Global and regional sea surface temperature trends during Marine Isotope Stage 11

Abstract

Abstract. The Marine Isotope Stage (MIS) 11 (424-374 ka) was characterized by a protracted deglaciation and an unusually long climatic optimum. It remains unclear to what degree the climate development during this interglacial reflects the unusually weak orbital forcing or greenhouse gas trends. Previously, arguments about the duration and timing of the MIS11 climatic optimum and about the pace of the deglacial warming were based on a small number of key records, which appear to show regional differences. In order to obtain a global signal of climate evolution during MIS11, we compiled a database of 78 sea surface temperature (SST) records from 57 sites spanning MIS11, aligned these individually on the basis of benthic (N = 28) or planktonic (N = 31) stable oxygen isotope curves to a common time frame and subjected 48 of them to an empirical orthogonal function (EOF) analysis. The analysis revealed a high commonality among all records, with the principal SST trend explaining almost 49 % of the variability. This trend indicates that on the global scale, the surface ocean underwent rapid deglacial warming during Termination V, in pace with carbon dioxide rise, followed by a broad SST optimum centered at ∼ 410 kyr. The second EOF, which explained ∼18 % of the variability, revealed the existence of a different SST trend, characterized by a delayed onset of the temperature optimum during MIS11 at ∼ 398 kyr, followed by a prolonged warm period lasting beyond 380 kyr. This trend is most consistently manifested in the mid-latitude North Atlantic and Mediterranean Sea and is here attributed to the strength of the Atlantic meridional overturning circulation. A sensitivity analysis indicates that these results are robust to record selection and to age-model uncertainties of up to 3-6 kyr, but more sensitive to SST seasonal attribution and SST uncertainties > 1 • C. In order to validate the CCSM3 (Community Climate System Model, version 3) predictive potential, the annual and seasonal SST anomalies recorded in a total of 74 proxy records were compared with runs for three time slices representing orbital configuration extremes during the peak interglacial of MIS11. The modeled SST anomalies are characterized by a significantly lower variance compared to the reconstructions. Nevertheless, significant correlations between proxy and model data are found in comparisons on the seasonal basis, indicating that the model captures part of the long-term variability induced by astronomical forcing, which appears to have left a detectable signature in SST trends.

Interglacials of the last 800,000 years

“…Note that changes in CH 4 concentration also reflect the impacts of NH climate on methane emissions. Antarctic temperatures inferred from the EDC δD signal [ Jouzel et al , ] have been related to global‐scale temperature changes with a polar amplification factor of ~2 at glacial‐interglacial scale [ Masson‐Delmotte et al , ], consistent with recent findings [ Elderfield et al , ; Milker et al , ].…”

“…Therefore, the main changes are in astronomical parameters (which can be calculated precisely) and GHG concentrations (which are derived from ice core data); these can be modified as appropriate for the time period under study. A very few studies have carried out snapshots for earlier interglacials [ Yin and Berger , ; Herold et al , ; Yin and Berger , ; Milker et al , ; Muri et al , ; Yin and Berger , ]. The evaluation of snapshot simulations is severely hampered by the scarcity of data compilations for previous interglacials.…”

“…As an example, the PMIP3 LIG intercomparison was evaluated against a compilation that consisted of a single value of temperature for each site [ Turney and Jones , ] for the whole interglacial, which clearly makes the separate evaluation of snapshots at 125 and 130 ka impossible. Work is underway to improve this situation for a number of interglacials, including MIS 5e [ Capron et al , ] and MIS 11 [ Milker et al , ; Kleinen et al , ].…”

Bering Sea surface water conditions during Marine Isotope Stages 12 to 10 at Navarin Canyon (IODP Site U1345)

“…Despite the work done to characterize the warmth of MIS 11 in the terrestrial realm (Candy et al, 2014;Melles et al, 2012;Prokopenko et al, 2010), as well as the North Atlantic (Bauch et al, 2000;Chaisson et al, 2002;Dickson et al, 2009;Milker et al, 2013;Poli et al, 2010), little is known about this interval from the North Pacific and Bering Sea region (Candy et al, 2014). Modeling studies describe several mechanisms for linking the Atlantic and Pacific through oceanic heat transport on glacial-interglacial timescales (De- Figure 1.…”

Transient simulations of the present and the last interglacial climate using the Community Climate System Model version 3: effects of orbital acceleration

“…In equilibrium simulations, the boundary conditions are not varied temporally but rather kept fixed under the assumption that the Earth system is in equilibrium with them (e.g. Braconnot et al, 2007;Lunt et al, 2013;Milker et al, 2013;Rachmayani et al, 2016). Evidently, only limited information regarding the temporal evolution of the dynamic system is obtained by the time slice approach.…”