Reconstruction of paleo-environment based on the correlation between paleo-proxies of sediments and observed data

为了定量重建近40万年来琵琶湖及其周边地区的古气候变化，从湖底采集了4个短柱状样，并对沉积物代用指标与仪器数据进行了相关性分析。通过铅-210法测定沉积年龄和各深度的多种分析数据，获得了沉积物的代用指标。气象数据以彦根气象台的数据为基础。沉积物密度、生物硅含量与年平均气温、5月和9月平均气温有较好的相关性。这些事实反映了硅藻盛期湖泊初级生产力主要受平均温度的控制。根据平均温度与沉积物密度或沉积物中生物硅含量的相关关系建立的传递函数，定量地讨论了琵琶湖及其周边地区的气候变化历史。这些研究的结果以15篇评审论文的形式发表，并以64份口头报告的形式提出。

In order to reconstruct paleoclimatic changes quantitatively during the last 400,000 years in and around Lake Biwa, four short cores were recovered from lake bottom surface and correlation between proxies of sediment and equipment data were examined. Proxies of sediment were obtained by determination of sedimentary age using lead-210 method and several kinds of analytical data at each depth. Meteorological data were based on those of Hikone meteorological observatory. Good correlation existed between density of sediments, content of biogenic silica and mean annual temperature or mean temperature of May or September. These facts reflect that primary production in the lake is chiefly controlled by mean temperature during the bloom season of diatoms. Based on the transfer function established by correlation of mean temperature and density of sediment or content of biogenic silica of sediment, quantitative climatic change history of in and around Lake Biwa are discussed. Results of these studies were published as 15 refereed papers and presented as 64 oral presentations.