Sitch, S., P. Friedlingstein, N. Gruber, S.D. Jones, G. Murray-Tortarolo, A. Ahlström, S.C. Doney, H. Graven, C. Heinze, C. Huntingford, S. Levis, P.E. Levy, M. Lomas, B. Poulter, N. Viovy, S. Zaehle, N. Zeng, A. Arneth, G. Bonan, L. Bopp, J.G. Canadell, F. Chevallier, P. Ciais, R. Ellis, M. Gloor, P. Peylin, S.L. Piao, C.L. Quéré, B. Smith, Z. Zhu, and R. Myneni. (2015). Recent trends and drivers of regional sources and sinks of carbon dioxide. Biogeosciences, 12.
Abstract: The land and ocean absorb on average just over half of the anthropogenic emissions of carbon dioxide (CO2) every year. These CO2 "sinks" are modulated by climate change and variability. Here we use a suite of nine dynamic global vegetation models (DGVMs) and four ocean biogeochemical general circulation models (OBGCMs) to estimate trends driven by global and regional climate and atmospheric CO2 in land and oceanic CO2 exchanges with the atmosphere over the period 1990–2009, to attribute these trends to underlying processes in the models, and to quantify the uncertainty and level of inter-model agreement. The models were forced with reconstructed climate fields and observed global atmospheric CO2; land use and land cover changes are not included for the DGVMs. Over the period 1990–2009, the DGVMs simulate a mean global land carbon sink of −2.4 ± 0.7 Pg C yr−1 with a small significant trend of −0.06 ± 0.03 Pg C yr−2 (increasing sink). Over the more limited period 1990–2004, the ocean models simulate a mean ocean sink of −2.2 ± 0.2 Pg C yr−1 with a trend in the net C uptake that is indistinguishable from zero (−0.01 ± 0.02 Pg C yr−2). The two ocean models that extended the simulations until 2009 suggest a slightly stronger, but still small, trend of −0.02 ± 0.01 Pg C yr−2. Trends from land and ocean models compare favourably to the land greenness trends from remote sensing, atmospheric inversion results, and the residual land sink required to close the global carbon budget. Trends in the land sink are driven by increasing net primary production (NPP), whose statistically significant trend of 0.22 ± 0.08 Pg C yr−2 exceeds a significant trend in heterotrophic respiration of 0.16 ± 0.05 Pg C yr−2 – primarily as a consequence of widespread CO2 fertilisation of plant production. Most of the land-based trend in simulated net carbon uptake originates from natural ecosystems in the tropics (−0.04 ± 0.01 Pg C yr−2), with almost no trend over the northern land region, where recent warming and reduced rainfall offsets the positive impact of elevated atmospheric CO2 and changes in growing season length on carbon storage. The small uptake trend in the ocean models emerges because climate variability and change, and in particular increasing sea surface temperatures, tend to counter\-act the trend in ocean uptake driven by the increase in atmospheric CO2. Large uncertainty remains in the magnitude and sign of modelled carbon trends in several regions, as well as regarding the influence of land use and land cover changes on regional trends.
Programme: 416
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Sanial V, van Beek P, Lansard B, Souhaut M, Kestenare E, d'Ovidio F, Zhou M, Blain S, . (2015). Use of Ra isotopes to deduce rapid transfer of sediment-derived inputs off Kerguelen
. Biogeosciences, 12(5), 1415–1430.
Abstract: KEOPS-2 Special Issue
Programme: 1077
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Sarma, V.V.S.S., A. Lenton, R. Law, N. Metzl, P.K. Patra, S. Doney, I.D. Lima, E. Dlugokencky, M. Ramonet, and V. Valsala. (2013). Biogeosciences, 10.
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. (2021). (Vol. 39).
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Marchaudon A, Cerisier J-C, Dunlop M W, Pitout F, Bosqued J-M, Fazakerley A N, . (2009). Shape, size, velocity and field-aligned currents of dayside plasma injections: a multi-altitude study
. Ann. Geophys., 27(3), 1251–1266.
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. (2008). A statistical approach for identifying the ionospheric footprint of magnetospheric boundaries from SuperDARN observations
. 0992-7689, 26(2), 305–314.
Abstract: Identifying and tracking the projection of magnetospheric regions on the high-latitude ionosphere is of primary importance for studying the Solar Wind-Magnetosphere-Ionosphere system and for space weather applications. By its unique spatial coverage and temporal resolution, the Super Dual Auroral Radar Network (SuperDARN) provides key parameters, such as the Doppler spectral width, which allows the monitoring of the ionospheric footprint of some magnetospheric boundaries in near real-time. In this study, we present the first results of a statistical approach for monitoring these magnetospheric boundaries. The singular value decomposition is used as a data reduction tool to describe the backscattered echoes with a small set of parameters. One of these is strongly correlated with the Doppler spectral width, and can thus be used as a proxy for it. Based on this, we propose a Bayesian classifier for identifying the spectral width boundary, which is classically associated with the Polar Cap boundary. The results are in good agreement with previous studies. Two advantages of the method are: the possibility to apply it in near real-time, and its capacity to select the appropriate threshold level for the boundary detection.
Programme: 911
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. (2015). Comprehensive laboratory and field testing of cavity ring-down spectroscopy analyzers measuring H2O, CO2, CH4 and CO
. Atmospheric Measurement Techniques Discussions, 8(4), 4219–4272.
Abstract: To develop an accurate measurement network of greenhouse gases, instruments in the field need to be stable and precise and thus require infrequent calibrations and a low consumption of consumables. For about ten years, cavity ring-down spectroscopy (CRDS) analyzers have been available that meet these stringent requirements for precision and stability. Here, we present the results of tests of CRDS instruments in the laboratory (47 instruments) and in the field (15 instruments). The precision and stability of the measurements are studied. We demonstrate that, thanks to rigorous testing, newer models generally perform better than older models, especially in terms of reproducibility between instruments. In the field, we see the importance of individual diagnostics during the installation phase, and we show the value of calibration and target gases that assess the quality of the data. Finally, we formulate recommendations for use of these analyzers in the field.
Programme: 416
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Rella C W, Chen H, Andrews A E, Filges A, Gerbig C, Hatakka J, Karion A, Miles N L, Richardson S J, Steinbacher M, Sweeney C, Wastine B, Zellweger C, . (2012). High accuracy measurements of dry mole fractions of carbon dioxide and methane in humid air
. Atmospheric Measurement Techniques, 5(4), 5823–5888.
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Hazan, L., J. Tarniewicz, M. Ramonet, O. Laurent, and A. Abbaris. (2016). Automatic processing of atmospheric CO2 and CH4 mole fractions at the ICOS Atmospheric Thematic Center. Atmos. Meas. Tech., .
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. (2016). Seven years of IASI ozone retrievals from FORLI: validation with independent total column and vertical profile measurements (Vol. 9).
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