Missions

Droughts are a growing concern for water managers, with the prospect of more severe and more frequent events due to climate change. One way to mitigate the consequences of water shortages is to use forecasting systems to better anticipate these events. In France, the PREMHYCE project (2012-2019) has developed a multi-model approach for forecasting low water levels and has proven its ability to become an operational online system on a small number of sites. As a follow-up to PREMHYCE, the CIPRHES project aims to take a step forward compared to existing approaches, by building an integrated chain for forecasting low water levels and discharge based on an original multi-model approach, by developing “seamless” weather forecasts (from one day to several months), integrated hydrological modeling and methods for quantifying uncertainties. The forecasting chain will be the subject of "crash tests" on a large sample of watersheds in order to assess its performance and robustness. Its usefulness for improving water management in some strategic socio-economic sectors will also be assessed.

Activités

The successful candidate will contribute to the development of a data assimilation framework within the ISBA-CTRIP hydrological model developed at CNRM. The objective is to improve the seasonal low flow forecast by correcting the model initial state with the integration of real-time observations, as done in numerical weather prediction systems.

The work program includes several phases:
• Set up the assimilation framework over several French basins
The first task will consist in implementing the existing Hydrological Data Assimilation System (HyDAS) over several French basins. The selection of basins will include basins with various sizes, hydroclimatological conditions, and anthropogenic pressure.
• Evaluation of the forecast performances of HyDAS
HyDAS will be tested in real conditions over the selected basins. In a reference simulation, meteorological forecasts over a recent period, that are developed in the CIPRHES project, will be used to force the model in forecast mode. Then real discharge observations will be assimilated into the CTRIP river routing model to improve the initial state, and a new forecast simulation will be done and compared to the reference simulation. Several criteria will be used to evaluate the performances of HyDAS, including standard hydrological criteria as well as forecast scores.
• Integration of anthropogenic factors into the model
In this step, recent developments concerning anthropogenic factors will be activated in the ISBA-CTRIP model and the new forecast performances will be assessed. These developments mainly include dam-reservoir management, and possibly water withdrawals for irrigation.
• Real-time implementation
Once the methodology has been developed and validated, a real-time system will be set up to make the HyDAS available to the PREMHYCE modeling plateform.

The candidate will work within the SURFACE team team of CNRM. He will have regular contacts and exchanges with the project partners, in particular through the working meetings of the CIPRHES project.

Compétences

PhD in the field of hydrology or water sciences
Computing skills: Python language, NetCDF data processing, Linux system
Written and oral communication skills, experience in publishing scientific articles
Experience in statistics, forecasting or data assimilation will be appreciated.

Contexte de travail

The postdoctorate is being offered as part of the CIPRHES project, "Chaine Intégrée pour la Prévision Hydrométéorologique des Étiages et des Sécheresses" (Integrated Chain for the Hydrometeorological Prediction of Floods and Droughts). The position is located at the Centre National de Recherches Météorologiques in Toulouse, a joint research unit of Météo-France and the CNRS. The candidate will work in the Medium-Scale Meteorology Group, in the SURFACE team, which is particularly involved in hydrology.

Contraintes et risques

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Informations complémentaires

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