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RECONSTRUCTION OF CLIMATE AND ATMOSPHERIC TRANSPORT BY MEANS OF ICE CORE ANALYSES IN THE NORTH PACIFIC

通过冰芯分析重建北太平洋的气候和大气输送

基本信息

批准号：
16403005
负责人：
SHIRAIWA Takayuki
金额：
$ 6.21万
依托单位：
Research Institute for Humanity and Nature (2005)Hokkaido University (2004)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

We analyzed the ice core drilled at Mt.Wrangell in 2004. The analyses were made for the upper 100m of the 217-m long ice core. They are hydrogen isotope ratio (0-50m), major ions (0-50m), dust concentration (0-80m), X-ray density (0-100m) and tritium (0-50m). Trace elements were also measured for the Mt.Logan ice core which we drilled in 2002. Following results are obtained by this research project :1.Clear seasonal cycles are found for the upper 50m of the ice core in the cases of hydrogen isotope ratio, dust and tritium concentrations. The peaks appeared in summer for delta D and spring for the dust and tritium concentrations.2.Standard deviation in the X-ray density variations are negatively related with delta D suggesting that the high density variations occur in spring-summer period when snow falls rather intermittently.3.Concentration in dust becomes higher in spring and lower in the other periods. It is also found that the dust concentration has been increasing since 2000, which coincides with observation of dust falls in Japan.4.Tritium concentration in the Wrangell ice core shows a beautiful seasonal cycle having the highest peak in spring. This is due to the so-called "Stratosphere-Troposphere Exchange" in air mass and the concentration can be a promising indication of atmospheric disturbances in spring.5.Sodium flux is positively correlated with Pacific Decadal Oscillations suggesting the atmospheric-oceanic interaction in the North Pacific.6.Annual Iron fluxes during the period 1980-2000 in the Logan ice core were varying from several μg/square m to 80μg/square m. The source of the iron can be ascribed to Asian dust and the nearby volcanoes.7.Annual accumulation rates both in the Wrangell ice core and the Logan ice core showed clear negative relationship for the last 100 years, suggesting that the PDO has impacted mountain precipitation significantly.

我们分析了2004年在弗兰格尔山钻探的冰芯。分析是在217米长的冰芯的上100米进行的。它们是氢同位素比值（0-50m）、主离子（0-50m）、粉尘浓度（0-80m）、x射线密度（0-100m）和氚（0-50m）。我们在2002年钻探的洛根山冰芯中也测量了微量元素。本课题主要研究结果如下：在冰芯上部50m处，氢同位素比、尘埃和氚浓度具有明显的季节循环。δ D浓度峰值出现在夏季，而尘埃和氚浓度峰值出现在春季。x射线密度变化的标准差与D呈负相关，表明高密度变化发生在春夏季，此时降雪较为间歇性。沙尘浓度在春季较高，其他时期较低。同时发现，2000年以来扬尘浓度呈上升趋势，这与日本降尘观测结果相吻合。Wrangell冰芯中的氚浓度呈现出美丽的季节循环，在春季达到峰值。这是由于气团中所谓的“平流层-对流层交换”，而这种浓度可能是春季大气扰动的一个有希望的指示。钠通量与太平洋年代际振荡呈正相关，表明北太平洋的大气-海洋相互作用。1980 ~ 2000年洛根冰芯的年铁通量在几~ 80μg/ m2之间变化，铁的来源可能是亚洲沙尘和附近的火山。近100年来Wrangell冰芯和Logan冰芯的年累积速率均呈明显的负相关，表明PDO对山地降水有显著影响。