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Evaluating model outputs using integrated global speleothem records of climate change since the last glacial

Comas-Bru, L; Harrison, SP; Werner, M; Rehfeld, K; Scroxton, N; Veiga-Pires, C; Ahmad, SM; ... Zhang, H; + view all (2019) Evaluating model outputs using integrated global speleothem records of climate change since the last glacial. Climate of the Past , 15 (4) pp. 1557-1579. 10.5194/cp-15-1557-2019. Green open access

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Abstract

Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data–model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data–model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices.

Type: Article
Title: Evaluating model outputs using integrated global speleothem records of climate change since the last glacial
Open access status: An open access version is available from UCL Discovery
DOI: 10.5194/cp-15-1557-2019
Publisher version: https://doi.org/10.5194/cp-15-1557-2019
Language: English
Additional information: This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Keywords: Science & Technology, Physical Sciences, Geosciences, Multidisciplinary, Meteorology & Atmospheric Sciences, Geology, STABLE-ISOTOPE VARIATIONS, GROWTH FREQUENCY VARIATIONS, GENERAL-CIRCULATION MODEL, DELTA-O-18 WATER ISOTOPE, HIGH-RESOLUTION, OXYGEN-ISOTOPE, ASIAN MONSOON, ATMOSPHERIC CIRCULATION, NORTH-ATLANTIC, PMIP4 CONTRIBUTION
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
UCL > Provost and Vice Provost Offices > UCL SLASH
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography
URI: https://discovery.ucl.ac.uk/id/eprint/10086566
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