Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 4.252 IF 4.252
  • IF 5-year value: 4.890 IF 5-year 4.890
  • CiteScore value: 4.49 CiteScore 4.49
  • SNIP value: 1.539 SNIP 1.539
  • SJR value: 2.404 SJR 2.404
  • IPP value: 4.28 IPP 4.28
  • h5-index value: 40 h5-index 40
  • Scimago H index value: 51 Scimago H index 51
Discussion papers
https://doi.org/10.5194/gmd-2018-283
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gmd-2018-283
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Model evaluation paper 05 Dec 2018

Model evaluation paper | 05 Dec 2018

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Geoscientific Model Development (GMD).

Paleo calendar-effect adjustments in time-slice and transient climate-model simulations (PaleoCalAdjust v1.0): impact and strategies for data analysis

Patrick J. Bartlein1 and Sarah L. Shafer2 Patrick J. Bartlein and Sarah L. Shafer
  • 1Department of Geography, University of Oregon, Eugene, OR 97403, USA
  • 2Geosciences and Environmental Change Science Center, U.S. Geological Survey, Corvallis, OR 97331 , USA

Abstract. The “paleo calendar effect” is a common expression for the impact that the changes in the length of months or seasons over time, related to changes in the eccentricity of Earth's orbit and precession, have on the analysis or summarization of climate-model output. This effect can have significant implications for paleoclimate analyses. In particular, using a “fixed-length” definition of months (i.e. defined by a fixed number of days), as opposed to a “fixed-angular” definition (i.e. defined by a fixed number of degrees of the Earth's orbit), leads to comparisons of data from different positions along the Earth's orbit when comparing paleo with modern simulations. This effect can impart characteristic spatial patterns or signals in comparisons of time-slice simulations that otherwise might be interpreted in terms of specific paleoclimatic mechanisms, and we provide examples for 6, 97, 116, and 127ka. The calendar effect is exacerbated in transient climate simulations, where, in addition to spatial or map-pattern effects, it can influence the apparent timing of extrema in individual time series and the characterization of phase relationships among series. We outline an approach for adjusting paleo simulations that have been summarized using a modern fixed-length definition of months and that can also be used for summarizing and comparing data archived as daily data. We describe the implementation of this approach in a set of Fortran 90 programs and modules (PaleoCalAdjust v1.0).

Patrick J. Bartlein and Sarah L. Shafer
Interactive discussion
Status: open (until 30 Jan 2019)
Status: open (until 30 Jan 2019)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Patrick J. Bartlein and Sarah L. Shafer
Model code and software

PaleoCalAdjust v1.0 P. J. Bartlein and S. L. Shafer https://doi.org/10.5281/zenodo.1478824

Patrick J. Bartlein and Sarah L. Shafer
Viewed  
Total article views: 139 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
105 33 1 139 0 3
  • HTML: 105
  • PDF: 33
  • XML: 1
  • Total: 139
  • BibTeX: 0
  • EndNote: 3
Views and downloads (calculated since 05 Dec 2018)
Cumulative views and downloads (calculated since 05 Dec 2018)
Viewed (geographical distribution)  
Total article views: 129 (including HTML, PDF, and XML) Thereof 129 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 10 Dec 2018
Publications Copernicus
Special issue
Download
Short summary
One of the consequences of the changes in the shape of Earth's orbit over time (in addition to pacing glacial/interglacial variations) is changes in the length of months or seasons. The well-known “paleo calendar effect” that results can produce patterns in comparisons of present-day and paleo climate-model simulations that could be mistaken for real climate changes. We illustrate the source of those patterns and describe an approach and set of programs for routinely adjusting for the effect.
One of the consequences of the changes in the shape of Earth's orbit over time (in addition to...
Citation
Share