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Climate of the Past An interactive open-access journal of the European Geosciences Union
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
24 Jun 2011
Review status
This discussion paper is a preprint. A revision of the manuscript for further review has not been submitted.
Degree-day melt models for paleoclimate reconstruction from tropical glaciers: calibration from mass balance and meteorological data of the Zongo glacier (Bolivia, 16° S)
P.-H. Blard1, P. Wagnon3,2, J. Lavé1, A. Soruco4, J.-E. Sicart3,2, and B. Francou3 1Centre de Recherches Pétrographiques et Géochimiques, CNRS UPR2300, Université de Lorraine, 15 rue Notre Dame des Pauvres, BP20, 54501 Vandoeuvre-lès-Nancy, Cedex, France
2Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS UMR5183, Université Joseph Fourier,-Grenoble 1, CNRS, IRD, G-INP, 38402, Grenoble, France
3Laboratoire d'étude des Transferts en Hydrologie et Environnement, UMR5564, Université Joseph Fourier,-Grenoble 1, CNRS, G-INP, IRD, 38402, Grenoble, France
4Instituto de Investigaciones Geológicas y del Medio Ambiente (IGEMA), Universidad Mayor de San Andrés (UMSA), Calle 27, Pabellón 3, Campus Universitario Cota Cota, Casilla 35140, La Paz, Bolivia
Abstract. This paper describes several simple positive degree-day models (hereafter referred as "PDD models") designed to provide past climatic reconstruction from tropical glacier paleo-equilibrium altitude lines (paleo-ELA). Several ablation laws were tested and calibrated using the monthly ablation and meteorological data recorded from 1997 to 2006 on the Zongo glacier (Cordillera Real, Bolivia, 16° S). The performed inversion analyses indicate that the model provides a better reconstruction of the mass balance if the ablation is modeled with different melting factors for snow and ice. The inclusion of short-wave solar radiations does not induce a substantial improvement. However, this type of model may be very useful to quantify the effects of local topographic (orientation, shading) and to take into account incoming solar radiation changes at geological timescale. The performed sensitivity test indicates that, in spite of the uncertainty in the calibrated snow-ice ablation factors, all models are able to provide paleotemperatures with ~1 °C uncertainty for a given paleoprecipitation. This error includes a 50 m uncertainty in the estimate of the paleoELA. Finally, the models are characterized by different precipitation-temperature sensitivities: if a similar warming is applied, model including different ablation factors for snow and ice requires a lower precipitation increase (by ∼15 %) than others to maintain the ELA.
Citation: Blard, P.-H., Wagnon, P., Lavé, J., Soruco, A., Sicart, J.-E., and Francou, B.: Degree-day melt models for paleoclimate reconstruction from tropical glaciers: calibration from mass balance and meteorological data of the Zongo glacier (Bolivia, 16° S), Clim. Past Discuss., 7, 2119-2158,, 2011.
P.-H. Blard et al.
Interactive discussionStatus: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version      Supplement - Supplement
RC C1170: 'Review', Anonymous Referee #1, 04 Aug 2011 Printer-friendly Version Supplement 
RC C1307: 'Review', Anonymous Referee #2, 23 Aug 2011 Printer-friendly Version Supplement 
EC C1678: 'Editor's comment', Volker Rath, 24 Oct 2011 Printer-friendly Version 
AC C1982: 'Responses to Reviewer 1 and reviewer 2', Pierre-Henri Blard, 07 Dec 2011 Printer-friendly Version Supplement 
P.-H. Blard et al.
P.-H. Blard et al.


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