solution to date, but this must be cured.v2.0https://gitlab.irstea.fr/HYCAR-Hydro/airgr/-/issues/150Implemente Daniela Peredo's work2022-07-19T08:50:53+02:00Thirel GuillaumeImplemente Daniela Peredo's workThat could be useful to add Daniela's work in airGR (see https://www.tandfonline.com/doi/full/10.1080/02626667.2022.2030864).
Maybe @paul.astagneau you have already implented it by the way?That could be useful to add Daniela's work in airGR (see https://www.tandfonline.com/doi/full/10.1080/02626667.2022.2030864).
Maybe @paul.astagneau you have already implented it by the way?