The Gulf Stream and Atlantic Sea-Surface Temperatures in AD1790-1825

• Main Authors: G. Van Der Schrier, S. L. Weber
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2006
• Subjects: Gulf Stream; Atlantic ocean; early SST data; Little Ice Age; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.516.28; http://www.knmi.nl/~schrier/IJCrennell2007.pdf

Gridded Sea-Surface Temperatures (SSTs) for the Atlantic basin (45S-60N), as averages over the period AD 1790-1825, are produced and anal-ysed. The early instrumental SST measurements on which this recon-struction is based, were compiled by Major James Rennell and made by numerous British naval vessels on behalf of the British Admiralty. The digitization of this dataset and the reconstruction of averaged conditions, for both the November-March and May-September periods, are described. Spatially coherent reconstructions are calculated using a reduced space Optimal Interpolation technique in which the data is projected on a lim-ited number of empirical orthogonal functions. This approach is validated on modern data which are sampled in a similar way as the early instru-mental data. The reconstruction for the November-March period shows a large area with anomalously high temperatures from the point where the Gulf Stream separates from the coast until ca. 15W. A tongue of anomalous cool water is found at the eastern side of the North Atlantic basin, along the coast of Europe and northern Africa. In the north eastern South Atlantic, anomalously high temperatures are found, while temper-atures in the south western South Atlantic are anomalously cool. For the March-September season, anomalous temperatures in the South Atlantic are similar, but stronger, compared to those in the boreal cold season. In the central North Atlantic, anomalously high temperatures are found.