Articles | Volume 10, issue 6
Clim. Past, 10, 2237–2252, 2014
Clim. Past, 10, 2237–2252, 2014

Research article 17 Dec 2014

Research article | 17 Dec 2014

Implication of methodological uncertainties for mid-Holocene sea surface temperature reconstructions

I. Hessler1,2, S. P. Harrison1,3, M. Kucera2, C. Waelbroeck4, M.-T. Chen5, C. Anderson6, A. de Vernal7, B. Fréchette7, A. Cloke-Hayes8, G. Leduc9,10, and L. Londeix11 I. Hessler et al.
  • 1Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
  • 2MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
  • 3Centre for Past Climate Change and School of Archaeology, Geography and Environmental Sciences (SAGES), University of Reading, Whiteknights, Reading, UK
  • 4Laboratoire des Sciences du Climat et de l'Environnement LSCE/IPSL, Laboratoire CNRS-CEA- UVSQ, Gif-sur-Yvette, France
  • 5Institute of Applied Geosciences, National Taiwan Ocean University, Keelung, Taiwan
  • 6Uni Climate, Uni Research and the Bjerknes Centre for Climate Research, Bergen, Norway
  • 7GEOTOP, Université du Québec à Montréal, Montréal, Canada
  • 8Mary Immaculate College, University of Limerick, Limerick, Ireland
  • 9Christian-Albrechts Universität zu Kiel, Marine Climate Research, Kiel, Germany
  • 10CEREGE, UMR7330, Aix-en-Provence, France
  • 11Université de Bordeaux, UMR `EPOC' CNRS, Talence, France

Abstract. We present and examine a multi-sensor global compilation of mid-Holocene (MH) sea surface temperatures (SST), based on Mg/Ca and alkenone palaeothermometry and reconstructions obtained using planktonic foraminifera and organic-walled dinoflagellate cyst census counts. We assess the uncertainties originating from using different methodologies and evaluate the potential of MH SST reconstructions as a benchmark for climate-model simulations. The comparison between different analytical approaches (time frame, baseline climate) shows the choice of time window for the MH has a negligible effect on the reconstructed SST pattern, but the choice of baseline climate affects both the magnitude and spatial pattern of the reconstructed SSTs. Comparison of the SST reconstructions made using different sensors shows significant discrepancies at a regional scale, with uncertainties often exceeding the reconstructed SST anomaly. Apparent patterns in SST may largely be a reflection of the use of different sensors in different regions. Overall, the uncertainties associated with the SST reconstructions are generally larger than the MH anomalies. Thus, the SST data currently available cannot serve as a target for benchmarking model simulations. Further evaluations of potential subsurface and/or seasonal artifacts that may contribute to obscure the MH SST reconstructions are urgently needed to provide reliable benchmarks for model evaluations.