Search results for "carbon flux"

Simulación de flujos de carbono terrestres mediante teledetección y modelización de ecosistemas

2019

[EN] The main goal of this thesis is the establishment of a framework to analyze the forest ecosystems in peninsular Spain in terms of their role in the carbon cycle. In particular, the carbon fluxes that they exchange with atmosphere are modeled to evaluate their potential as carbon sinks and biomass reservoirs. The assessment of gross and net carbon fluxes is performed at 1-km spatial scale and on a daily basis using two different ecosystem models, Monteith and BIOME-BGC, respectively. These models are driven by a combination of satellite and ground data, part of the latter being also employed as a complementary data source and in the validation process. [ES] El objetivo principal de esta…

Simulació de fluxos de carboni terrestres mitjançant teledetecció i modelització d'ecosistemes

2018

The main goal of this thesis is the establishment of a framework to analyze the Spanish forest ecosystems in terms of their role in the carbon cycle. In particular, the carbon fluxes that they exchange with atmosphere are modeled to evaluate their potential as carbon sinks and biomass reservoirs. Gross fluxes are estimated by a production efficiency model relying on the Monteith’s approach. The emphasis is put in characterizing the water stress effects on the light use efficiency and, eventually, on the GPP. Six alternatives are evaluated. Among them, the ones using the ratio between the MODIS actual and potential evapotranspiration, and the soil moisture from SMOS demonstrate that it is po…

Global and time-resolved monitoring of crop photosynthesis with chlorophyll fluorescence

2014

Guanter, Luis et al.

Monitoring water and carbon fluxes at fine spatial scales using HyspIRI-like measurements

2012

Remotely sensed observations in the visible to the shortwave infrared (VSWIR) and thermal infrared (TIR) regions of the electromagnetic spectrum can be used synergistically to provide valuable products of land surface properties for reliable assessments of carbon and water fluxes. The high spatial, spectral and temporal resolution VSWIR and TIR observations provided by the proposed Hyperspectral - InfraRed (HyspIRI) mission will enable a new era of global agricultural monitoring, critical for addressing growing issues of food insecurity. To enable predictions at fine spatial resolution (<100m), modeling efforts must rely on a combination of high-frequency temporal and highresolution spa…

Storage and release of fossil organic carbon related to weathering of sedimentary rocks

2007

International audience; The biogeochemical carbon cycle, which plays an undeniable role in global climate change, is defined both by the size of carbon reservoirs (such as the atmosphere, biomass, soil and bedrock) and the exchange between them of various mineral and organic carbon forms. Among these carbon forms, fossil organic carbon (FOC) (i.e., the ancient organic matter stored in sedimentary rocks) is widely observed in modern environments but is not included in the supergene carbon budget. Using a digitized map of the world and an existing model of CO2 consumption associated with rock weathering, we establish the global distribution of FOC stored in the first meter of sedimentary rock…

Toward a better understanding of fish‐based contribution to ocean carbon flux

2021

Fishes are the dominant vertebrates in the ocean, yet we know little of their contribution to carbon export flux at regional to global scales. We synthesize the existing information on fish-based carbon flux in coastal and pelagic waters, identify gaps and challenges in measuring this flux and approaches to address them, and recommend research priorities. Based on our synthesis of passive (fecal pellet sinking) and active (migratory) flux of fishes, we estimated that fishes contribute an average (± standard deviation) of about 16.1% (± 13%) to total carbon flux out of the euphotic zone. Using the mean value of model-generated global carbon flux estimates, this equates to an annual flux of 1…

Caractérisation expérimentale de la variabilité phénotypique du système racinaire nodulé de génotypes contrastés de pois (Pisum sativum L.), en phase…

2013

One of the challenges in plant breeding pea is to offer adapted genotypes to non-optimal environmental conditions. One of the factors limiting the agronomic performance of the pea is related to the environment plant sensitivity. Nodulated root system traits determine this sensitivity. The characterization of phenotypic traits combinations of the nodulated root system in different peas genotypes is interesting to suggest new plant breeding traits. The objective of this work was to experimentally characterize the phenotypic variability of the nodulated root system of 10 pea genotypes. The analysis was conducted under controlled conditions. The plants were grown in the absence of nitrates. Phe…

Scaling carbon fluxes from eddy covariance sites to globe: synthesis and evaluation of the FLUXCOM approach

2020

FLUXNET comprises globally distributed eddy-covariance-based estimates of carbon fluxes between the biosphere and the atmosphere. Since eddy covariance flux towers have a relatively small footprint and are distributed unevenly across the world, upscaling the observations is necessary to obtain global-scale estimates of biosphere–atmosphere exchange. Based on cross-consistency checks with atmospheric inversions, sun-induced fluorescence (SIF) and dynamic global vegetation models (DGVMs), here we provide a systematic assessment of the latest upscaling efforts for gross primary production (GPP) and net ecosystem exchange (NEE) of the FLUXCOM initiative, where different machine learning methods…

An Overview of the Regional Experiments for Land-Atmosphere Exchanges 2012 (Reflex 2012) Campaign

2015

The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy…

2016

Gianluca Tramontana was supported by the GEOCARBON EU FP7 project (GA 283080). Dario Papale, Martin Jung and Markus Reichstein acknowledge funding from the EU FP7 project GEOCARBON (grant agreement no. 283080) and the EU H2020 BACI project (grant agreement no. 640176). Gustau Camps-Valls wants to acknowledge the support by an ERC Consolidator Grant with grant agreement 647423 (SEDAL). Kazuhito Ichii was supported by Environment Research and Technology Development Funds (2-1401) from the Ministry of the Environment of Japan and the JAXA Global Change Observation Mission (GCOM) project (no. 115). Christopher R. Schwalm was supported by National Aeronautics and Space Administration (NASA) gran…