Temporal fluctuation of the position of the sea surface temperature boundary in the Japan Sea during the Holocene
Abstract
The Japan Sea is one of the marginal seas in the northwestern Pacific and its sediments potentially have high-resolution records of the regional climate change around the East Asia. The Tsushima Warm Current (TWC) is the only current flowing into the sea and plays an important role on controlling the environment of the Japan Sea by supplying heat and salt. After passing through the Tsushima Strait, the TWC divides into three branches. The First and Second Branches of the TWC flow northeastward along the Japanese coast. Whereas the Third Branch of the TWC flows northward along the eastern margin of the Korea Peninsula, turns eastward along the sub-polar front at around 40°N, and merges with the FBTWC and SBTWC. Previous studies reconstructed fluctuations of sea-surface temperatures (SST) in the Japan Sea based on alkenone temperature index and discussed the linkage between volume transport change in TWC and East Asian Summer Monsoon intensity. However, none of previous studies have provided SST in the central part of the Japan Sea and presented direct evidence of north-south fluctuations of the SST boundary. So, it is important to reconstruct the position of the SST boundary in the central part of the Japan Sea in order to understand volume transport of the TWC and air-sea interaction. This study reconstructs alkenone-based SST in the central part of the Japan Sea with the 250 year time resolutions and compares the result with SST changes in the southern part of the Japan Sea in order to examine north-south SST gradient. Based on north-south SST gradient, we will demonstrate how the position of the SST boundary fluctuates. The reconstructed alkenone temperatures in the central part of the Japan Sea show millennial-scale fluctuations with 5 degrees Celsius amplitude which is larger than in the southern part. North-south temperature gradient show similar patterns, but there were the north-south temperature reversal period at 1ka, 4ka, 9ka.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMPP41A1985A
- Keywords:
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- 0473 BIOGEOSCIENCES / Paleoclimatology and paleoceanography;
- 4954 PALEOCEANOGRAPHY / Sea surface temperature