R. Lopez-Lozano

R. Lopez-Lozano
French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH)

PhD.

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47
Publications
30,465
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1,646
Citations

Publications

Publications (47)
Article
The objective of this study is to evaluate the performances of a semi-empirical approach based on the Bayesian theory to retrieve Green Area Index (GAI) from multiple decametric satellites. It is designed to overcome some limitations in existing Radiative Transfer Model (RTM) inversion methods, including the high dimensionality of the inverse probl...
Article
Full-text available
With the widespread use of high-throughput phenotyping systems, growth process data are expected to become more easily available. By applying genomic prediction to growth data, it will be possible to predict the growth of untested genotypes. Predicting the growth process will be useful for crop breeding, as variability in the growth process has a s...
Article
Full-text available
Multispectral observations from unmanned aerial vehicles (UAVs) are currently used for precision agriculture and crop phenotyping applications to monitor a series of traits allowing the characterization of the vegetation status. However, the limited autonomy of UAVs makes the completion of flights difficult when sampling large areas. Increasing the...
Preprint
Full-text available
With the widespread use of high-throughput phenotyping systems, growth process data are expected to become more easily available. By applying genomic prediction to growth data, it will be possible to predict the growth of untested genotypes. Predicting the growth process will be useful for crop breeding, as variability in the growth process has a s...
Article
Full-text available
Early-stage plant density is an essential trait that determines the fate of a genotype under given environmental conditions and management practices. The use of RGB images taken from UAVs may replace the traditional visual counting in fields with improved throughput, accuracy, and access to plant localization. However, high-resolution images are re...
Preprint
Full-text available
Early-stage plant density is an essential trait that determines the fate of a genotype under given environmental conditions and management practices. The use of RGB images taken from UAVs may replace traditional visual counting in fields with improved throughput, accuracy and access to plant localization. However, high-resolution (HR) images are re...
Article
Full-text available
Plant responses to rising atmospheric carbon dioxide (CO2) concentrations, together with projected variations in temperature and precipitation will determine future agricultural production. Estimates of the impacts of climate change on agriculture provide essential information to design effective adaptation strategies, and develop sustainable food...
Article
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Statistical, data-driven methods are considered good alternatives to process-based models for the sub-national monitoring of cereal crop yields, since they can flexibly handle large datasets and can be calibrated simultaneously to different areas. Here, we assess the influence of several characteristics on the ability of these methods to forecast c...
Article
Full-text available
Accurate and timely observations of wheat phenology and, particularly, of heading date are instrumental for many scientific and technical domains such as wheat ecophysiology, crop breeding, crop management or precision agriculture. Visual annotation of the heading date in situ is a labour-intensive task that may become prohibitive in scientific and...
Article
Full-text available
Long timeseries of Earth observation data for the characterization of agricultural crops across large scales are of high interest to crop modelers, scientists, and decision makers in the fields of agricultural and environmental policy as well as crop monitoring and food security. They are particularly important for regression-based crop monitoring...
Preprint
Statistical, data-driven methods are considered good alternatives to process-based models for the sub-national monitoring of cereal crop yields since they can flexibly handle large datasets and can be calibrated simultaneously to different areas. In this study, we assess the influence of several characteristics on the ability of these methods to fo...
Article
Full-text available
This study assesses crop residues in the EU from major crops using empirical models to predict crop residues from yield statistics; furthermore it analyses the inter‐annual variability of those estimates over the period 1998‐2015, identifying its main drivers across Europe. The models were constructed based on an exhaustive collection of experiment...
Article
Full-text available
Temperature and precipitation are the most important factors responsible for agricultural productivity variations. In 2018 spring/summer growing season, Europe experienced concurrent anomalies of both. Drought conditions in central and northern Europe caused yield reductions up to 50% for the main crops, yet wet conditions in southern Europe saw yi...
Conference Paper
Full-text available
Europe experienced exceptional climate conditions in spring and summer 2018. The extreme drought in central and northern Europe heavily affected key socio-economic sectors. While, anomalous wet conditions in southern Europe favoured sectors such as agriculture triggering crop yield gains that partially offset the losses in central and northern Euro...
Article
Full-text available
The application of detailed process-oriented simulation models for gross primary production (GPP) estimation is constrained by the scarcity of the data needed for their parametrization. In this manuscript, we present the development and test of the assimilation of Moderate Resolution Imaging Spectroradiometer (MODIS) satellite Normalized Difference...
Article
Full-text available
Here we assess the quality and in-season development of European wheat (Triticum spp.) yield forecasts during low, medium, and high-yielding years. 440 forecasts were evaluated for 75 wheat forecast years from 1993–2013 for 25 European Union (EU) Member States. By July, years with median yields were accurately forecast with errors below ~2%. Yield...
Article
Full-text available
The MARS-Crop Yield Forecasting System (M-CYFS) is used since 1993 to forecast the yields of all major crops in the European Union (EU) based on gridded runs of the WOFOST crop model. Using 28 years of observation, from 1988 to 2015, we quantified the variability in crop yield reported by all 28 EU Member States (MS) that can be explained by each i...
Article
Full-text available
This paper presents an evaluation framework followed to identify cost-efficient alternatives to extend the MARS Crop Yield Forecasting System (MCYFS), run by the European Commission Joint Research Centre since 1992, to other main producing areas of the world: Eastern European Neighbourhood, Asia, Australia, South America and North America. These ne...
Technical Report
Full-text available
This report illustrates part of the results from the first two years of JRC biomass study, carried out in the context of the mandate on the provision to EC services of data and analysis on biomass flow, supply and demand on a long-term basis.
Article
After 15 years, the Système Pour l’Observation de la Terre (SPOT)-VEGETATION (VGT) program reached the end of its life inMay 2014 and was replaced by the Project for On-Board Autonomy-Vegetation (PROBA-V) mission. Exploiting the period of overlap between instruments, this study compares the normalized difference vegetation index (NDVI) of two instr...
Article
Full-text available
MODIS has been providing daily imagery for retrieving land surface properties with a spatial resolution 250m since the year 2000. In many places, this pixel size is closer to that of individual landscape elements, such as managed forest stands or crop fields, than those of time series more typically used in vegetation analyses (with pixel sizes ran...
Article
Full-text available
This study addresses the role of satellite Earth Observation (EO) indicators within an operational crop yield forecasting system for the European Union (EU) and neighbouring countries, by exploring the correlation between official yield statistics and indicators derived from fAPAR time-series at sub-national level for the period 1999–2012, and by i...
Article
The leaf area index (LAI), defined as half the total developed area of green photosynthetically active elements per unit horizontal ground area, is one of the key biophysical variables of vegetated surfaces. Optical devices developed to overcome the burden of time consuming, expensive and difficult to conduct sampling in tree canopies are based on...
Article
Full-text available
A processing of remotely-sensed Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) time series at 1-km spatial resolution is established to estimate sugarcane yield over the state of São Paulo, Brazil. It includes selecting adequate time series according to the signal spatial purity, using thermal time instead of calendar time and smo...
Article
Background and Aims: Most optical devices for indirect measurement of leaf area index (LAI) from canopy-transmitted light are tailored for homogeneous canopies, thus limiting their application to discontinuous canopies such as vertically trained vineyards. This study evaluates the influence of sun position on the reliability of LAI estimates provid...
Conference Paper
Full-text available
The European Commission requires in-season crop yield forecasts at a European level as part of the decision making process on market intervention and for policy support. For the past twenty years, the Monitoring Agricultural Resources (MARS) Unit of the European Commission Joint Research Centre (JRC) has operationally produced such forecasts using...
Article
Full-text available
The effect of canopy architecture in the estimation of biophysical parameters from remote sensing data in orchards is studied through the particular case of vineyard canopies. Two different approximations (1D and 3D models) are tested to estimate Leaf Area Index (LAI) from canopy reflectance in a total of 31 points within commercial field plots. Th...
Article
A detailed dynamic 3D architecture model coupled with a soil water balance model is used to explore the pertinence of 2D approximations of the row structure and describe the light regime and canopy photosynthesis in vineyard. The fraction of intercepted light (fIPAR), the fraction of illuminated leaf area (fILA) and the distribution of light intens...
Article
This study describes a technique to estimate green area index (GAI) of row crops from gap fraction measurements at 57.5° perpendicular to the row using downward looking digital photos. This particular directional configuration makes the gap fraction independent from leaf angle distribution and minimizes leaf clumping when plants overlap within the...
Article
Masting is the intermittent and synchronous production of large crops, but its relation to tree growth remains elusive despite the ecological relevance of mast seeding. The production of huge fruit crops has been linked to the accumulation and consumption of resources as nutrients and carbohydrates, but no conclusive assessment has supported this a...
Article
Full-text available
The inversion of canopy reflectance models is widely used for the retrieval of vegetation properties from remote sensing. However the accuracy of the estimates depends on a range of factors, most notably the realism with which the canopy is represented by the models and the possibility of introducing a priori knowledge on canopy characteristics to...
Article
The joint use of satellite imagery and digital soil maps derived from soil sampling is investigated in the present paper with the goal of proposing site-specific management units (SSMU) within a commercial field plot. Very high resolution Quickbird imagery has been used to derive leaf area index (LAI) maps in maize canopies in two different years....
Conference Paper
Full-text available
This study investigates the retrieval performances of LAI using radiative transfer model inversion. The SAIL and GEOSAIL models were used here to evaluate the impact of the complexity of canopy architecture on LAI estimation. The inversion of SAIL or GEOSAIL models was carried out using a look up table technique. Test data sets were generated with...
Article
A vineyard architecture model coupled with a soil water balance model is used to explore the links between vineyard reflectance in different scenarios of plant water stress, taking into account meteorological data, agricultural data and site specific information to produce virtual 3D scenes describing vineyard canopies. The ability of the model to...
Article
Full-text available
Leaf Area Index (LAI) retrieval performances from gap fraction measurements are investigated over vertically trained vineyards. A 3D vineyard model was constructed to analyze the influence of canopy architecture characteristics and light direction on LAI estimation. Results show that for specific directions – close to zenith and parallel to the row...
Article
The inversion of canopy reflectance models is a procedure widely employed for the retrieval of LAI from remote sensing. However the accuracy of the estimates depends on a range of factors, most notably the realism of the canopy representation of the models employed and the a priori knowledge of some vegetation characteristics. The objective of the...
Article
The influence of maize architectural characteristics on gap fraction (Po) is investigated based on a 4D canopy model. This model simulates maize canopies from few input variables: maximum leaf area per plant, maximum number of leaves, plant density, distance between rows, leaf orientation plasticity, maximum height of plant and plant growing stage....
Conference Paper
An assessment of water management in the Flumen District, Central Valley of the Ebro River Basin in Spain, using the remote sensing technique Surface Energy Balance Algorithm for Land (SEBAL) was performed. This assessment was based on the estimation of the actual ET (ETa) to compute net water volumes (Vn). This work extended the analysis by also c...
Article
Methods for chlorosis detection and physiological condition monitoring in Vitis vinifera L. through accurate chlorophyll a and b content (Cab) estimation at leaf and canopy levels are presented in this manuscript. A total of 24 vineyards were identified for field and airborne data collection with the Compact Airborne Spectrographic Imager (CASI), t...

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