Incorporating NGRIP with calibrated data in new interface

[Ken Lawrence]

Hello everyone,

Is there a way to incorporate NGRIP data with your calibrated results with the new OxCal interface?  There used to be a way to do it, but I haven't figured it out with the new system.

Thanks in advance for your assistance,

Ken

[Christopher Ramsey]

Ken

No this is on the to-do list. The old method did not take account of what we know about the differences between the NGRIP and IntCal timescales so I was wanting to do this properly.

At the moment you can still use the old interface at:

https://c14.arch.ox.ac.uk/oxcalold/OxCal.html

if you need that feature.

Best wishes

Christopher

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[Christopher Ramsey]

Dear all

It is now possible to include the NGRIP data into plots on the new interface.  This makes use of the 10Be/14C synchronisation between IntCal20 and GICC05.  This is done by interchanging information and plots between OxCal and the IntChron integration tool.  To do this you need to use the [Format > Plot data] option in multiples, age-depths plots or curve based plots.  Here is a full set of instructions:

1. Clear your cache to make sure you are using the latest version of all the files
2. Call up any multi-plot/age depth plot etc
3. Use the [Edit > Format] menu
4. Select under the options "Plot data"

This will open a new (IntChron) window with a plot of the NGRIP data on the same scale as your original plot.  This has used the NGRIP data, GICC05 timescale and time-transfer function to provide NGRIP on the IntCal20 or absolute timescale.

5. Return to the OxCal window
6. Press [Ok] to confirm the format change

You should now have the NGRIP data on top of your ordinary plot - with a 1 sigma uncertainty envelope for the known age uncertainty.

Any changes you make to the plot (span, start etc should be reflected in the plot at the top).

If you return to the IntChron and press [Cite] on the plot you will see a list of the publications behind the data.  In the "Bibliography" window you can press [Display] to see a display version of the publications (and direct links).  If you press the [Import/Export] button you should get those publications in BibTeX format for importing into citation tools.

For reference the full set of publications related to the data plotted are:

• Adolphi, F. and Muscheler, R. (2016) Synchronizing the Greenland ice core and radiocarbon timescales over the Holocene--Bayesian wiggle-matching of cosmogenic radionuclide records. Climate of the Past, 12(1). doi:10.5194/cp-12-15-2016
• Adolphi, F., Bronk Ramsey, C., Erhardt, T., Lawrence Edwards, R., Cheng, H., Turney, C.S.M., Cooper, A., Svensson, A., Rasmussen, S.O., Fischer, H. and Muscheler, R. (2018) Connecting the Greenland ice-core and U/Th timescales via cosmogenic radionuclides: Testing the synchronicity of Dansgaard-Oeschger events. Climate of the Past, 14. doi:10.5194/cp-14-1755-2018
• Andersen, K.K., Azuma, N., Barnola, J., Bigler, M., Biscaye, P., Caillon, N., Chappellaz, J., Clausen, H.B., Dahl-Jensen, D., Fischer, H. and others (2004) High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature, 431(7005). doi:10.1038/nature02805
• Andersen, K.K., Svensson, A., Johnsen, S.J., Rasmussen, S.O., Bigler, M., Röthlisberger, R., Ruth, U., Siggaard-Andersen, M.L., Peder Steffensen, J., Dahl-Jensen, D. and others (2006) The Greenland ice core chronology 2005, 15--42ka. Part 1: Constructing the time scale. Quaternary Science Reviews, 25(23). doi:10.1016/j.quascirev.2006.08.002
• Rasmussen, S.O., Andersen, K.K., Svensson, A.M., Steffensen, J.P., Vinther, B.M., Clausen, H.B., Siggaard-Andersen, M.-., Johnsen, S.J., Larsen, L.B., Dahl-Jensen, D., Bigler, M., Röthlisberger, R., Fischer, H., Goto-Azuma, K., Hansson, M.E. and Ruth, U. (2006) A new Greenland ice core chronology for the last glacial termination. Journal of Geophysical Research, 111(D6). doi:10.1029/2005jd006079
• Rasmussen, S.O., Seierstad, I.K., Andersen, K.K., Bigler, M., Dahl-Jensen, D. and Johnsen, S.J. (2008) Synchronization of the NGRIP, GRIP, and GISP2 ice cores across MIS 2 and palaeoclimatic implications. Quaternary Science Reviews, 27(1-2). doi:10.1016/j.quascirev.2007.01.016
• Svensson, A., Andersen, K.K., Bigler, M., Clausen, H.B., Dahl-Jensen, D., Davies, S.M., Johnsen, S.J., Muscheler, R., Rasmussen, S.O., Röthlisberger, R., Steffensen, J.P. and Vinther, B.M. (2006) The Greenland Ice Core Chronology 2005, 15-42 ka. Part 2: comparison to other records. Quaternary Science Reviews, 25(23-24). doi:10.1016/j.quascirev.2006.08.003
• Svensson, A., Andersen, K.K., Bigler, M., Clausen, H.B., Dahl-Jensen, D., Davies, S., Johnsen, S.J., Muscheler, R., Parrenin, F., Rasmussen, S.O. and others (2008) A 60 000 year Greenland stratigraphic ice core chronology. Climate of the Past, 4(1). doi:10.5194/cp-4-47-2008

You might also include:

• Bronk Ramsey, C., Albert, P., Blockley, S., Hardiman, M., Lane, C., Macleod, A., Matthews, I.P., Muscheler, R., Palmer, A. and Staff, R.A. (2014) Integrating timescales with time-transfer functions: a practical approach for an INTIMATE database. Quaternary Science Reviews, 106, pp.67-80. doi:10.1016/j.quascirev.2014.05.028

which explains the methodology behind the plot.

In principle this approach can be used to include any data plotted as a single proxy plot in the IntChron integration tool.  This tool will be included in the next downloadable version of OxCal and is also the framework used for the IntCal database.

Best wishes

Christopher