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

I. Hessler (1, 2) , S. P. Harrison (2) , Michal Kucera (1) , C. Waelbroeck (3, 4) , Min-Te Chen (5) , C. Anderson (6) , Anne de Vernal (7) , B. Fréchette (7) , A. Cloke-Hayes (8) , Guillaume Leduc (9) , L. Londeix (10)

1 MARUM - Center for Marine Environmental Sciences [Bremen]
2 Department of Biological Sciences and Climate Futures - Macquarie University
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 PALEOCEAN - Paléocéanographie
5 Institute of applied Geosciences
6 Uni Research Climate
7 GEOTOP - Centre de recherche en géochimie et géodynamique
8 CAU - Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel
9 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
10 EPOC - Environnements et Paléoenvironnements OCéaniques

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 bench-marking 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.

Mots clés: sae surface; mid-Holocene (MH); Temperature; palaeothermometry

Domaines: Océan, Atmosphère; Interfaces continentales, environnement

I. Hessler, S. P. Harrison, Michal Kucera, C. Waelbroeck, Min-Te Chen, et al.. Implication of methodological uncertainties for mid-Holocene sea surface temperature reconstructions. Climate of the Past, 2014, 10 (6), pp.2237 - 2252. ⟨10.5194/cp-10-2237-2014⟩. ⟨hal-01472098⟩