Journal cover Journal topic
Earth System Science Data The Data Publishing Journal
doi:10.5194/essd-2017-6
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
 
20 Feb 2017
Review status
This discussion paper is under review for the journal Earth System Science Data (ESSD).
Continuous records of the atmospheric greenhouse gases CO2, CH4, and N2O and their radiative forcing since the penultimate glacial maximum
Peter Köhler1, Christoph Nehrbass-Ahles2, Jochen Schmitt2, Thomas F. Stocker2, and Hubertus Fischer2 1Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung (AWI), P.O. Box 12 01 61, 27515 Bremerhaven, Germany
2Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
Abstract. Continuous records of the atmospheric greenhouse gases (GHGs) CO2, CH4, and N2O are necessary input data for transient climate simulations and their related radiative forcing important components in analyses of climate sensitivity and feedbacks. Since the available data from ice cores are discontinuous and partly ambiguous a well-documented decision process during data compilation followed by some interpolating post-processing are necessary to obtain those desired time series. Here we document our best-guess data compilation of published ice core records and recent measurements on firn air and atmospheric samples covering the time window from the penultimate glacial maximum (∼ 156 kyr BP) to the beginning of year 2016 CE. A smoothing spline method is applied to translate the discrete and irregularly spaced data points into continuous time series. These splines are assumed to represent the evolution of the atmospheric mixing ratios for the three GHGs. Global- mean radiative forcing for each GHG is computed using well-established, simple formulations. Newest published age scales are used for the ice core data. While CO2 is representing an integrated global signal, we compile only a southern hemisphere record of CH4 and identify how much larger a northern hemisphere or global CH4 record might have been due to its interhemispheric gradient. Data resolution and uncertainties are considered in the spline procedure and typical cutoff periods, defining the degree of smoothing, range from 5000 years for the less resolved older parts of the records to 4 years for the densely-sampled recent years. The data sets describe seamlessly the GHG evolution on orbital and millennial time scales for glacial and glacial-interglacial variations and on centennial and decadal time scales for anthropogenic times. Data connected with this paper, including raw data and final splines, are available at https://doi.pangaea.de/10.1594/PANGAEA.871273.

Citation: Köhler, P., Nehrbass-Ahles, C., Schmitt, J., Stocker, T. F., and Fischer, H.: Continuous records of the atmospheric greenhouse gases CO2, CH4, and N2O and their radiative forcing since the penultimate glacial maximum, Earth Syst. Sci. Data Discuss., doi:10.5194/essd-2017-6, in review, 2017.
Peter Köhler et al.
Peter Köhler et al.
Peter Köhler et al.

Viewed

Total article views: 385 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
299 78 8 385 5 10

Views and downloads (calculated since 20 Feb 2017)

Cumulative views and downloads (calculated since 20 Feb 2017)

Viewed (geographical distribution)

Total article views: 385 (including HTML, PDF, and XML)

Thereof 378 with geography defined and 7 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 28 May 2017
Download
Short summary
We document our best-guess data compilation of published ice core records of the greenhouse gases CO2, CH4 and N2O and recent measurements on firn air and atmospheric samples covering the time window from ∼156,000 years BP to the beginning of year 2016 CE. A smoothing spline method is applied to translate the discrete and irregularly spaced data points into continuous time series. Global-mean radiative forcing for each greenhouse gas is computed using well-established, simple formulations.
We document our best-guess data compilation of published ice core records of the greenhouse...
Share