Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Plant functional type classification for earth system models: results from the European Space Agency's Land Cover Climate Change Initiative
Poulter, B. ; MacBean, N. ; Hartley, A. ; Khlystova, I. ; Arino, O. ; Betts, R. ; Bontemps, S. ; Boettcher, M. ; Brockmann, C. ; Defourny, P. ; Hagemann, S. ; Herold, M. ; Kirches, C. ; Lamarche, C. ; Lederer, D. ; Ottlé, C. ; Peters, M. ; Peylin, P. - \ 2015
Geoscientific Model Development 8 (2015). - ISSN 1991-959X - p. 2315 - 2328.
global vegetation model - world map - ecosystems - forests - cycle - uncertainties - resolution - feedbacks - phenology - database
Global land cover is a key variable in the earth system with feedbacks on climate, biodiversity and natural resources. However, global land cover data sets presently fall short of user needs in providing detailed spatial and thematic information that is consistently mapped over time and easily transferable to the requirements of earth system models. In 2009, the European Space Agency launched the Climate Change Initiative (CCI), with land cover (LC_CCI) as 1 of 13 essential climate variables targeted for research development. The LC_CCI was implemented in three phases: first responding to a survey of user needs; developing a global, moderate-resolution land cover data set for three time periods, or epochs (2000, 2005, and 2010); and the last phase resulting in a user tool for converting land cover to plant functional type equivalents. Here we present the results of the LC_CCI project with a focus on the mapping approach used to convert the United Nations Land Cover Classification System to plant functional types (PFTs). The translation was performed as part of consultative process among map producers and users, and resulted in an open-source conversion tool. A comparison with existing PFT maps used by three earth system modeling teams shows significant differences between the LC_CCI PFT data set and those currently used in earth system models with likely consequences for modeling terrestrial biogeochemistry and land–atmosphere interactions. The main difference between the new LC_CCI product and PFT data sets used currently by three different dynamic global vegetation modeling teams is a reduction in high-latitude grassland cover, a reduction in tropical tree cover and an expansion in temperate forest cover in Europe. The LC_CCI tool is flexible for users to modify land cover to PFT conversions and will evolve as phase 2 of the European Space Agency CCI program continues.
On the variation of regional CO2 exchange over temperate and boreal North America
Zhang, X. ; Gurney, K.R. ; Peylin, P. ; Chevallier, F. ; Law, R.M. ; Patra, P.K. ; Rayner, P.J. ; Roedenbeck, C. ; Krol, M.C. - \ 2013
Global Biogeochemical Cycles 27 (2013)4. - ISSN 0886-6236 - p. 991 - 1000.
atmospheric carbon-dioxide - terrestrial ecosystems - united-states - interannual variability - climate - forest - trends - drought - fluxes - land
Inverse-estimated net carbon exchange time series spanning two decades for six North American regions are analyzed to examine long-term trends and relationships to temperature and precipitation variations. Results reveal intensification of carbon uptake in eastern boreal North America (0.1 PgC/decade) and the Midwest United States (0.08 PgC/decade). Seasonal cross-correlation analysis shows a significant relationship between net carbon exchange and temperature/precipitation anomalies during the western United States growing season with warmer, dryer conditions leading reduced carbon uptake. This relationship is consistent with global change-type drought dynamics which drive increased vegetation mortality, increases in dry woody material, and increased wildfire occurrence. This finding supports the contention that future climate change may increase carbon loss in this region. Similarly, higher temperatures and reduced precipitation are accompanied by decreased net carbon uptake in the Midwestern United States toward the end of the growing season. Additionally, intensified net carbon uptake during the eastern boreal North America growing season is led by increased precipitation anomalies in the previous year, suggesting the influence of climate memory carried by regional snowmelt water. The two regions of boreal North America exhibit opposing seasonal carbon-temperature relationships with the eastern half experiencing a net carbon loss with near coincident increases in temperature and the western half showing increased net carbon uptake. The carbon response in the boreal west region lags the temperature anomalies by roughly 6months. This opposing carbon-temperature relationship in boreal North America may be a combination of different dominant vegetation types, the amount and timing of snowfall, and temperature anomaly differences across boreal North America.
Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions.
Peylin, P. ; Law, R.M. ; Gurney, K.R. ; Chevallier, F. ; Jacobsen, A.R. ; Maki, T. ; Niwa, Y. ; Patra, P.K. ; Peters, W. ; Rayner, P.J. ; Rödenbeck, C. ; Laan-Luijkx, I.T. van der; Zhang, X. - \ 2013
Biogeosciences 10 (2013). - ISSN 1726-4170 - p. 6699 - 6720.
interannual variability - dioxide exchange - transport model - sinks - fluxes - sensitivity - ocean - land - cycle - emissions
Atmospheric CO2 inversions estimate surface carbon fluxes from an optimal fit to atmospheric CO2 measurements, usually including prior constraints on the flux estimates. Eleven sets of carbon flux estimates are compared, generated by different inversions systems that vary in their inversions methods, choice of atmospheric data, transport model and prior information. The inversions were run for at least 5 yr in the period between 1990 and 2010. Mean fluxes for 2001-2004, seasonal cycles, interannual variability and trends are compared for the tropics and northern and southern extra-tropics, and separately for land and ocean. Some continental/basin-scale subdivisions are also considered where the atmospheric network is denser. Four-year mean fluxes are reasonably consistent across inversions at global/latitudinal scale, with a large total (land plus ocean) carbon uptake in the north (-3.4 Pg C yr(-1) (+/- 0.5 Pg C yr(-1) standard deviation), with slightly more uptake over land than over ocean), a significant although more variable source over the tropics (1.6 +/- 0.9 Pg C yr(-1)) and a compensatory sink of similar magnitude in the south (-1.4 +/- 0.5 Pg C yr(-1)) corresponding mainly to an ocean sink. Largest differences across inversions occur in the balance between tropical land sources and southern land sinks. Interannual variability (IAV) in carbon fluxes is larger for land than ocean regions (standard deviation around 1.06 versus 0.33 Pg C yr(-1) for the 1996-2007 period), with much higher consistency among the inversions for the land. While the tropical land explains most of the IAV (standard deviation similar to 0.65 Pg C yr(-1)), the northern and southern land also contribute (standard deviation similar to 0.39 Pg C yr(-1)). Most inversions tend to indicate an increase of the northern land carbon uptake from late 1990s to 2008 (around 0.1 Pg C yr(-1)), predominantly in North Asia. The mean seasonal cycle appears to be well constrained by the atmospheric data over the northern land (at the continental scale), but still highly dependent on the prior flux seasonality over the ocean. Finally we provide recommendations to interpret the regional fluxes, along with the uncertainty estimates.
The European land and inland water CO2, CO, CH4 and N2O balance between 2001 and 2005
Luyssaert, S. ; Abril, G. ; Andres, R. ; Bastviken, D. ; Bellassen, V. ; Bergamaschi, P. ; Bousquet, P. ; Chevallier, F. ; Ciais, P. ; Corazza, M. ; Dechow, R. ; Erb, K.H. ; Etiope, G. ; Fortems-Cheiney, A. ; Grassi, G. ; Hartmann, J. ; Jung, M. ; Lathiere, J. ; Lohila, A. ; Mayorga, E. ; Moosdorf, N. ; Njakou, D.S. ; Otto, J. ; Papale, D. ; Peters, W. ; Peylin, P. ; Raymond, P. ; Rodenbeck, C. ; Saarnio, S. ; Schulze, E.D. ; Szopa, S. ; Thompson, R. ; Verkerk, P.J. ; Vuichard, N. ; Wang, R. ; Wattenbach, M. ; Zaehle, S. - \ 2012
Biogeosciences 9 (2012)8. - ISSN 1726-4170 - p. 3357 - 3380.
north-atlantic oscillation - net ecosystem exchange - organic-carbon changes - atmospheric co2 - climate-change - nitrous-oxide - terrestrial biosphere - dioxide - fluxes - emissions
Globally, terrestrial ecosystems have absorbed about 30% of anthropogenic greenhouse gas emissions over the period 2000-2007 and inter-hemispheric gradients indicate that a significant fraction of terrestrial carbon sequestration must be north of the Equator. We present a compilation of the CO2, CO, CH4 and N2O balances of Europe following a dual constraint approach in which (1) a land-based balance derived mainly from ecosystem carbon inventories and (2) a land-based balance derived from flux measurements are compared to (3) the atmospheric data-based balance derived from inversions constrained by measurements of atmospheric GHG (greenhouse gas) concentrations. Good agreement between the GHG balances based on fluxes (1294 +/- 545 Tg C in CO2-eq yr(-1)), inventories (1299 +/- 200 Tg C in CO2-eq yr(-1)) and inversions (1210 +/- 405 Tg C in CO2-eq yr(-1)) increases our confidence that the processes underlying the European GHG budget are well understood and reasonably sampled. However, the uncertainty remains large and largely lacks formal estimates. Given that European net land to atmosphere exchanges are determined by a few dominant fluxes, the uncertainty of these key components needs to be formally estimated before efforts could be made to reduce the overall uncertainty. The net land-to-atmosphere flux is a net source for CO2, CO, CH4 and N2O, because the anthropogenic emissions by far exceed the biogenic sink strength. The dual-constraint approach confirmed that the European biogenic sink removes as much as 205 +/- 72 Tg C yr(-1) from fossil fuel burning from the atmosphere. However, This C is being sequestered in both terrestrial and inland aquatic ecosystems. If the C-cost for ecosystem management is taken into account, the net uptake of ecosystems is estimated to decrease by 45% but still indicates substantial C-sequestration. However, when the balance is extended from CO2 towards the main GHGs, C-uptake by terrestrial and aquatic ecosystems is offset by emissions of non-CO2 GHGs. As such, the European ecosystems are unlikely to contribute to mitigating the effects of climate change.
Letter tot the editor: Iconic CO2 Time Series at Risk
Houweling, S. ; Badawy, B. ; Baker, D.F. ; Basu, S. ; Belikov, D. ; Bergamaschi, P. ; Bousquet, P. ; Broquet, G. ; Butler, T. ; Canadell, J.G. ; Chen, J. ; Chevallier, F. ; Ciais, P. ; Collatz, G.J. ; Denning, S. ; Engelen, R. ; Enting, I.G. ; Fischer, M.L. ; Fraser, A. ; Gerbig, C. ; Gloor, M. ; Jacobson, A.R. ; Jones, D.B.A. ; Heimann, M. ; Khalil, A. ; Kaminski, T. ; Kasibhatla, P.S. ; Krakauer, N.Y. ; Krol, M. ; Maki, T. ; Maksyutov, S. ; Manning, A. ; Meesters, A. ; Miller, J.B. ; Palmer, P.I. ; Patra, P. ; Peters, W. ; Peylin, P. ; Poussi, Z. ; Prather, M.J. ; Randerson, J.T. ; Rockmann, T. ; Rodenbeck, C. ; Sarmiento, J.L. ; Schimel, D.S. ; Scholze, M. ; Schuh, A. ; Suntharalingam, P. ; Takahashi, T. ; Turnbull, J. ; Yurganov, L. ; Vermeulen, A. - \ 2012
Science 337 (2012)6098. - ISSN 0036-8075 - p. 1038 - 1040.
Importance of fossil fuel emission uncertainties over Europe for CO2 modeling: model intercomparison
Peylin, P. ; Houweling, S. ; Krol, M.C. ; Karstens, U. ; Rödenbeck, C. - \ 2011
Atmospheric Chemistry and Physics 11 (2011)13. - ISSN 1680-7316 - p. 6607 - 6622.
atmospheric transport models - part 1 - land - inversions - (co2)-c-14 - fluxes - sinks
Inverse modeling techniques used to quantify surface carbon fluxes commonly assume that the uncertainty of fossil fuel CO2 (FFCO2) emissions is negligible and that intra-annual variations can be neglected. To investigate these assumptions, we analyzed the differences between four fossil fuel emission inventories with spatial and temporal differences over Europe and their impact on the model simulated CO2 concentration. Large temporal flux variations characterize the hourly fields (~40 % and ~80 % for the seasonal and diurnal cycles, peak-to-peak) and annual country totals differ by 10 % on average and up to 40 % for some countries (i.e., the Netherlands). These emissions have been prescribed to seven different transport models, resulting in 28 different FFCO2 concentrations fields. The modeled FFCO2 concentration time series at surface sites using time-varying emissions show larger seasonal cycles (+2 ppm at the Hungarian tall tower (HUN)) and smaller diurnal cycles in summer (-1 ppm at HUN) than when using constant emissions. The concentration range spanned by all simulations varies between stations, and is generally larger in winter (up to ~10 ppm peak-to-peak at HUN) than in summer (~5 ppm). The contribution of transport model differences to the simulated concentration std-dev is 2–3 times larger than the contribution of emission differences only, at typical European sites used in global inversions. These contributions to the hourly (monthly) std-dev's amount to ~1.2 (0.8) ppm and ~0.4 (0.3) ppm for transport and emissions, respectively. First comparisons of the modeled concentrations with 14C-based fossil fuel CO2 observations show that the large transport differences still hamper a quantitative evaluation/validation of the emission inventories. Changes in the estimated monthly biosphere flux (Fbio) over Europe, using two inverse modeling approaches, are relatively small (less that 5 %) while changes in annual Fbio (up to ~0.15 % GtC yr-1) are only slightly smaller than the differences in annual emission totals and around 30 % of the mean European ecosystem carbon sink. These results point to an urgent need to improve not only the transport models but also the assumed spatial and temporal distribution of fossil fuel emission inventories.
Can we reconcile atmospheric estimates of the Northern terrestrial carbon sink with land-based accounting?
Ciais, P. ; Canadell, J. ; Luyssaert, S. ; Chevallier, F. ; Shvidenko, A. ; Poussi, Z. ; Jonas, M. ; Peylin, P. ; King, A. ; Schulze, E.D. ; Piao, S. ; Rödenbeck, C. ; Peters, W. ; Bréon, F.M. - \ 2010
Current Opinion in Environmental Sustainability 2 (2010)4. - ISSN 1877-3435 - p. 225 - 230.
co2 sources - dioxide exchange - transport - inversion - balance - fluxes - sensitivity - emissions
We estimate the northern hemisphere (NH) terrestrial carbon sink by comparing four recent atmospheric inversions with land-based C accounting data for six large northern regions. The mean NH terrestrial CO2 sink from the inversion models is 1.7 Pg C year-1 over the period 2000–2004. The uncertainty of this estimate is based on the typical individual (1-sigma) precision of one inversion (0.9 Pg C year-1) and is consistent with the min–max range of the four inversion mean estimates (0.8 Pg C year-1). Inversions agree within their uncertainty for the distribution of the NH sink of CO2 in longitude, with Russia being the largest sink. The land-based accounting estimate of NH carbon sink is 1.7 Pg C year-1 for the sum of the six regions studied. The 1-sigma uncertainty of the land-based estimate (0.3 Pg C year-1) is smaller than that of atmospheric inversions, but no independent land-based flux estimate is available to derive a ‘between accounting model’ uncertainty. Encouragingly, the top-down atmospheric and the bottom-up land-based methods converge to consistent mean estimates within their respective errors, increasing the confidence in the overall budget. These results also confirm the continued critical role of NH terrestrial ecosystems in slowing down the atmospheric accumulation of anthropogenic CO2
Importance of methane and nitrous oxide for Europe’s terrestrial greenhouse-gas balance
Schulze, E.D. ; Luyssaert, S. ; Ciais, P. ; Freibauer, A. ; Janssens, I.A. ; Soussana, J.F. ; Smith, P. ; Grace, J. ; Levin, I. ; Thiruchittampalam, B. ; Heimann, M. ; Dolman, A.J. ; Valentini, R. ; Bousquet, P. ; Peylin, P. ; Peters, W. ; Rödenbeck, C. ; Etiope, G. ; Vuichard, N. ; Wattenbach, M. ; Nabuurs, G.J. ; Poussi, Z. ; Nieschulze, J. ; Gash, J.H.C. - \ 2009
Nature Geoscience 2 (2009). - ISSN 1752-0894 - p. 842 - 850.
atmospheric methane - carbon budget - emissions - co2 - ecosystems - fluxes - soils - sink
Climate change negotiations aim to reduce net greenhouse-gas emissions by encouraging direct reductions of emissions and crediting countries for their terrestrial greenhouse-gas sinks. Ecosystem carbon dioxide uptake has offset nearly 10% of Europe's fossil fuel emissions, but not all of this may be creditable under the rules of the Kyoto Protocol. Although this treaty recognizes the importance of methane and nitrous oxide emissions, scientific research has largely focused on carbon dioxide. Here we review recent estimates of European carbon dioxide, methane and nitrous oxide fluxes between 2000 and 2005, using both top-down estimates based on atmospheric observations and bottom-up estimates derived from ground-based measurements. Both methods yield similar fluxes of greenhouse gases, suggesting that methane emissions from feedstock and nitrous oxide emissions from arable agriculture are fully compensated for by the carbon dioxide sink provided by forests and grasslands. As a result, the balance for all greenhouse gases across Europe's terrestrial biosphere is near neutral, despite carbon sequestration in forests and grasslands. The trend towards more intensive agriculture and logging is likely to make Europe's land surface a significant source of greenhouse gases. The development of land management policies which aim to reduce greenhouse-gas emissions should be a priority
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