B
Bernard Pak
Researcher at Commonwealth Scientific and Industrial Research Organisation
Publications - 22
Citations - 4158
Bernard Pak is an academic researcher from Commonwealth Scientific and Industrial Research Organisation. The author has contributed to research in topics: Terrestrial ecosystem & Carbon cycle. The author has an hindex of 17, co-authored 22 publications receiving 3731 citations. Previous affiliations of Bernard Pak include CSIRO Marine and Atmospheric Research & University of Melbourne.
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Journal ArticleDOI
Towards robust regional estimates of CO2 sources and sinks using atmospheric transport models.
Kevin R. Gurney,Rachel M. Law,A. S. Denning,Peter Rayner,David Baker,Philippe Bousquet,Lori Bruhwiler,Yu-Hsin Chen,Philippe Ciais,Song-Miao Fan,Inez Fung,Manuel Gloor,Martin Heimann,Kaz Higuchi,Jasmin John,Takashi Maki,Shamil Maksyutov,Kenneth A. Masarie,Philippe Peylin,Michael J. Prather,Bernard Pak,James T. Randerson,Jorge L. Sarmiento,S. Taguchi,Taro Takahashi,C.-W. Yuen +25 more
TL;DR: An uptake of CO2 in the southern extratropical ocean less than that estimated from ocean measurements is found, a result that is not sensitive to transport models or methodological approaches, and carbon fluxes integrated over latitudinal zones are strongly constrained by observations in the middle to high latitudes.
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A global model of carbon, nitrogen and phosphorus cycles for the terrestrial biosphere
TL;DR: In this article, a global model of carbon (C), nitrogen (N) and phosphorus (P) cycles for the terrestrial biosphere was developed, which was used to derive the global distribution and uncertainty of N or P limitation on the productivity of terrestrial ecosystems at steady state under present conditions.
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TransCom 3 inversion intercomparison: Impact of transport model errors on the interannual variability of regional CO2 fluxes, 1988–2003
D. F. Baker,D. F. Baker,Rachel M. Law,Kevin R. Gurney,Kevin R. Gurney,Peter Rayner,P. Peylin,A. S. Denning,Philippe Bousquet,Lori Bruhwiler,Yu-Hsin Chen,Philippe Ciais,Inez Fung,Martin Heimann,Jasmin John,Takashi Maki,Shamil Maksyutov,Kenneth A. Masarie,Michael J. Prather,Bernard Pak,Bernard Pak,S. Taguchi,Z. Zhu +22 more
TL;DR: In this article, the same inversion (method, priors, data) is performed with 13 different atmospheric transport models, and the spread in the results is taken as a measure of transport model error.
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Transcom 3 inversion intercomparison: Model mean results for the estimation of seasonal carbon sources and sinks
Kevin R. Gurney,Rachel M. Law,A. Scott Denning,Peter Rayner,Bernard Pak,David Baker,Philippe Bousquet,L. Bruhwiler,Yu Han Chen,Philippe Ciais,Inez Fung,Martin Heimann,Jasmin John,Takashi Maki,Shamil Maksyutov,Philippe Peylin,Michael J. Prather,S. Taguchi +17 more
Abstract: [1] The TransCom 3 experiment was begun to explore the estimation of carbon sources and sinks via the inversion of simulated tracer transport. We build upon previous TransCom work by presenting the seasonal inverse results which provide estimates of carbon flux for 11 land and 11 ocean regions using 12 atmospheric transport models. The monthly fluxes represent the mean seasonal cycle for the 1992 to 1996 time period. The spread among the model results is larger than the average of their estimated flux uncertainty in the northern extratropics and vice versa in the tropical regions. In the northern land regions, the model spread is largest during the growing season. Compared to a seasonally balanced biosphere prior flux generated by the CASA model, we find significant changes to the carbon exchange in the European region with greater growing season net uptake which persists into the fall months. Both Boreal North America and Boreal Asia show lessened net uptake at the onset of the growing season with Boreal Asia also exhibiting greater peak growing season net uptake. Temperate Asia shows a dramatic springward shift in the peak timing of growing season net uptake relative to the neutral CASA flux while Temperate North America exhibits a broad flattening of the seasonal cycle. In most of the ocean regions, the inverse fluxes exhibit much greater seasonality than that implied by the DpCO2 derived fluxes though this may be due, in part, to misallocation of adjacent land flux. In the Southern Ocean, the austral spring and fall exhibits much less carbon uptake than implied by DpCO2 derived fluxes. Sensitivity testing indicates that the inverse estimates are not overly influenced by the prior flux choices. Considerable agreement exists between the model mean, annual mean results of this study and that of the previously published TransCom annual mean inversion. The differences that do exist are in poorly constrained regions and tend to exhibit compensatory fluxes in order to match the global mass constraint. The differences between the estimated fluxes and the prior model over the northern land regions could be due to the prior model respiration response to temperature. Significant phase differences, such as that in the Temperate Asia region, may be due to the limited observations for that region. Finally, differences in the boreal land regions between the prior model and the estimated fluxes may be a reflection of the timing of spring thaw and an imbalance in respiration versus photosynthesis. INDEX TERMS: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 1615 Global Change: Biogeochemical processes (4805); 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; KEYWORDS: carbon transport, inversion
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Interannual growth rate variations of atmospheric CO2 and its δ13C, H2, CH4, and CO between 1992 and 1999 linked to biomass burning
R. L. Langenfelds,R. L. Langenfelds,Roger J. Francey,Bernard Pak,Bernard Pak,L. P. Steele,Jon Lloyd,Cathy M. Trudinger,C. E. Allison +8 more
TL;DR: In this paper, a major fraction of the variability is consistent with two emission pulses coinciding with large biomass burning events in tropical and boreal regions, and observations of unusually high levels of combustion products in the overlying troposphere at these times.