Physics
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufmpp24a..02k&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #PP24A-02
Physics
1616 Climate Variability (1635, 3305, 3309, 4215, 4513), 1854 Precipitation (3354), 4900 Paleoceanography (0473, 3344), 4954 Sea Surface Temperature, 9320 Asia
Scientific paper
Variability and extremity of the East Asian summer monsoon (EASM) is of prime importance because one third of the world population lives in the area strongly influenced by EASM. Previous studies in China demonstrated that the timing of the precipitation maximum is different from place to place through the Holocene. However, most of the studies about EASM intensity focused on the terrestrial record, and EASM intensity has never been reconstructed continuously with high-resolution from marine record. The modern sea-surface salinity (SSS) in the northern part of the East China Sea (ECS) reflects the volume of the Changjiang (Yangtze River) discharge. Because the drainage area of the Changjiang occupies a major part of South China where EASM has a storong influence, the discharge of the Changjiang during summer is considered as a good indicator of EASM intensity. Piston core KY0704 PC-1 (128°56E, 31°38N), which we used in this study, was retrieved from the northern part of the ECS at a water depth of 758m. In order to reconstruct paleo-SST and paleo-SSS, the planktic foraminifera Globigerinoides ruber was used for analyses of oxygen isotope (δ18Oruber) and Mg/Ca. We estimated the oxygen isotope ratio of the ambient past seawater (δ18Osw) from δ18Oruber and Mg/Ca- derived SST. The result suggested that SST in the studied location increased by 3-4°C while δ18Osw decreased by approximately 1.2 permil from the last glacial to the Holocene. Millennial-scale variations between relatively warm and saline water and relatively cold and less saline water were recognized, suggesting the changes in the mixing ratio between the Changjiang Diluted water and the Kuroshio water during the Holocene. In order to remove the influence of the Kuroshio water, we subtracted δ18Osw of the central Okinawa Trough studied by Sun et al.(2005) from δ18Osw of our site. The difference of δ18Osw (δ18Odif) can be regarded as reflecting changes due to the influence of dilution of Changjiang discharge. Comparison of δ18Odif with the Holocene lake level record by An et al.(2000) revealed that δ18Odif changes showed a trend similar to the lake level changes in the middle and lower reaches of the Changjiang. This suggested that the δ18Osw record in the northern ECS reflects precipitation changes in the drainage basin of the middle and lower reaches of the Changjiang river. Therefore changes in the EASM intensity are recorded with high-resolution in marine cores from the northern ECS.
Kimoto Kazufumi
Kubota Yasuhiro
Oda Hiroshi
Tada Ryuji
Yokoyama Yfji
No associations
LandOfFree
Variations of East Asian Summer Monsoon Deduced from the Results of Mg/Ca and Oxygen Isotope of Planktic Foraminifera in the East China Sea Since the Last Deglaciation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Variations of East Asian Summer Monsoon Deduced from the Results of Mg/Ca and Oxygen Isotope of Planktic Foraminifera in the East China Sea Since the Last Deglaciation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variations of East Asian Summer Monsoon Deduced from the Results of Mg/Ca and Oxygen Isotope of Planktic Foraminifera in the East China Sea Since the Last Deglaciation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1243301