scholarly journals Centennial to millennial climate variability in the far northwestern Pacific (off Kamchatka) and its linkage to East Asian monsoon and North Atlantic from the Last Glacial Maximum to the Early Holocene

2016 ◽  
Author(s):  
Sergey A. Gorbarenko ◽  
Xuefa Shi ◽  
Min-Te Chen ◽  
Galina Yu. Malakhova ◽  
Aleksandr A. Bosin ◽  
...  

Abstract. High resolution reconstructions based on productivity proxies and magnetic properties measured from sediment core 41-2 (off Kamchatka), reveal prevailing centennial-millennial productivity/climate variability in the northwestern (NW) Pacific from the Last Glacial Maximum (LGM) to the Early Holocene (EH). The core age model is established by AMS 14C dating using foraminifer shells from the core and by correlating the productivity cycles and relative paleomagnetic intensity records with those of well-dated nearby core, SO-201-12KL. Our results show a pronounced feature of centennial-millennial productivity/climate cycles of the NW Pacific had occurred synchronicity with the summer East Asian Monsoon (EAM) at sub-interstadial scale during the LGM (3 cycles), Heinrich Event 1(3 cycles), and Bølling/Allerød warming (4 cycles), and over the EH (3 cycles). Our comparison of the centennial-millennial variability to the Antarctic EDML (EPICA Dronning Maud Land) ice core suggests a “push” effect of Southern hemisphere temperature gradients on the summer EAM intensifications. Besides the linkages of NW Pacific high productivity and summer EAM, we observed that five low productivity cycles during EH are nearly synchronous with cooling in Greenland, weakening of the summer EAM, and decreases in solar irradiance. We propose that such centennial-millennial productivity/climate variability in the NW Pacific and sequence of sub-stadial/interstadials in the EAM from the LGM to EH are a persistent regional features, synchronous with the Greenland/North Atlantic short-term changes. We speculate that such climate synchronicity was forced also by changes in Atlantic meridional overturning circulation coupled with Intertropical Convergence Zone shifting and the northern westerly jets reorganization.

2017 ◽  
Vol 13 (8) ◽  
pp. 1063-1080 ◽  
Author(s):  
Sergey A. Gorbarenko ◽  
Xuefa Shi ◽  
Galina Yu. Malakhova ◽  
Aleksandr A. Bosin ◽  
Jianjun Zou ◽  
...  

Abstract. High-resolution reconstructions based on productivity proxies and magnetic properties of core LV63-41-2 (off Kamchatka) reveal prevailing centennial productivity/climate variability in the northwestern (NW) Pacific from the Last Glacial Maximum (LGM) to the early Holocene (EH). The age model of the core is established by AMS 14C dating and by projections of AMS 14C data of the nearby core SO-201-12KL through correlation of the productivity proxies and relative paleomagnetic intensity. The resulting sequence of centennial productivity increases/climate warming events in the NW Pacific occurred synchronously with the East Asian summer monsoon (EASM) sub-interstadials during the LGM (four events), Heinrich Event 1 (HE1) (four events), Bølling–Allerød (B/A) warming (four events), and over the EH (four events). Remarkable similarity of the sequence of the NW Pacific increased-productivity events with the EASM sub-interstadials over the LGM-HE1 implies that the Siberian High is a strong and common driver. The comparison with the δ18O record from Antarctica suggests that another mechanism associated with the temperature gradient in the Southern Hemisphere may also be responsible for the EASM/NW Pacific centennial events over the LGM-HE1. During the B/A warming and resumption of the Atlantic Meridional Overturning Circulation (AMOC), clear synchronicity between the NW Pacific, EASM and Greenland sub-interstadials was mainly controlled by changes in the atmospheric circulation. During the EH the linkages between solar forcing, ocean circulation, and climate changes likely control the synchronicity of abrupt climate changes in the NW Pacific and North Atlantic. The sequence of centennial events recorded in this study is a persistent regional feature during the LGM-EH, which may serve as a template in high-resolution paleoceanography and sediment stratigraphy in the NW Pacific.


2010 ◽  
Vol 23 (18) ◽  
pp. 5030-5038 ◽  
Author(s):  
Dabang Jiang ◽  
Xianmei Lang

Abstract During glacial periods, the East Asian monsoon is typically thought to have been stronger in boreal winters and weaker in boreal summers. It is unclear, however, whether this view is true at larger scales and to what extent the East Asian monsoon responds to glacial conditions as a whole. Using all experiments conducted as part of the Paleoclimate Modeling Intercomparison Project (PMIP), this paper examines East Asian monsoon climatology during the Last Glacial Maximum (LGM), around 21 000 calendar years ago. In contrast to conclusions drawn from sparse proxy data, the intensity of the East Asian winter (December–February) monsoon (EAWM) during the LGM, as measured by regionally averaged meridional wind speed at 850 hPa, was found to vary both in sign and magnitude, with reference to baseline climate, across the PMIP simulations. It strengthened in 10 out of the 21 models but weakened in the remaining 11 models, with an average weakening of 4% for the 21-model ensemble mean (15% for the ensemble mean of the 14 models with computed sea surface temperatures). At the subregional scale, the LGM EAWM strengthened north of about 30°N but weakened south of this region in East Asia, which can be explained by changes in surface temperature. On the other hand, all of the 14 models chosen in this study consistently simulated a weaker than baseline East Asian summer (June–August) monsoon during the LGM, with an average weakening of 25%.


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