Orbital and suborbital climate variability in the Sulu Sea, western tropical Pacific

Type Article
Date 2003-01
Language English
Author(s) Oppo Dw1, Linsley Bk2, Rosenthal Y3, Dannenmann S4, Beaufort L5
Affiliation(s) 1 : Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA.
2 : SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12222 USA.
3 : Rutgers State Univ, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA.
4 : Rutgers State Univ, Dept Geol, New Brunswick, NJ 08901 USA.
5 : CNRS, CEREGE, Aix En Provence, France.
Source Geochemistry Geophysics Geosystems (1525-2027) (Amer Geophysical Union), 2003-01 , Vol. 4 , N. 1 , P. 1-20
DOI 10.1029/2001GC000260
WOS© Times Cited 54
Keyword(s) Sulu Sea, tropical hydrography, East Asian monsoon, IMAGES, suborbital climate variability, sea level, paleoceanography, marginal and semienclosed seas, climate dynamics
Abstract A detailed record of planktic delta(18)O from a sediment core in the Sulu Sea, located between the South China Sea and the western Pacific warm pool, reveals that for the past 400 kyr (1 kyr = 1000 years), delta(18)O variability on orbital timescales is similar to that caused by changes in ice volume alone. This result indicates that in the Sulu Sea, temperature-driven changes in planktic delta(18)O on orbital times scales were generally compensated for by the effects of sea level and changes in seasonal monsoon intensity on the local freshwater budget, as well as by other changes in the tropical hydrologic cycle and their attendant effects on surface water delta(18)O. Increased freshening of the western tropical Pacific warm pool is reminiscent of La Nina conditions. However, we argue that the mean tropical climate state was not more La Nina-like than today on broader spatial scales. Suborbital variability occurred in the Sulu Sea throughout the past 400 kyr, suggesting little sensitivity to ice volume or to glacial-interglacial changes in tropical hydrology. Variations on 4-10 kyr timescales appear to be linked to those in the North Atlantic region, suggesting a common forcing of that variability. We suggest that Sulu Sea salinity variations were a response to suborbital climate variability in the North Atlantic region, transmitted via changes in the intensity of the East Asian summer monsoon. We suggest that a North Atlantic origin of that tropical suborbital variability can be reconciled with weak glacial amplification in the tropics if the tropical response is nonlinear.
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