Abrupt Decrease in Tropical Pacific Sea Surface Salinity at End of Little Ice Age
Erica J. Hendy,1*
Michael K. Gagan,1
Chantal A. Alibert,1
Malcolm T. McCulloch,1
Janice M. Lough,2
Peter J. Isdale2
A 420-year history of strontium/calcium,
uranium/calcium, and oxygen isotope ratios in eight coral cores from
the Great Barrier Reef, Australia, indicates that sea surface
temperature and salinity were higher in the 18th century than in the
20th century. An abrupt freshening after 1870 occurred simultaneously
throughout the southwestern Pacific, coinciding with cooling tropical
temperatures. Higher salinities between 1565 and 1870 are best
explained by a combination of advection and wind-induced evaporation
resulting from a strong latitudinal temperature gradient and
intensified circulation. The global Little Ice Age glacial expansion
may have been driven, in part, by greater poleward transport of water
vapor from the tropical Pacific.
1 Research School of Earth Sciences, Australian
National University, Canberra, ACT 0200, Australia.
2 Australian Institute of Marine Science, PMB 3, Townsville M.C., Queensland 4810, Australia.
*
To whom correspondence should be addressed. E-mail:
erica.hendy{at}anu.edu.au
