Francois-Marie Breon

• Managing Director at Atomic Energy and Alternative Energies Commission

There is a growing interest in estimating urban CO2 emission from spaceborne imagery of the CO2 column-average dry-air mole fraction (XCO2). Emission estimation methods have been widely tested and applied to actual or synthetic images. However, there is still a lack of objective criteria for selecting images that are worth processing. This study an...

To effectively monitor highly heterogeneous urban CO2 emissions using atmospheric observations, there is a need to deploy cost-effective CO2 sensors at multiple locations within the city with sufficient accuracy to capture the concentration gradients in urban environments. These dense measurements could be used as input of an atmospheric inversion...

There is a growing interest for the study of greenhouse gas emissions over urban areas. In this context, a network for measuring greenhouse gas concentrations was set up in Paris in 2015. Since then, seven stations located in and around Paris and equipped with cavity ring-down spectrometers (CRDS) have been monitoring gas concentrations of differen...

To effectively monitor the highly heterogeneous urban CO2 emissions using atmospheric observations, there is a need to deploy cost-effective CO2 sensors at multiple locations within the city with sufficient accuracy to capture the concentration gradients in urban environments. Its measurements could be used as input of an atmospheric inversion syst...

There is a growing interest in estimating urban CO2 emission from space-borne imagery of XCO2. Emission estimation methods are already being tested and applied to actual or synthetic images. However, we still need automatic and standard methods, as well as objective criteria for selecting the images to be processed. This study shows the performance...

Existing CO2 emissions reported by city inventories usually lag in real-time by a year or more and are prone to large uncertainties. This study responds to the growing need for timely and precise estimation of urban CO2 emissions to support present and future mitigation measures and policies. We focus on the Paris metropolitan area, the largest urb...

Existing CO2 emissions reported by city inventories usually lag real-time by a year or more and are prone to large uncertainties. This study responds to the growing need for timely and precise estimation of urban CO2 emissions to support the present and future mitigation measures and policies. We focus on the Paris metropolitan area, the largest ur...

Mitigating anthropogenic methane emissions is one of the available tools for reaching the near term objectives of the Paris Agreement. Characterizing the isotopic signature of the methane plumes emitted by these sources is needed to improve the quantification of methane sources at the regional scale. Urbanized and industrialized regions such as the...

Correct representation of seasonal leaf dynamics is crucial for terrestrial biosphere models (TBMs), but many such models cannot accurately reproduce observations of leaf onset and senescence. Here we optimised the phenology-related parameters of the ORCHIDEE TBM using satellite-derived Normalized Difference Vegetation Index data (MODIS NDVI v5) th...

Correct representation of seasonal leaf dynamics is crucial for Terrestrial Biosphere Models (TBMs), but many such models cannot accurately reproduce observations of leaf onset and senescence. Here we optimized the phenology-related parameters of the ORCHIDEE TBM using satellite-derived Normalized Difference Vegetation Index 5 data (MODIS NDVI v5)....

Carbon dioxide has exerted the largest portion of radiative forcing and surface temperature change over the industrial era, but other anthropogenic influences have also contributed. However, large uncertainties in total forcing make it difficult to derive climate sensitivity from historical observations. Anthropogenic forcing has increased between...

Atmospheric concentration measurements are used to adjust the daily to monthly budget of fossil fuel CO2 emissions of the Paris urban area from the prior estimates established by the Airparif local air quality agency. Five atmospheric monitoring sites are available, including one at the top of the Eiffel Tower. The atmospheric inversion is based on...

This paper investigates the scientific value of retrieving H218O and HDO columns in addition to H216O columns from high-resolution ground-based near-infrared spectra. We present a set of refined H216O, H218O, and HDO spectral windows. The retrieved H216O, H218O, and HDO columns are used for an a posteriori calculation of columnar δD and δ18O. We es...

A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observati...

Water stable isotopologues provide integrated tracers of the atmospheric water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recen...

This study presents the joint H216O and HDO retrieval from Infrared Atmospheric Sounding Interferometer (IASI) spectra over western Siberia. IASI is an instrument on board the MetOp-A European satellite. The global coverage of the instrument and the good signal-to-noise ratio allow us to provide information on δD over this remote region. We show th...

Although forest management is one of the instruments proposed to mitigate climate change, the relationship between forest management and canopy albedo has been ignored so far by climate models. Here we develop an approach that could be implemented in Earth system models. A stand-level forest gap model is combined with a canopy radiation transfer mo...

Atmospheric concentration measurements are used to adjust the daily to monthly budget of CO2 emissions from the AirParif inventory of the Paris agglomeration. We use 5 atmospheric monitoring sites including one at the top of the Eiffel tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model wit...

This paper investigates the possibility of retrieving isotopic composition of atmospheric water vapour from high-resolution ground based measurements of atmospheric transmittance spectra in the near-infrared region (4000-11 000 cm-1). Simulated measurements of atmospheric transmittance were analyzed in order to find clear spectral signatures of H21...

This study presents the joint H216O and HDO retrieval from Infrared Atmospheric Sounding Interferometer (IASI) spectra over the Western Siberia. IASI is an instrument on board the MetOp-A European satellite. The global coverage of the instrument and the good signal-to-noise ratio allow us to provide information on δ D over this remote region. We sh...

Despite an emerging body of literature linking canopy albedo to forest management, understanding of the process is still fragmented. We combined a stand-level forest gap model with a canopy radiation transfer model and satellite-derived model parameters to quantify the effects of forest thinning, that is removing trees at a certain time during the...

The net effect of aerosol Direct Radiative Forcing (DRF) is the balance between the scattering effect that reflects solar radiation back to space (cooling), and the absorption that decreases the reflected sunlight (warming). The amplitude of these two effects and their balance depends on the aerosol load, its absorptivity, the cloud fraction and th...

A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observati...

A possibility of retrieval of H2O and CH4 isotopologues concentration ratios from high resolution infrared measurements of atmospheric transmittance

Water stable isotopologues provide integrated tracers of the atmospheric water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. In spite of the presence of distinct spectral features of HDO molecule in TANSO-FTS/GOSAT thermal infrared spectra, the retrieval of vertical profiles of δHD...

The WSibIso program aims to investigate the water and carbon cycles in Western Siberia (55-70N, 55-90E) and their projected changes under a warming climate. Global warming is a major environmental issue and is expected to be greatest at high latitudes. In this context, Western Siberia is particularly vulnerable to temperature changes because of the...

While the rate of global warming averaged over the last 50 years amounts about 0.1°C per decade, boreal regions such as Siberia have been warming at considerably higher rates. The warming should affect the isotopic composition of meteoric water, with the temperature effect being stronger in high latitudes than in the global average. Unfortunately,...

CarbonSat was selected by ESA as a candidate for the 8 Earth Explorer Opportunity (EE8). The objective of the CarbonSat mission is to determine natural and anthropogenic sources and sinks of the two most important greenhouse gases, carbon dioxide and methane. The unique features of the CarbonSat mission concept are that it offers a combination of h...

The Bayesian framework of CO2 flux inversions permits estimates of the retrieved flux uncertainties. Here, the reliability of these theoretical estimates is studied through a comparison against the misfits between the inverted fluxes and independent measurements of the CO2 Net Ecosystem Exchange (NEE) made by the eddy covariance technique at local...

Water stable isotopes provide integrated tracers of the atmospheric water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recently d...

Spaceborne reflectance measurements from the POLDER instrument are used to study the specific directional signature close to the backscatter direction. The data analysis makes it possible to derive the extinction to backscatter ratio (EBR) which is the invert of the scattering phase function for an angle of 180° and is needed for a quantitative int...

In this study, we provide a comprehensive analysis of aerosol interaction with warm boundary layer clouds over the South-East Atlantic. We use aerosol and cloud parameters derived from MODIS observations, together with co-located CALIPSO estimates of the layer altitudes, to derive statistical relationships between aerosol concentration and cloud pr...

We describe a two-parameter model for the reflectance of snow and test it against multispectral and multi-angular observations. The first parameter of the model is proportional to the effective snow grain size. The second parameter accounts for the impact of soot and other pollutants on snow absorption. The model is analytical and is easily inverte...

In this study, we provide a comprehensive analysis of aerosol interaction with warm boundary layer clouds over the South-East Atlantic. We use aerosol and cloud parameters derived from MODIS observations, together with co-located CALIPSO estimates of the layer altitudes, to derive statistical relationships between aerosol concentration and cloud pr...

This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion and cement production. While much is known about these emissions, there is still much that is unknown about the details surrounding these emissions. This synthesis explores 5 our knowledge of these emissions in terms of why there is concern about them; how they are...

In her comment on our paper "Surface urban heat island across 419 global big cities"1, N. Schwarz raised several questions on our analyses relating surface urban heat island intensity (SUHII) to city division, city size and population intensity. We welcome this opportunity to clarify and reiterate a few important points made in our paper1 concernin...

This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion and cement production. While much is known about these emissions, there is still much that is unknown about the details surrounding these emissions. This synthesis explores our knowledge of these emissions in terms of why there is concern about them; how they are c...

Currently 70% of the world's forests are managed and this figure is likely to rise due to population growth and increasing demand for wood based products. Forest management has been put forward by the Kyoto-Protocol as one of the key instruments in mitigating climate change. For temperate and boreal forests, the effects of forest management on the...

HDO is long existing tool in climate sciences, and retrieved concentration of this molecule in the atmosphere can be used for adjusting general circulation models with embedded isotopomers. Retrieval of total columnar value of HDO in the atmosphere is possible using the TCCON FTIR spectrometers. However, satellite data can give better coverage of H...

Urban heat island is among the most evident aspects of human impacts on the earth system. Here we assess the diurnal and seasonal variation of surface urban heat island intensity (SUHII) defined as the surface temperature difference between urban area and suburban area measured from the MODIS. Differences in SUHII are analyzed across 419 global big...

Atmospheric CO₂ drives most of the greenhouse effect increase. One major uncertainty on the future rate of increase of CO₂ in the atmosphere is the impact of the anticipated climate change on the vegetation. Dynamic Global Vegetation Models (DGVM) are used to address this question. ORCHIDEE is such a DGVM that has proven usefu...

1] The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007–2009 observation...

Diamond dust (DD) refers to tiny ice crystals that form frequently in the Polar troposphere under clear sky conditions. They provide surfaces for chemical reactions and scatter light. We have measured the specific surface area (SSA) of DD at Barrow in March-April 2009. We have also measured its chemical composition in mineral and organic ions, diss...

Horizontally oriented plates in clouds generate a sharp specular reflectance signal in the glint direction, often referred to as "subsun". This signal (amplitude and width) may be used to analyze the relative area fraction of oriented plates in the cloud top layer and their characteristic tilt angle to the horizontal. We make use of spaceborne meas...

Atmospheric CO₂ drives most of the greenhouse effect increase and one major uncertainty on the future rate of increase of CO₂ in the atmosphere is the impact of the anticipated climate change on the vegetation. Dynamic Global Vegetation Models (DGVM) are used to address this question. ORCHIDEE is such a DGVM that has proven us...

Instruments dedicated to aerosol monitoring are recently available and the POLDER (POLarization and Directionality of the Earth's Reflectances) instrument on board the PARASOL (Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) mission is one of them. By measuring the spectral, angular and pol...

The aerosol remote sensing from space has started in the 1980's using observations provided by geostationary satellites or by polar orbiting platforms not specifically designed for observing aerosols. As a result, the number of retrieved parameters was limited and retrievals in the visible restricted over ocean. Over land, because of the important...

Samples of precipitation and atmospheric water vapor were collected together with shallow firn/ice cores as part of the new deep drilling project in northwest Greenland: the NEEM project. These samples were analyzed for their isotope composition to understand the processes affecting the climatic signal archived in the water stable isotope records f...

We explore the potential of tree-ring cellulose δ18O and δ13C records for reconstructing climate variability in the southeast Tibetan Plateau. Our sampling strategy was designed to investigate intra and inter-tree variability, and the effects of the age of tree on δ18O variation. We show that intra-tree δ13C and δ18O variability is negligible, and...

There is a crucial and urgent need to quantify and monitor anthropogenic fossil fuel emissions of CO2. Spaceborne measurements, such as those from GOSAT or the forthcoming OCO-2, or other space missions in preparation, could provide the necessary information, in particular over regions with few in-situ measurements of atmospheric concentration are...

In the context of rising greenhouse gas concentrations, and the potential feedbacks between climate and the carbon cycle, there is an urgent need to monitor the exchanges of carbon between the atmosphere and both the ocean and the land surfaces. In the so-called top-down approach, the surface fluxes of CO2 are inverted from the observed spatial and...

This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total...

We estimatethenorthernhemisphere(NH)terrestrialcarbon sink bycomparingfourrecentatmosphericinversionswith land-based Caccountingdataforsixlargenorthernregions. The meanNHterrestrialCO2 sink fromtheinversionmodelsis 1.7 PgCyear1 over theperiod2000 2004. Theuncertaintyof this estimateisbasedonthetypicalindividual(1-sigma) precision ofoneinversion(0.9...

In the context of raising greenhouse gas concentrations, and the potential feedbacks between climate and the carbon cycle, there is an urgent need to monitor the exchanges of carbon between the atmosphere and both the ocean and the land surfaces. In the so-called top-down approach, the surface fluxes of CO2 are inverted from the observed spatial an...

Aerosol interaction with clouds is the main uncertainty for the quantification of the anthropogenic forcing on climate. The first step of the so-called ``aerosol indirect effect'' is the change of cloud droplet size distribution when seeded by anthropogenic aerosols. Satellite data provide the density and diversity of observations needed for a stat...

Spaceborne remote sensing can be used to retrieve the atmospheric composition and complement the surface or airborne measurement networks. In recent years, a lot of attention has been placed on the monitoring of carbon dioxide for an estimate of surface fluxes from the observed spatial and temporal gradients of its concentration. Although other tec...

Despite their primary contribution to climate change, there are still large uncertainties on the sources and sinks of the main greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). A better knowledge of these sources is necessary to understand the processes that control them and therefore to predict their variations. Indeed...

The MODIS instruments have been flying onboard the Terra and Aqua platforms and acquire Earth observation data since early 2000 and mid 2002. Data processing allows the monitoring of the land cover dynamic. Here, a data processing scheme is described to generate Earth reflectance and emissivity time series at a sub-kilometer spatial resolution and...

The PARASOL instrument provides polarization measurements of the Earth's reflectance. Data processing of these measurements leads to a large and representative dataset of Bidirectional Polarization Distribution Functions (BPDF) for a wide range of surface cover. All surfaces show a similar pattern of the polarized reflectances, with very little pol...

The MODerate resolution Imaging Spectroradiometer (MODIS) retrieves aerosol optical depth (AOD) over land and ocean, and information on particle size over ocean, only. It succeeds due to its relatively fine spatial resolution of 500 m at nadir and broad spectral range from 0.47 µm to 2.13 µm. While the global scientific community has made excellent...

This paper quantifies the value added by the Greenhouse gases Observing SATellite (GOSAT) to numerical models of the global carbon cycle for the estimation of CO2 surface fluxes. The metric used here is the theoretical uncertainty reduction, defined as one minus the ratio of the posterior flux uncertainty to the prior ones. Our results indicate tha...

OCO and GOSAT will likely bring a wealth of accurate total column CO2 measurements that will allow the estimation of CO2 sources and sinks from space. Meanwhile even more advanced measurement concepts are being investigated for the next generation of instruments, such as the CO2 lidar A-SCOPE. Despite numerous attempts to simulate the benefit of re...

The so-called Vegetation Red-Edge (VRE), a sharp increase in the reflectance around $700 nm$, is a characteristic of vegetation spectra, and can therefore be used as a biomarker if it can be detected in an unresolved extrasolar Earth-like planet integrated reflectance spectrum. Here we investigate the potential for detection of vegetation spectra d...

Vertically-resolved attenuated backscatter from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission and Aerosol Optical Thickness (AOT)from Moderate-resolution Imaging Spectroradiometer (MODIS) are used to characterize the Saharan dust outflow over the Atlantic and to evaluate results from a global chemical and t...

It has been recognized recently that the future progress in aerosol knowledge should be associated with the integration of data from an increasing number of aerosol information sources, including diverse satellite and ground based instruments, in situ measurements, transport model forecasts, etc. Such aerosol information integration should not be l...

In a previous paper, we described a procedure to correct the directional effects in AVHRR reflectance time series. The corrected measurements show much less high frequency variability than their original counterparts, which makes them suitable to study vegetation dynamics. The time series are used here to estimate the start and ending dates of the...

Europe has experienced a wide scale warming over the past decades and climate simulations predict further warming and changes in precipitation patterns during the 21st century. The winter of 2006–2007 has been exceptionally mild with averaged temperatures that may become the norm during the second half of the 21st century. Here we report on satelli...

The dispersion of pollutants from the huge Buncefield oil depot fire that occurred on 11 December 2005 is simulated using a regional Eulerian chemistry-transport model. We analyse the transport and mixing of the fire plume. We show that the hot plume never reached the ground. Instead, it pierced the thin wintertime boundary layer and was injected i...

An intercomparison of the aerosol optical thickness (AOT) at 550nm retrieved using different satellite instruments and algorithms based on the analysis of backscattered solar light is performed for a single scene over central Europe on October 13th, 2005. For the first time comparisons have been performed for as many as six instruments on multiple...

n this paper, we address the issues of the representation of boreal fires in a global chemistry and transport model (GEOS-Chem) as well as their contribution to the Arctic aerosol optical thickness and black carbon (BC) deposition, with a focus on the 2003 Russian fires. We use satellite observations from the MOPITT, POLDER and MODIS sensors to eva...

This paper analyzes new lidar measurements from space over regions of biomass burning activity. The height of the aerosol layers deduced from the lidar observations is compared to the mixing layer top diagnosed from numerical weather forecasts, to identify whether or not the aerosols are directly injected in the free troposphere. During July and Au...

[1] CO2 mixing ratio derived from spaceborne measurements of the Television Infrared Observation Satellite (TIROS-N) Operational Vertical Sounder (TOVS) instrument onboard NOAA-10 available for the time period 1987–1991 are evaluated against modeling results and aircraft measurements. The model simulations are based on two transport models and two...

NASA's Orbiting Carbon Observatory will monitor the atmospheric concentrations of carbon dioxide (CO2) along the satellite subtrack over the sunlit hemisphere of the Earth for more than 2 years, starting in late 2008. This paper demonstrates the application of a variational Bayesian formalism to retrieve fluxes at high spatial and temporal resoluti...

An inter-comparison study of the aerosol optical thickness (AOT) at 0.55 μm retrieved using different satellite instruments and algorithms based on the analysis of backscattered solar light is presented for a single scene over central Europe on October 13th, 2005. For the first time comparisons have been performed for as many as six instruments on...

We present a method for simultaneously retrieving aerosol and surface parameters from ground-based and satellite observations collocated in space and time. We show that a combination of down and up-looking observations provides sufficient measurement constraints for characterizing both aerosol and surface properties with minimal assumptions. In ord...

A method for simultaneously retrieving aerosol and surface parameters from ground based and satellite observations collocated in space and time is presented. The improvements in aerosol and surface reflectance characterization are discussed.

The large spatial and temporal variability of atmospheric aerosol load makes it a challenge to quantify aerosol effect on climate. This study is one of the first attempts to apply data assimilation for the analysis of global aerosol distribution. Aerosol optical thickness (AOT) observed from the Polarization and Directionality of the Earth Reflecta...

The Parasol (Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar) mission launched in Dec. 2004 by CNES is carrying a wide-field imaging radiometer/polarimeter designed to improve the knowledge of the radiative and microphysical properties of clouds and aerosols. It is flying in formation with...

Simultaneous AERONET measurements and aerosol retrievals from PARASOL and MODIS/Terra are compared. Advantages of each instrument are described; for instance PARASOL can detect non-spherical particles within the coarse mode, which is not the case of MODIS. Simulations of MODIS (PARASOL respectively) measurements from PARASOL (MODIS) inverted aeroso...

Anthropogenic aerosol emissions may increase cloud cover by up to 5%, resulting in a substantial net cooling of Earth's atmosphere.

Measurements of wind speed and direction from the NASA Scatterometer and ocean reflectance from the POLDER multidirectional radiometer are used for a quantitative analysis of the ocean glint intensity and shape. These two instruments have been flying on board the ADEOS satellite platform, which assures a very large data set of coincident measuremen...

This paper describes a correction of directional effects in AVHRR reflectance time series. The method relies on a priori directional signatures, in the red and near infrared, for various surface covers. The reflectance normalization is applied to the historical Pathfinder AVHRR Land (PAL) data set acquired between 1981 and 1999. The high frequency...