The correlation between the U37k index and sea surface temperatures in the warm boundary:: The South China Sea

The South China Sea, due to its location and high sedimentary C-37 alkenone concentrations, is an ideal environment for the evaluation of the linear relationship between the alkenone-derived U-37(k), index and sea surface temperatures (SST) at the warm boundary. The alkenone compounds in this system have been analyzed in a series of coretop sediments covering most of the areas situated far from the influence of riverine inputs. The resulting U-37(k) indices have been correlated with averaged SST of various depth levels and seasons. Curve fitting of these parameters have shown that the linear U-37(k)/SST relationship is maintained at the warm end, which strongly contrasts with the lack of correlation at low SST reported in other studies. The best curve fittings of the U-37(k) measurements are obtained for the annually averaged 0-30 m water column temperatures, providing a linear equation, U-37(k) = 0.031T + 0.092, that is the same within error limits as those previously obtained in open ocean sites or Emiliania huxleyi cultures. Copyright (C) 1997 Elsevier Science Ltd.