Reference
Kuhnert, H. and Mulitza, S. 2011. Multidecadal variability and late medieval cooling of near-coastal sea surface temperatures in the eastern tropical North Atlantic. Paleoceanography 26: 10.1029/2011PA002130.
Description
Sea surface temperatures (SSTs) were derived from Mg/Ca ratios of Globigerinoides ruber foraminifers that were extracted from gravity core GeoB 9501-5 that was recovered off southern Mauritania at 16°50'N, 16°44'W from a water depth of 323 m during Meteor cruise M65/1 - described by Mulitza (2006) - using the calibration for the 250-350 µm fraction of G. ruber (pink) from Anand et al. (2003) to produce a 1700-year summer-fall SST history. Between AD 850 and AD 1150, Kuhnert and Mulitza identify a period of warmth that they equate with the Medieval Warm Period, the peak 50-year mean SST of which was 1.1°C greater than the corresponding 50-year mean SST at the end of the record, which had been trending upward over the prior half-century.