A Record of Precipitation Change for the Past 140ka Based on Diatom Valve Flux in Lake Biwa, Japan

DOI Web Site 11 Citations 80 References
  • Kuwae Michinobu
    Graduate School of Science, Osaka City University Present Address: Center for Marine Environmental Studies, Ehime University
  • Yoshikawa Shusaku
    Department of Geosciences, Faculty of Science, Osaka City University
  • Inouchi Yoshio
    Center for Marine Environmental Studies, Ehime University

Bibliographic Information

Other Title
  • 琵琶湖湖底堆積物の年間珪藻殻堆積量記録からみた過去１４万年間の降水量変動
  • ビワコ コテイ タイセキブツ ノ ネンカン ケイソウカクタイセキリョウ キロク カラ ミタ カコ 14マンネンカン ノ コウスイリョウ ヘンドウ

Search this article

Abstract

For high-resolution reconstruction of climate change in Lake Biwa catchment area, we have analyzed concentration of diatom valve (DVC; valves g-1) and diatom valve flux (DVF; valves cm-2 yr-1) for the past 140ka using the upper part of a 140-m core from Takashima-oki. Time resolution of sampling intervals is 150 to 500 years.<br>The DVF records show higher values during the Holocene (0-7ka) and the last interglacial age (68-135ka) than the present value. By contrast, during the last glacial age (7-68ka) the DVF is relatively low. In addition, the DVF record shows millennial-scale fluctuations over the last 140ka.<br>We have checked the relationship among the DVF, sedimentation rate, and climatic parameters such as temperature, snow depth, and precipitation. We concluded that the DVF reflects diatom productivity, which is strongly controlled by the precipitation level of the preceding summer period.<br>If the DVF can be a proxy for precipitation, the characteristics of the precipitation around Lake Biwa are summarized as follow: the low-level duration during 56-68ka, corresponding to the oxygen-isotope stage 4, is longer than that during the LGM (oxygen-isotope stage 2); after 8ka, the levels gradually rise toward 5.5ka, and increased levels occur at 3 and 5.5ka.<br>The pattern and the episodic events in the record of the DVF in the Lake Biwa sediment can be very closely correlated to the Dansgaard-Oeschger episodes in the North Atlantic climatic record which is revealed from the Greenland ice core. This concordance indicates a possible teleconnection between the precipitation over Japan and temperature over the North Atlantic. The possible mechanism of the teleconnection might be related to changes in westerlies which are driven by temperature changes over the North Atlantic.

Journal

Citations (11)*help

See more

References(80)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top