A5009927105- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Meteorological Phenomena and Simulations
- Plant Water Relations and Carbon Dynamics
- Atmospheric chemistry and aerosols
- Cryospheric studies and observations
- Atmospheric Ozone and Climate
- Wind and Air Flow Studies
- Fluid Dynamics and Turbulent Flows
- Geophysics and Gravity Measurements
- Grey System Theory Applications
- Environmental and Agricultural Sciences
- Sustainability and Ecological Systems Analysis
- Arctic and Antarctic ice dynamics
- Peatlands and Wetlands Ecology
- Tropical and Extratropical Cyclones Research
- Ocean Waves and Remote Sensing
- Fluid Dynamics and Vibration Analysis
- Urban Heat Island Mitigation
- Image Processing and 3D Reconstruction
- Precipitation Measurement and Analysis
- Cholinesterase and Neurodegenerative Diseases
- Aeolian processes and effects
- Sustainable Agricultural Systems Analysis
- Moringa oleifera research and applications
Laboratoire des Sciences du Climat et de l'Environnement
2012-2023
European Centre for Medium-Range Weather Forecasts
2023
Joint Research Centre
1998-2022
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2022
CEA Paris-Saclay
2022
Centre National de la Recherche Scientifique
1998-2022
Université de Versailles Saint-Quentin-en-Yvelines
2010-2022
Université Félix Houphouët-Boigny
2022
University of Bern
2008-2013
Institut Pierre-Simon Laplace
2009-2010
Abstract Emissions into the atmosphere from human activities show marked temporal variations, inter-annual to hourly levels. The consolidated practice of calculating yearly emissions follows same allocation underlying annual statistics. However, might not reflect heavy pollution episodes, seasonal trends, or any time-dependant atmospheric process. This study develops high-time resolution profiles for air pollutants and greenhouse gases co- emitted by anthropogenic sources in support...
We describe a system for constraining the spatial distribution of fossil fuel emissions CO 2 . The is based on modified Kaya identity which expresses as product areal population density, per capita economic activity, energy intensity economy, and carbon energy. apply methodology data assimilation to constrain such model with various observations, notably, statistics national nightlights population. hence produce global, annual emission field at 0.25° resolution. Our smoother than that...
We present the concept of Carbon Cycle Data Assimilation System and describe its evolution over last two decades from an assimilation system around a simple diagnostic model terrestrial biosphere to for calibration initialization land component comprehensive Earth model. critically review capability this modeling framework integrate multiple data streams, assess their mutual consistency with model, reduce uncertainties in simulation carbon cycle, provide, traceable manner, reanalysis...
Abstract. Large uncertainties in land surface models (LSMs) simulations still arise from inaccurate forcing, poor description of heterogeneity (soil and vegetation properties), incorrect model parameter values incomplete representation biogeochemical processes. The recent increase the number type carbon cycle-related observations, including both situ remote sensing measurements, has opened a new road to optimize parameters via robust statistical model–data integration techniques, order...
Abstract. Simulations of carbon fluxes with terrestrial biosphere models still exhibit significant uncertainties, in part due to the uncertainty model parameter values. With advent satellite measurements solar induced chlorophyll fluorescence (SIF), there exists a novel pathway for constraining simulated and We investigate utility SIF gross primary productivity (GPP). As first test we assess whether simulations are sensitive important parameters model. at wavelength 755 nm by Carbon-Cycle...
Abstract. This paper presents the assimilation of solar-induced chlorophyll fluorescence (SIF) into a terrestrial biosphere model to estimate gross uptake carbon through photosynthesis (GPP). We use BETHY-SCOPE simulate both GPP and SIF using process-based formulation, going beyond simple linear scaling between two. then satellite data from Orbiting Carbon Observatory-2 (OCO-2) for 2015 in system constrain biophysical parameters GPP. The results considerable improvement fit observed SIF,...
Abstract Predicting terrestrial carbon, C, budgets and carbon‐climate feedbacks strongly relies on our ability to accurately model interactions between vegetation, C water cycles, the atmosphere. However, fluxes simulated by global, process‐based biosphere models (TBMs) remain subject large uncertainties, partly due unknown or poorly calibrated parameters. This is because TBMs have not routinely been confronted against cycle related datasets within a statistical data assimilation (DA)...
This paper combines an atmospheric transport model and a terrestrial ecosystem to estimate gross primary productivity (GPP) net (NEP) of the land biosphere. Using CO 2 observations in Carbon Cycle Data Assimilation System (CCDAS) we global GPP 146 ± 19 GtC/yr. However, current observing network cannot distinguish this best from different assimilation experiment yielding 117 Spatial estimates agree with data‐driven extratropics but are overestimated poorly observed tropics. The uncertainty...
Understanding the environmental and biotic drivers of respiration at ecosystem level is a prerequisite to further improve scenarios global carbon cycle. In this study we investigated relevance physiological phenology, defined as seasonal changes in plant properties, for explaining temporal dynamics (RECO) deciduous forests. Previous studies showed that empirical RECO models can be substantially improved by considering dependency on short-term productivity (e.g., daily gross primary...
Abstract. The synthesis of model and observational information using data assimilation can improve our understanding the terrestrial carbon cycle, a key component Earth's climate–carbon system. Here we provide framework for combining observations solar-induced chlorophyll fluorescence (SIF) process-based to estimates uptake or gross primary production (GPP). We then quantify assess constraint SIF provides on uncertainty in global GPP through process parameters an error propagation study. By...
Wetlands are a major source of methane (CH4) and contribute between 30 40% to the total CH4 emissions. Wetland emissions depend on temperature, water table depth, both quantity quality organic matter. Global warming will affect these three drivers methanogenesis, raising questions about feedbacks natural production climate change. Until present large-scale response wetland has been investigated with land-surface models that have produced contrasting results. Here, we produce novel global...
Abstract The rapid polar sea ice retreat and its drivers are challenging still unresolved questions in climate change research. In particular, the relationship between near-surface wind speed extent remains unclear for two main reasons: (1) observed speeds over Polar Regions very sparse, (2) simulated winds by models dependent on subjective parameterizations of boundary layer stratification, ultimately leading to large uncertainty. Here, we use observation-based data (passive microwave...
CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 36:153-168 (2008) - DOI: https://doi.org/10.3354/cr00734 Heat waves across Europe by end of 21st century: multiregional climate simulations Brigitte Koffi1,3,*, Ernest Koffi2,3 1WSL, Swiss Federal Institute, PO Box 96, 1015 Lausanne, Switzerland 2Institute Applied Physics, University Bern, 3012 3Present address: Laboratoire des...
Abstract. This paper investigates the relationship between heterogeneity of terrestrial carbon cycle and optimal design observing networks to constrain it. We combine methods quantitative network carbon-cycle data assimilation a hierarchy increasingly heterogeneous descriptions European biosphere as indicated by increasing diversity plant functional types. employ three types observations, flask measurements CO2 concentrations, continuous pointwise flux. show that flux are extremely efficient...
2025 started with the launch of H-Europe project IM4CA to enhance quantification and understanding methane emissions sinks. A consortium 25 partners joins forces investigate pressing questions about evolution atmospheric levels in recent decades, reduce uncertainty future projections design efficient solutions for monitoring mitigating outside Europe. It will build new measurement modelling infrastructure improved progress toward short- long-term emission reduction targets, a prominent role...
Abstract. We evaluate the capability of global atmospheric transport model TM5 to simulate boundary layer dynamics and associated variability trace gases close surface, using radon (222Rn). Focusing on European scale, we compare height (BLH) in with observations from National Oceanic Atmospheric Admnistration (NOAA) Integrated Global Radiosonde Archive (IGRA) also ceilometer lidar (light detection ranging) BLH retrievals at two stations. Furthermore, simulations 222Rn activity...
Numerous numerical models are developed to predict long-range transport of hazardous air pollution in connection with accidental releases. When evaluating and improving such a model, it is important detect uncertainties connected the meteorological input data. A Lagrangian dispersion Severe Nuclear Accident Program, used here investigate effect errors data due analysis error. An ensemble forecast, produced at European Centre for Medium-Range Weather Forecasts, then as model input. The...
Abstract. The sensitivity of the process parameters Biosphere Energy Transfer HYdrology (BETHY) model to choices atmospheric concentration network, high frequency terrestrial fluxes, and choice flux measurement network is investigated by using a carbon cycle data assimilation system. We use BETHY-generated fluxes as proxy measurements. Results show that monthly mean or low-frequency observations CO2 provide strong constraints on relevant for net (NEP) but only weak controlling gross fluxes....
Abstract. We investigate the utility of satellite measurements chlorophyll fluorescence (Fs) in constraining gross primary productivity (GPP). ingest Fs into Carbon-Cycle Data Assimilation System (CCDAS) which has been augmented by component Soil Canopy Observation, Photochemistry and Energy fluxes (SCOPE) model. CCDAS simulates well patterns suggesting combined model is capable ingesting these measurements. However simulated insensitive to key parameter controlling GPP, carboxylation...
We use a carbon-cycle data assimilation system to estimate the terrestrial biospheric CO(2) flux until 2090. The sink increases rapidly and increase is stronger in presence of climate change. Using linearized model, we calculate uncertainty owing model parameters. large dominated by impact soil moisture on heterotrophic respiration. show that this can be greatly reduced constraining parameters with two decades atmospheric measurements.
Abstract. Large uncertainties in Land surface models (LSMs) simulations still arise from inaccurate forcing, incorrect model parameter values and incomplete representation of biogeochemical processes. The recent increase the number type carbon cycle related observations, including both situ remote sensing measurements, has opened a new road to optimize parameters via robust statistical model-data integration techniques, order reduce simulated fluxes stocks uncertainties. In this study we...
Abstract. In spite of the importance land ecosystems in offsetting carbon dioxide emissions released by anthropogenic activities into atmosphere, spatiotemporal dynamics terrestrial fluxes remain largely uncertain at regional to global scales. Over past decade, data assimilation (DA) techniques have grown for improving these simulated biosphere models (TBMs), optimizing model parameter values while also pinpointing possible parameterization deficiencies. Although joint multiple streams is...