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Your search keyword '"Vellinga, O. S."' showing total 4 results
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4 results on '"Vellinga, O. S."'

1. Inverse carbon dioxide flux estimates for the Netherlands

Author

Meesters, A. G. C. A., Tolk, L. F., Peters, W., Hutjes, R. W. A., Vellinga, O. S., Elbers, J. A., Vermeulen, A. T., van der Laan, S., Neubert, R. E. M., Meijer, H. A. J., Dolman, A. J., Earth and Climate, Hydrology and Geo-environmental sciences, Amsterdam Global Change Institute, Energy and Sustainability Research Institute Groni, and Isotope Research

Subjects
Meteorologie en Luchtkwaliteit, atmospheric co2, Meteorology and Air Quality, tower, exchange, emissions, transport models, Computational Geophysics: Model verification and validation, regional-scale, CO2 inversion, Climate Resilience, Klimaatbestendigheid, Biogeosciences: Carbon cycling (4806), Biogeosciences: Biosphere/atmosphere interactions (0315), Atmospheric Processes: Regional modeling (4316)
Abstract

[1] CO2 fluxes for the Netherlands and surroundings are estimated for the year 2008, from concentration measurements at four towers, using an inverse model. The results are compared to direct CO2 flux measurements by aircraft, for 6 flight tracks over the Netherlands, flown multiple times in each season. We applied the Regional Atmospheric Mesoscale Modeling system (RAMS) coupled to a simple carbon flux scheme (including fossil fuel), which was run at 10 km resolution, and inverted with an Ensemble Kalman Filter. The domain had 6 eco-regions, and inversions were performed for the four seasons separately. Inversion methods with pixel-dependent and -independent parameters for each eco-region were compared. The two inversion methods, in general, yield comparable flux averages for each eco-region and season, whereas the difference from the prior flux may be large. Posterior fluxes co-sampled along the aircraft flight tracks are usually much closer to the observations than the priors, with a comparable performance for both inversion methods, and with best performance for summer and autumn. The inversions showed more negative CO2 fluxes than the priors, though the latter are obtained from a biosphere model optimized using the Fluxnet database, containing observations from more than 200 locations worldwide. The two different crop ecotypes showed very different CO2 uptakes, which was unknown from the priors. The annual-average uptake is practically zero for the grassland class and for one of the cropland classes, whereas the other cropland class had a large net uptake, possibly because of the abundance of maize there. © 2012. American Geophysical Union. All Rights Reserved.

Published
2012
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2. Regional carbon dioxide and energy fluxes from airborne observations using flight-path segmentation based on landscape characteristics.

Author

Vellinga, O. S., Gioli, B., Elbers, J. A., Holtslag, A. A. M., Kabat, P., and Hutjes, R. W. A.

Subjects
CARBON dioxide & the environment, AIR quality & the environment, AIR pollution, AIRBORNE infection, AIR microbiology, SANITARY landfills
Abstract

This paper presents an analysis of regional fluxes obtained with a small aircraft over heterogeneous terrain in the south-west of France, during the large scale field experiment CERES'07. We use a method combining variable flight-path segmentation with basic airborne footprint analysis. The segmentation is based on topography, land use and soil type, using a.o. satellite imagery and digital maps. The segments are delineated using an average footprint length, based on all flights, and segment lengths, which are variable in space but not in time. The method results in segment averaged carbon and energy fluxes, which are shown to be representative of regional fluxes. Our analysis is focussed on carbon dioxide, heat and evaporative fluxes around solar noon. We will show that spatial and seasonal variations in the fluxes can be linked to the underlying landscape. In addition, a comparison between the airborne data and ground flux data is made to support our results. However, due to the incompleteness of ground data for some predominant vegetation types (even in such a data dense context), upscaling of ground data to regional fluxes was not possible. Without the comparison, we are still able to demonstrate that aircraft can provide direct and meaningful estimates of regional fluxes of energy and carbon dioxide. [ABSTRACT FROM AUTHOR]

Published
2010
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3. Regional carbon dioxide and energy fluxes from airborne observations using flight-path segmentation based on landscape characteristics.

Author

Vellinga, O. S., Hutjes, R. W. A., Elbers, J. A., Holtslag, A. A. M., and Kabat, P.

Subjects
CARBON dioxide, AIR pollution, SCIENTIFIC observation, LANDSCAPES, FIELD research, INCOMPLETENESS theorems
Abstract

This paper presents an analysis of regional fluxes obtained with a small aircraft over heterogeneous terrain in the South West of France, during the large scale field experiment CERES'07. We use a method combining variable flight-path segmentation with basic airborne footprint analysis. The segmentation is based on topography, land use and soil type, using a.o. satellite imagery and digital maps. The segments are delineated using an average footprint length, based on all flights, and segment lengths, which are variable in space but not in time. The method results in segment averaged carbon and energy fluxes, which are shown to be representative of regional fluxes. Our analysis is focussed on the carbon dioxide, heat and evaporative fluxes around solar noon. We will show that spatial and seasonal variations in the fluxes can be linked to the underlying landscape. In addition, a comparison between the airborne data and ground flux data is made to support our results. However, due to the incompleteness of ground data for some predominant vegetation types (even in such a data dense context), upscaling of ground data to regional fluxes was not possible. Without the comparison, we are still able to demonstrate that aircraft can provide direct and meaningful estimates of regional fluxes of energy and carbon dioxide. [ABSTRACT FROM AUTHOR]

Published
2009
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4. Mesoscale modeling of the CO2 interactions between the surface and the atmosphere applied to the April 2007 CERES field experiment.

Author

Sarrat, C., Noilhan, J., Lacarrére, P., Dolman, A. J., Gerbig, C., Elbers, J. A., Vellinga, O. S., Gioli, B., Miglietta, F., Neininger, B., Lauvaux, T., Ciais, P., Ramonet, M., Ceschia, E., and Bonnefond, J. M.

Subjects
CALIBRATION, ERRORS & omissions insurance, FIELD research, SIMULATION methods & models
Abstract

The paper describes a numerical interpretation of the April 2007 CarboEurope Regional Experiment Strategy (CERES) campaign, devotedto the study of CO2 cycle at the regional scale. The four consecutive clear sky days with intensive observations of CO2 concentration, fluxes at the the surface and in the boundary layer have been simulated with the Meso-NH mesoscale model. Aircraft observations of CO2 have been used to identify surface modelling errors and to calibrate the CO2 components of the surface model. After this calibration, the paper describes a systematic comparison of the model outputs with all the data collected during CERES, in April 2007. As a conclusion, an example of CO2 budgeting from the mesoscale model is given. [ABSTRACT FROM AUTHOR]

Published
2009
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