THÈSE

Gonza

Sujets

• Modelica
• Leaf Hound
• Flore méditerranéenne
• Prospective
• Soilwork
• Atmosphere (groupe)

Informations

• Publié par: Thoek
• Nombre de lectures: 223
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

THÈSE En vue de l'obtention du DOCTORAT DE L’UNIVERSITÉ DE TOULOUSE Délivré par l'Université Toulouse III - Paul Sabatier en cotutelle avec l'Universitat de València, Espagne Discipline ou spécialité : Télédétection Présentée et soutenue par María del Carmen González Sanpedro Le 01-12-2008 Titre : Optical and Radar Remote Sensing applied to agricultural areas in Europe. Télédétection radar et optique appliquée aux régions agricoles en Europe. JURY José Antonio Sobrino Rodriguez, Professeur de l’Universitat de València (Président de jury) Francesco Mattia, Chercheur CNR (Examinateur) Jean-Philippe Gastellu-Etchegorry, Professeur UPS Toulouse III (Directeur de thèse) Thuy Le Toan, Ingenieur de recherche CNRS au CESBIO (Directeur de thèse) José F. Moreno Méndez, Professeur de l’Universitat de València de thèse) Ecole doctorale : Sciences de l'univers de l'environnement et de l'espace Unité de recherche : CESBIO Directeur(s) de Thèse : Jean-Philippe Gastellu-Etchegorry, Thuy Le Toan et José F. Moreno Rapporteurs : Martine Guérif (Directeur de Recherche, INRA) et José Antonio Sobrino (Professeur de l’Universitat de València)   ACKNOWLEDGEMENTS I would like to thank my advisors, Dr. Tuy Le Toan and Dr. José Moreno for giving me the opportunity of working with them at CESBIO and at the University of Valencia respectively, as well as for helping me to accomplish this thesis. I am also very grateful with Dr. Martine Guèrif, Dr. Francesco Mattia, and Dr. José Sobrino who, as reviewers of my report, provided careful corrections. I am extremely grateful with my friends and colleagues at CESBIO. In particular I would like to mention Dr. Laurent Kergoat for his priceless scientific discussions and encouragement. Pendant cette étape dans le monde de la recherche j’ai eu la chance de rencontrer des personnes qui ont devenu très importantes pour moi. Je tiens donc à remercier toutes ces et à leur transmetre ici toute mon amitié. Sans aucun doute, vous avez été le meilleur de cette étape. Au CESBIO je remercie spécialement à Manuela Grippa famiglia(et à la Balochi au complet: Andrea, Mattia et Gaia). Également je remercie à Nicolas Delbart, Claire Gruhier, Silvia Juglea, Iskander Benhadj, Arnaud Mialon, Philippe Richaume, Olivier Merlin, Alex Bouvet, Frederic Frappart et Ahmad Albitar. Merci aussi à Julie Gardelle, qui a eu le courage de partager un bureau avec moi a la fin de ma thèse (bonne chance pour la suite!). Je remercie aussi d’autres amis qui ont passé par ce laboratoire il y a quelque temps: Erick Lopez, Daniel Kristoff (et Andrea “la otra ”), Joost Hodges, Sergio Vicente, Alberto García, Julianne l’Hermitte, Yannick Le Page, Mª José Escorihuela, Sylvie Duthoit, Laurent Coret, et Ferran Gascon. J’ai de très bons souvenirs du temps passé à Toulouse avec Lizbeth Guijarro qui sera toujours une bonne amie, même si elle est de l’autre côté de l’Atlantique. Un grand merci aussi aux permanents et “quasi- permanets” du CESBIO qui ont toujours été très aimables avec moi, spécialement je veux remercier à François Cabot (est-ce que tu sais ou il est Laurent?), Olivier Hagolle, Valérie Le Dantec, Valérie Demarez, Philippe Maisongrande (vive le Tour!), Pierre Hiernaux, Eric Mougin, et encore à Laurent et à Thuy. Je pense aussi tout particulièrement à Françoise Guichard, toujours très douce et très gentille avec moi. i  También quiero agradecer de corazón a quienes han sido mis compañeros de laboratorio en la Universidad de Valencia y con quienes compartí muchas risas: Luis Alonso (por los momentos frikis), José Carlos García, Carlos Cuñat, José Manuel Martínez, Luis Guanter, Juan Carlos Fortea y Gloria Fernández. También quiero agradecer muy especialmente a Siham Lanjeri todo su cariño y amistad. Por supuesto que no puedo olvidar tampoco a otros compañeros del departamento como Fernando Camacho. Tengo también un recuerdo para los buenos ratos pasados allá bajo el sol de la Mancha junto con Michael Whiting, Bob Zomer, y la lista es demasiado larga.., (gracias!). Y a mis compañeros de la facultad: Ana Campos, Antonio Pérez, Oscar Soler, Javier Cervera, José Juan Esteve, Julio Trujillo, María José Yusá, muy particularmente a Víctor Estellés, quien siempre supo ser un gran amigo incluso a distancia. Tengo un recuerdo muy bueno de mis amigas en Valencia: Laura, Pilar, Maribel, Meriam. Finalmente, quiero agradeceros a vosotras: Desirée, Carmen María, Rosaura, Ana, María Jesús, Rosa y Maite por vuestra paciencia y todas las veces que os dije “tengo que trabajar”. A mis padres. I moltes, moltíssimes gràcies a tu Pere, per ser al meu costat. Dankon belulo ! ii  ABSTRACT The global population growth, as well as the social and economic importance that the agricultural sector has in many regions of the world, makes it very important to develop methods to monitor the status of crops, to improve their management, as well as to be able to make early estimates of the agricultural production. One of the main causes of uncertainty in the production of crops is due to the weather, for example, in arid and semiarid regions of the world, periods of drought can generate big losses in agricultural production, which may result in famine. Thus, FAO, during their summit in June 2008, stressed the need to increase agricultural production as a measure to strengthen food security and reduce malnutrition in the world. Concern for increasing crop production, has generated, during the last decades, significant changes in agricultural techniques. For example, there has been a widespread use of pesticides, genetically modified crops, as well as an increase in intensive farming. In turn, the market influences crop rotations, and as a consequence, changes in the spatial distribution of crops are very common. Therefore, in order to make estimates of agricultural production, it is also necessary to map regularly the crop fields, as well as their state of development. The aim of this thesis is to develop methods based on remote sensing data, in the radar and optical spectral regions, in order to monitor crops, as well as a to map them. The results of this thesis can be combined with other techniques, especially with models of crop growth, to improve the prediction of crops. The optical remote sensing methods for classifying and for the cartography of crops are well established and can be considered almost operational. The disadvantage of the methods based on optical data is that they are not applicable to regions of the world where cloud coverage is frequent. In such cases, the use of radar data is more advisable. However, the classification methods using radar data are not as well established as the optical ones, therefore, there is a need for more scientific studies in this field. As a consequence, this thesis focuses on the classification of crops using radar data, particularly using AIRSAR airborne data and ASAR satellite data. The monitoring of crops by remote sensing is based on the estimation of biophysical parameters and their evolution over time. These parameters are, among others, LAI (leaf area index), chlorophyll and biomass. In this thesis, satellite data from LANSAT-TM are used for the inversion of LAI, and ENVISAT-MERIS data for estimating LAI and chlorophyll. Finally, ENVISAT-ASAR radar data are used to investigate its potential in the estimation of the biomass of cereals. Chapter 1 of the thesis introduces the context of this study and its scientific objectives. Chapter 2 presents the theoretical basis of optical remote sensing. iii  Chapter 3 is dedicated to the inversion of LAI in the region of Barrax (Castilla-La Mancha, Spain) using 12 LANDSAT-TM images acquired during the same agricultural season. The LAI is calculated using LUTs (Look Up Tables) to invert the radiative transfer model SAIL, which is coupled to the model of leaf reflectance PROSPECT. The results are validated with experimental measurements acquired during the field campaign ESA SPARC-2003, showing a good correlation. Chapter 4 proposes a method to invert, at the same time, LAI and chlorophyll data from ENVISAT-MERIS. This method involves an inversion of the same model, PROSPECT + SAIL, which was used in Chapter 3, but with the special addition of a temporal constraint. Thus, instead of inverting a single value of LAI and chlorophyll for each date, a curve for the entire crop cycle is inverted. This method seeks to take as much information as possible from the temporal dimension of the data. The results show that the multitemporal method works better than the inversions on a single date. However, the inversion of chlorophyll still requires further study. Chapter 5 introduces the concepts related to the radar remote sensing, which will be used along the second part of this thesis. In Chapter 6 a method of hierarchical classification of crops is developed. It uses polarimetric data in C band, from the airborne instrument AIRSAR. The method is applied to images in Flevoland (Netherland) and is validated with field observations. Chapter 7 investigates the use of ENVISAT-ASAR data for agricultural applications in the region of Toulouse. The first part discusses the possibilities for classification of crops. The second part investigates the potential of the polarization ratio HH / VV to estimate the biomass of wheat. It is confirmed that there is a clear link between this ratio and the biomass of wheat, however, this relationship depends on many other factors and seems to be dependent on the experimental site. Therefore, more studies needs to be conducted. The findings of this study, as well as their prospects are outlined in greater detail in Chapter 8. To