Sea surface temperature record off central Japan since the Last Glacial Maximum using planktonic foraminiferal Mg/Ca thermometry

2005 ◽  
Vol 21 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Takuya Sagawa ◽  
Kazuhiro Toyoda ◽  
Tadamichi Oba
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Last Glacial Maximum ◽  
Sea Surface ◽  
Temperature Record ◽  
Central Japan ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
Surface Temperature Record ◽  
The Last Glacial

Reconstruction of sea-surface temperature, salinity, and sea-ice cover in the northern North Atlantic during the last glacial maximum based on dinocyst assemblages

2000 ◽  
Vol 37 (5) ◽  
pp. 725-750 ◽  
Author(s):  
Anne de Vernal ◽  
Claude Hillaire-Marcel ◽  
Jean-Louis Turon ◽  
Jens Matthiessen
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Last Glacial Maximum ◽  
North Atlantic ◽  
Ice Cover ◽  
Glacial Maximum ◽  
Sea Surface ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Past sea-surface conditions over the northern North Atlantic during the last glacial maximum were examined from the study of 61 deep-sea cores. The last glacial maximum time slice studied here corresponds to an interval between Heinrich layers H2 and H1, and spanning about 20-16 ka on a 14C time scale. Transfer functions based on dinocyst assemblages were used to reconstruct sea-surface temperature, salinity, and sea-ice cover. The results illustrate extensive sea-ice cover along the eastern Canadian margins and sea-ice spreading, only during winter, over most of the northern North Atlantic. On the whole, much colder winter prevailed, despite relatively mild conditions in August (10-15°C at most offshore sites), thus suggesting a larger seasonal contrast of temperatures than today. Lower salinity than at present is reconstructed, especially along the eastern Canadian and Scandinavian margins, likely because of meltwater supply from the surrounding ice sheets. These reconstructions contrast with those established by CLIMAP on the basis of planktonic foraminifera. These differences are discussed with reference to the stratigraphical frame of the last glacial maximum, which was not the coldest phase of the last glacial stage. The respective significance of dinocyst and foraminifer records is also examined in terms of the thermohaline characteristics of surface waters and the vertical structure of upper water masses, which was apparently much more stratified than at present in the northern North Atlantic, thus preventing deep-water formation.

A Statistical Reconstruction of Sea-Surface Temperature and Sea-Ice Concentration for the Last Glacial Maximum

2021 ◽  
Author(s):  
Lachlan Astfalck ◽  
Daniel Williamson ◽  
Niall Gandy ◽  
Lauren Gregoire ◽  
Ruza Ivanovic
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Last Glacial Maximum ◽  
Sea Surface ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
Spatio Temporal ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Recent geoscience and palaeoclimatic modelling advances in have seen an increasing demand for spatio-temporal reconstructions of climatic variables. Satisfactory reconstructions should consider all sources of information: both numerical model ensembles and measured data. The difficulty in modelling climatic variables often gives rise to a multiplicity of models due to large uncertainty in the inputs. Climate proxy-based measurements are similarly uncertain due to both measurement noise and reconstruction error. It is thus vital to provide a reconstruction methodology in which these uncertainties are appropriately quantified. Instead of utilising probability based approaches that can be very computationally demanding for geospatio-temporal problems, we have developed a new approach to do this utilising a second-order framework; namely, Bayes linear analysis. This framework avoids the explicit specification of probability distributions and allows reconstructions to be described simply by means and variances. Methodological advances are made to the traditional Bayes linear mechanics to allow for non-linearity. To demonstrate the methodology, average monthly spatial reconstructions of sea-surface temperature and sea-ice concentration are estimated for the Last Glacial Maximum (21 ka), combining PMIP3 and PMIP4 outputs and available palaeodata syntheses. The methodology presented is generalisable to many spatio-temporal quantities and is highly germane to the geoscience community. </p>

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