A modelling approach to diagnose the impacts of global changes on hydrology suspended sediment and organic carbon in an Asian tropical basin : the case of the Red River (China and Vietnam) Xi Wei To cite this version: Xi Wei. A modelling approach to diagnose the impacts of global changes on hydrology suspended sediment and organic carbon in an Asian tropical basin : the case of the Red River (China and Vietnam). Hydrology. Université Paul Sabatier - Toulouse III, 2019. English. NNT : 2019TOU30291. tel-03103956 HAL Id: tel-03103956 https://tel.archives-ouvertes.fr/tel-03103956 Submitted on 8 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THÈSE En vue de l’obtention du DOCTORAT DE L’UNIVERSITÉ DE TOULOUSE Délivré par l'Institut National Polytechnique de Toulouse Présentée et soutenue par Xi WEI Le 2 décembre 2019 Une approche de modélisation pour diagnostiquer les impacts des changements globaux sur l'hydrologie, les sédiments en suspension et le carbone organique dans un bassin tropical asiatique: cas du fleuve Rouge (Chine et Vietnam) Ecole doctorale : SDU2E - Sciences de l'Univers, de l'Environnement et de l'Espace Spécialité : Surfaces et interfaces continentales, Hydrologie Unité de recherche : ECOLAB - Laboratoire d'Ecologie Fonctionnelle et Environnement Thèse dirigée par Sabine SAUVAGE Jury M. Aldo SOTTOLICHIO, Rapporteur M. Xixi LU, Rapporteur M. José-Miguel SáNCHEZ-PéREZ, Examinateur M. Sylvain OUILLON, Examinateur M. Henrique Llacer ROIG, Examinateur M. Orange DIDIER, Examinateur Mme Sabine SAUVAGE, Directrice de thèse Mme Marine HERMANN, invitée 0 Acknowledgement Acknowledgement If you are going to ask me which part of the thesis is the most difficult part to write. My answer will be the acknowledgment part, as difficult as the discussion! The discussion, conclusion and perspective are to justify and to summary my scientific work, but the acknowledgment is to review and to put a full stop for my three-year both life and work. “Life is like a box of chocolate, you never know what you are gonna get.” I clearly knew that I would like to do a PhD abroad, but honestly, I did not expect that it was in France. The attractive and interesting part of life is its unpredictability: a person you met, an idea came out, a choice you made…Like a complex permutation and combination. Life provided me with a French “chocolates” in 2015, and then I made a choice to come to France, a country with history and culture, a country famous for liberty, equality and fraternity. Now when I look back, I am grateful for the “chocolate” I got and the choice I made. I really appreciate the China Scholarship Council (CSC) for founding and providing me with a chance for studying abroad. Surely, this opportunity is a significant treasure for both my life and scientific work. I also appreciate my supervisors Sabine Sauvage and José-Miguel Sánchez-Pérez for providing me with a PhD subject and accepting me as a member of the EcoLab. I appreciate the understanding and support of my family. I know they worry a lot for my health condition after my surgery and I know they prefer me staying close to them in order for me to better recover and to be taken care of. Since I was a kid, they always respect my choice and let me decide the way I want to take. Their selfless love and support are always with me wherever I go. In this context, in January 2017, I took pieces of luggage and flew 12 hours to France without any fear and with full of expectations for my new adventure, though I barely knew French and this country, beginning my life in Toulouse and my study in the EcoLab, and now I still remember the first breath I took when landed in France. During these three years, what I have learned is more than my PhD subject. The way and method of self-learning and doing research will absolutely benefit my future research works. In the beginning, works here were really tough for me. Reading one scientific article would cause me several weeks and after reading I forgot what I had read about, and I did not understand what the authors talked about. Sabine always encouraged and comforted me during the beginning, and she makes me realize that patience and enthusiasm are important for research works. For getting through the difficult beginning, my teammates: Roxelane Cakir, Clement Fabre and Jeremy Guilhen, helped me dealing many problems with the modelling. They are representatives of the good education system of engineering schools. Appreciation is also due to Juan Luis Lechuga Crespo, who is always willing to help me to figure out the problems, and to Chuxian Li, who is teaching me many learning methods. After one year and a half, I gradually got to know my research and work, and more and more professional questions came to me. Luckily, Sabine, José, Sylvain Ouillon, Thi Phuong Quynh Le, Didier Orange, Marine Herrmann, these researchers are there 1 Acknowledgement to guide me to go forward. They contributed to the conceptualization and methodology for my PhD work, helped me to improve my scientific articles, taught me to be rigorous in research. With their expertise, I am able to keep going and finish my thesis. And I am so glad to be supervised by them, especially my director Sabine who not only taught me something related to my scientific work but also life philosophy. Thanks for her toleration and understanding during these three years. Thanks José for proposing the directions and ideas for my study and the time he spending in guiding me. Thanks Sylvain for being there for my problems and questions. He was so friendly showing us around when we were in Hanoi. He proposed many nice ideas for my study and worked together with me to figure the questions out. Thanks Quynh for providing the organic carbon sampling data which allowed me to test the equations for calculating the organic carbon. Modelling work cannot be isolated from in-situ observations. The combining of in-situ and modelling methods help researchers better and easier carry out studies an solve problems. Great respects should give to the filed-work researchers with their continuous efforts on sampling work. Quynh is also a hard-working researcher who inspires and encourages me a lot. Thanks Didier and Marine for introducing us the LOTUS project and taking us as a member in this project. It is a nice project and I personally think this kind of cooperations can be also greatly applied to other developing countries. Thanks Didier for providing mang expertise ideas and suggestions of Vietnam which really helped me better understand my study area. The time in Hanoi with Didier was also cheerful. He is such a friendly and kind person whom you will always be happy around. Thanks Marine for helping me improving my scientific writing a lot. She taught me how to be more rigorous and convictive in scientific paper. She works efficiently, and carefully and always on schedule which I really admire. I would like to express my gratitude to Franck Gilbert, director of the EcoLab, Genevieve Soucail, director of the SDU2E doctoral school, Stephane Bonnet, associate director of the doctoral school. They are great group leaders. They are contributed to improve PhD study life and support PhD students when we come across problems. They organize activities and classes for PhD students, and they try their best to make international PhD students feel welcome and comforting. I really appreciate these efforts they made. Merci à Annick Correge, Marie-Jose Tavella, Yannick Combarieu, Paule Tabarelli et Caroline Duthier, qui se soucient de moi, qui ont un cœur en or et qui me font toujours sourire. Chaque fois que je leur demande de l'aide, ils font de leur mieux pour m'aider et sont patients avec mon mauvais français. Ce sont des personnes avec qui je souhaite rester en contact et continuer de partager des mots affectueux dans l’école. In my daily life, there are also many lovely people around. I am extremely grateful to my good friends here in Toulouse: Chuxian and Roxelane, inviting me out and introducing me new people. I am so grateful that Roxelane introduced me the Madagascar groups (Christopher Marifeno Honoré, Arivony Rakotonirina, Anaïs Estrade Totobesola and Ali Andria). They are so kind and easygoing, making my life 2 Acknowledgement here cheerful. Friends here in France like Abby Wanyu Liu, Vanessa Cristina Dos Santos, Manon Dalibard, Juan Luis Lechuga Crespo and Pankeyes Datok, also outside France: Huier Liu, Xue Mi, Bo, Victor Postel and Ramón Fuentes, they are so lovely. These people support me a lot during my stay in France. They listen to me, help me dealing with my troubles, comfort me, encourage me to be strong and to continue my study. They with my family are like a pillar of my life and spirit. The time with them was relaxing and cheerful. Accompanies from Marilen Haver, Lulu He, Yuewei Wang, Mei Zhang, Ya Huang, Margaux Jacober, Melody Darsou, Columba Martínez-Espinosa, Amina Mami, Juan Durango-Cordero, Amine Benabdelkader, Clement, Jeremy, Mélanie Raimonet, Thomas Rosset, Vivien Ponnou-Delaffon, Amine Zettam, Francesco Angelo Salvatore Ulloa Cedamanos, Xinda Wu, Liliana Dorticos, Minerva Llull, Rebeca Martinez and Roberta Bruschi will build my good memories in France too.