TY - JOUR
T1 - Sea surface temperature changes in the Okhotsk Sea and adjacent North Pacific during the last glacial maximum and deglaciation
AU - Harada, Naomi
AU - Sato, Miyako
AU - Seki, Osamu
AU - Timmermann, Axel
AU - Moossen, Heiko
AU - Bendle, James
AU - Nakamura, Yuriko
AU - Kimoto, Katsunori
AU - Okazaki, Yusuke
AU - Nagashima, Kana
AU - Gorbarenko, Sergey A.
AU - Ijiri, Akira
AU - Nakatsuka, Takeshi
AU - Menviel, Laurie
AU - Chikamoto, Megumi O.
AU - Abe-Ouchi, Ayako
AU - Schouten, Stefan
N1 - Funding Information:
We are grateful to Captain Akamine and the crew of R/V Mirai for their help with sediment collection in the Okhotsk Sea during the MR06-04 cruise. We also thank the crew of R/V Professor Khromov , operated by the Far Eastern Regional Hydrometeorological Research Institute, Russia, for their help with sediment collection in the Okhotsk Sea. This work was supported by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and the Research Joint Project between Japan and Pacific Oceanological Institute, Russia , and by Grant no. 06037711-000164 from the Japan Society for the Promotion of Science . SS acknowledges support from the Netherlands Organization for Scientific research through a VICI grant. This work was initiated as a collaborative research program between JAMSTEC (Japan) and another collaborative effort – Paleoclimate Dynamics – between JAMSTEC and the IPRC at the University of Hawai'i (USA), and then expanded to include the co-authors and their respective organizations.
PY - 2012/2
Y1 - 2012/2
N2 - We estimated sea surface temperatures (SSTs) in the western Okhotsk Sea during the last glacial maximum (LGM) and the last glacial termination from measurements of the alkenone unsaturation index (U K' 37), the Tetra Ether indeX of tetraethers consisting of 86 carbon atoms (TEX 86), and TEX 86 L in piston core sediments, which reveal the climate response of this region to different types of forcings. TEX 86 L is a modification of TEX 86 proposed for high-latitude ocean regions. The TEX 86 L-derived temperatures were not different from the alkenone-derived temperatures from the same and nearby sediment samples. During the LGM, alkenone-derived temperatures in the Okhotsk Sea were relatively warm. These and similarly warm alkenone-derived temperatures found at many other sites in the western North Pacific may reflect a shift in the season of biomarker production from early summer and autumn to mid-summer during the LGM as a result of the expansion of the season of sea-ice cover. Empirical orthogonal function (EOF) analysis of alkenone-derived temperatures at 14 sites from the North Pacific suggested substantial cooling between 20 and 14calkyrBP during the deglaciation at 11 of the sites (including 4 sites in the Okhotsk Sea). This dominant EOF mode suggests either an overall seasonal bias in alkenone-derived temperatures or potential shifts in the Haptophyseae production season. The second EOF mode of variability indicated a deglacial warming trend punctuated by millennial-scale cold events, associated with reorganizations of the Atlantic Meridional Overturning Circulation. The SST pattern corresponding to this EOF mode is indicative of millennial-scale meridional shifts of the axis of the westerly jet, which may have affected heat transport across the Kuroshio. Reconstructed temperature changes, in particular in the Okhotsk Sea, provide insight into the conditions that modulated the ventilation history of intermediate waters in the North Pacific.
AB - We estimated sea surface temperatures (SSTs) in the western Okhotsk Sea during the last glacial maximum (LGM) and the last glacial termination from measurements of the alkenone unsaturation index (U K' 37), the Tetra Ether indeX of tetraethers consisting of 86 carbon atoms (TEX 86), and TEX 86 L in piston core sediments, which reveal the climate response of this region to different types of forcings. TEX 86 L is a modification of TEX 86 proposed for high-latitude ocean regions. The TEX 86 L-derived temperatures were not different from the alkenone-derived temperatures from the same and nearby sediment samples. During the LGM, alkenone-derived temperatures in the Okhotsk Sea were relatively warm. These and similarly warm alkenone-derived temperatures found at many other sites in the western North Pacific may reflect a shift in the season of biomarker production from early summer and autumn to mid-summer during the LGM as a result of the expansion of the season of sea-ice cover. Empirical orthogonal function (EOF) analysis of alkenone-derived temperatures at 14 sites from the North Pacific suggested substantial cooling between 20 and 14calkyrBP during the deglaciation at 11 of the sites (including 4 sites in the Okhotsk Sea). This dominant EOF mode suggests either an overall seasonal bias in alkenone-derived temperatures or potential shifts in the Haptophyseae production season. The second EOF mode of variability indicated a deglacial warming trend punctuated by millennial-scale cold events, associated with reorganizations of the Atlantic Meridional Overturning Circulation. The SST pattern corresponding to this EOF mode is indicative of millennial-scale meridional shifts of the axis of the westerly jet, which may have affected heat transport across the Kuroshio. Reconstructed temperature changes, in particular in the Okhotsk Sea, provide insight into the conditions that modulated the ventilation history of intermediate waters in the North Pacific.
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U2 - 10.1016/j.dsr2.2011.12.007
DO - 10.1016/j.dsr2.2011.12.007
M3 - Article
AN - SCOPUS:84857444984
SN - 0967-0645
VL - 61-64
SP - 93
EP - 105
JO - Deep-Sea Research Part II: Topical Studies in Oceanography
JF - Deep-Sea Research Part II: Topical Studies in Oceanography
ER -
