Etude du cycle hydrologique des régions boréales et apports de l'altimétrie à large fauchée

• Main Author: Biancamaria, Sylvain
• Other Authors: GOHS, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier - Toulouse III, Nelly Mognard
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2009
• Subjects: Arctic; hydrological cycle; snow; modelling; data assimilation; river; discharge; lake; volume variation; wide swath altimetry; error budget; Arctique; cycle hydrologique; neige; modélisation; ISBA; LISFLOOD; assimilation de données; fleuve; débit; lac; variation de volume; altimétrie à large fauchée; SWOT; bilan d'erreur; [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; [SDE.MCG]Environmental Sciences/Global Changes; Arctique*; Climate change
• Online Access: https://theses.hal.science/tel-00455572; https://theses.hal.science/tel-00455572/document; https://theses.hal.science/tel-00455572/file/manuscrit_these_biancamaria.pdf

Arctic regions will be the most affected by climate change: therefore this work aims at studying the hydrological cycle of these regions. A new methodology to extract snow volume from radiometric data has been validated for the boreal regions and exhibits a different behaviour between snow volume over Eurasia and over North America. Yet, water volume variation is more difficult to estimate from currently available satellite data. That's why the potential of the new SWOT (Surface Water and Ocean Topography) mission, which will provide global water elevation maps, has been investigated. This has been done by implementing a virtual mission. The first step has been to model a Siberian river, the lower Ob, by coupling a land surface scheme and an inundation model. A realist estimation of the river discharge and water heights has been performed by tuning some of the models parameters. Then, SWOT synthetic observations have been assimilated in the modelling using a local Ensemble Kalman Smoother, leading to a significant decrease (more than 50%) of the modelling errors. The benefit of SWOT for all surface waters has also been studied. From in-situ rating curves and SWOT instrumental error, it has been shown that SWOT will provide an estimate of instantaneous river discharge with an error below 30%, if the river depth is above 1m. The error on the monthly discharge due only to the satellite temporal sampling decreases with drainage area, and should be lower than 20% for drainage area above 6,900 km2. Finally, it has been computed that annual volume variation for all the lakes in the world is around 9,000 km3. Currently, less than 15% of this lake storage change can be monitored with nadir altimeters, whereas SWOT will be able to observe from 50% to 65% of this volume variation Les régions boréales seront les plus affectées par le réchauffement climatique, c'est pourquoi cette thèse s'est intéressée à l'étude du cycle hydrologique de ces régions. Une nouvelle méthodologie d'extraction du volume de neige à partir de ...