FluorMODleaf: A new leaf fluorescence emission model based on the PROSPECT model

A new model of chlorophyll a fluorescence emission by plant leaves, FluorMODleaf, is presented. It is an extension of PROSPECT, a widely used leaf optical properties model that regards the leaf as a pile of N absorbing and diffusing elementary plates. In FluorMODleaf, fluorescence emission of an infinitesimal layer of thickness dx is integrated over the entire elementary plate. The fluorescence source function is based on the excitation spectrum of diluted isolated thylakoids and on the emission spectra of isolated photosystems, PSI and PSII, which are the main pigment-protein complexes involved in the initial stages of photosynthesis. Scattering within the leaf is produced by multiple reflections within and between elementary plates. The input variables of FluorMODleaf are: the number of elementary plates N, also called leaf structure parameter, the total chlorophyll content Cab, the total carotenoid content Ccx, the equivalent water thickness Cw, and the dry matter content Cm (or leaf mass per area), as in the new PROSPECT-5, plus the σII/σI ratio referring to the relative absorption cross section of PSI and PSII, and the fluorescence quantum efficiency of PSI and PSII, τI and τII, that are introduced here as mean fluorescence lifetimes. The model, which considers the reabsorption of emitted light within the leaf, allows good quantitative estimation of both upward and downward apparent spectral fluorescence yield (ASFY) at different excitation wavelengths from 400 nm to 700 nm. It also emphasizes the role of scattering in fluorescence emission by leaves having high chlorophyll content

The French EO high spatial resolution hyperspectral dual mission - an update

More than 25 years of airborne imaging spectroscopy and spaceborne sensors such as Hyperion [1] or HICO [2] have clearly demonstrated the ability of such a remote sensing technique to produce value added information regarding surface composition and physical properties for a large variety of applications [3]. Scheduled missions such as EnMAP [4], HISUI [5] or PRISMA [6] prove the increased interest of the scientific community for such a type of remote sensing data. In France, after gathering a group of Science and Defence users of imaging spectrometry data (Groupe de Synthèse Hyperspectral, GSH [7]) to establish an up-to-date review of possible applications, define instrument specifications required for accurate, quantitative retrieval of diagnostic parameters, and identify fields of application where imaging spectrometry is a major contribution, CNES (French Space Agency) decided a pre-phase A study for an hyperspectral mission concept called HYPXIM (HYPerspectral-X IMagery), the main fields of applications of which were to be vegetation, coastal and inland waters, geosciences, urban environment, atmospheric sciences, cryosphere and Defence. During this pre-phase A, the feasibility of such a platform was evaluated, based on specific studies supported by Defence and a more accurate definition of reference radiances and instrument characteristics. Results also pointed to applications where high spatial resolution was necessary and would not be covered by the other foreseen hyperspectral missions. For example, in the case of ecosystem studies, it is generally agreed that many model variables and processes are not accurately represented and that upcoming sensors with improved spatial and spectral capabilities, such as higher resolution imaging spectrometers, are needed to further improve the quality and accuracy of model variables [8, 9]. The growing interest for urban environment related applications also emphasized the need for an increased spatial resolution [10, 11]. Finally, short revisit time is an issue for security and Defense as well as crisis monitoring. Table 1 summarizes the Science and Defence mission requirements at the end of pre-phase A. Two instrument designs were proposed by the industry (EADS-Astrium and Thales Alenia Space) based on these new requirements [12]: HYPXIM-Challenging, on a micro-satellite platform, with a 15 m pixel and HYPXIM-Performance, on a mini-satellite platform, with a 8 m pixel, and possible TIR hyperspectral capabilities. Both scenarios included a PAN camera with a 1.85 m pixel. Platform agility would allow for “on-event mode” with a 3-day revisit time. CNES decided to select HYPXIM-Performance, the system providing a higher spatial resolution (pixel ≤ 8 m, [13, 14]), but without TIR capabilities, for a phase A study [15]. This phase A was to start at the beginning of 2013 but is currently stopped due to budget constraints. An important part of the activities has been focusing on getting the French community more involved through various surveys and workshops in preparation for the CNES prospective meeting, an important step for the future of the mission. During this prospective meeting, which took place last March, decision was taken to keep HYPXIM alive as a mid-term (2020-2025) mission. The attendance at the recent workshop organized by the SFPT-GH (Société Française de Photogrammétrie et Télédétection, Groupe Hyperspectral) which gathered more than 90 participants from various field of application, including the industry (see http://www.sfpt.fr/hyperspectral for more details), demonstrates the interest and support of the French scientific community for a high spatial resolution imaging spectrometry mission

Inversion of the PROSPECT + SAIL canopy reflectance model from AVIRIS equivalent spectra : theoretical study

International audienc

Utilisation de la haute resolution spectrale pour l'etude des couverts vegetaux : developpement d'un modele de reflectance spectrale

* INRA, Centre de Recherche d'Avignon, Unite Regionale de Documentation, Montfavet Diffusion du document : INRA, Centre de Recherche d'Avignon, Unite Regionale de Documentation, Montfavet Diplôme : Dr. d'Universit

Prospect : a model of leaf optical properties spectra

International audienc

Estimating vegetation biophysical parameters by inversion of a reflectance model on high spectral resolution data

National audienc

Modeling canopy spectral properties to retrieve biophysical and biochemical characteristics

International audienc

Mesure et modélisation des propriétés optiques spectrales et directionnelles des feuilles

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Leaf optical properties: A state of the art

ABSTRACT – Although leaf optical properties encompas an extensive subject, reviews are rare and generally tackle questions closer to plant physiology than remote sensing. Different ways these properties are measured and used in inversion models to estimate leaf biophysical properties are described in this paper. We examine critically the most common methods according to the type of leaf material (broad leaves or needles), to the available measurements, and to the ensuing applications. This paper is intended to review the state-of-the-art of a domain that is of prime interest to optical remote sensing. As leaves represent the main surfaces of plant canopies where energy and gases are exchanged, their optical properties are essential to understanding the transport of photons within vegetation. Because of the importance of photosynthetic function, leaf optical properties have bee

The soil line concept in remote sensing

International audienc