MILLENNIAL-SCALE CHANGES IN SEA SURFACE TEMPERATURES AND INTERMEDIATE WATER CIRCULATION IN THE NORTHWEST PACIFIC DURING THE PAST 20,000 YEARS

• Main Author: Max, Lars
• Format: Thesis
• Language: unknown
• Published: Universität Bremen 2012
• Subjects: Greenland; North Atlantic; Sea ice; Subarctic
• Online Access: https://epic.awi.de/id/eprint/35099/; https://epic.awi.de/id/eprint/35099/1/PhD-thesis_Max_2012.pdf; http://suche.suub.uni-bremen.de/cgi-bin/CiXbase/brewis/CiXbase_search?act=peid&XML_STYLE=/styles/url.xml&peid=D00102803&CID=&index=L&Hitnr=3; https://hdl.handle.net/10013/epic.43156; https://hdl.handle.net/10013/epic.43156.d001

During the late Pleistocene to Holocene transition global climate changed dramatically. In particular, during the end of the late Pleistocene, the large-scale shift from the last glacial state to the recent interglacial state took place (between 18,000–11,000 years ago) and was accompanied by millennial- scale climate fluctuations that are well known from the North Atlantic realm. On the other hand, detailed paleoceanographic reconstructions of the subarctic North Pacific climate history are scarce and patchy, thus an incomplete picture of short-term climate fluctuations of the late Pleistocene to Holocene remains so far. The principal aim of this thesis was the reconstruction of the poorly studied (millennial-scale) climate variability of the subarctic northwest Pacific, which has become more into focus of climate research, as it is believed that past climate dynamics in this region are a key to gain more understanding in the mechanisms that drove late Pleistocene climate dynamics. For this purpose, a variety of different geochemical proxies were used for detailed paleoceanographic investigations in order to give detailed insights into past dynamics of sea surface temperatures, sea-ice variability and intermediate water ventilation characteristics of the northwest Pacific realm during the past 20,000 years. From high-resolution SST records it has been shown that the deglacial SST changes in the far northwest Pacific realm matched the climate variability in other parts of the North Pacific and beyond that, were remarkably similar to the timing and nature of the North Atlantic/Greenland temperature variability. From this, a close linkage to deglacial variations in the Atlantic Meridional Overtuning Circulation was inferred, which invoked rapid atmospheric teleconnections to allow a quasi- synchronous (on centennial time-scales) SST development between the North Atlantic and the North Pacific. Reconstructions of past sea-ice variability points to strong changes in sea-ice extent and a close coupling to SST ...