Sea surface temperature anomalies in the oceans at the LGM estimated from the alkenone‐U37K′ index: comparison with GCMs

[1] U K' 37 sea surface temperature (SST) estimates for the Last Glacial Maximum (LGM) are discussed and compared to coupled general circulation model (GCM) results. We conclude that U K' 37 estimates and most numerical models agree in the magnitude of the large scale SST cooling features of the glacial ocean. There was a larger cooling in the northern than in the Southern Hemisphere. The eastern boundary currents and equatorial regions were also colder. There is a consensus between models and alkenone data for a tropical cooling of about -2°C, which is in disagreement with both a smaller cooling as suggested by the CLIMAP project reconstruction, or a more pronounced cooling as suggested from coral proxy records. The comprehensive HadCM3 simulation examined reproduces a puzzling feature of the U K' 37-SST reconstruction, i.e., the warming of the glacial north Atlantic, which needs further investigation using numerical modelling and proxy data reconstruction.