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Estimation of the concentrations of greenhouse gases in ancient air using ice core analysis

利用冰芯分析估算古代空气中温室气体的浓度

基本信息

批准号：
03452060
负责人：
NAKAZAWA Takakiyo
金额：
$ 2.3万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452060/
关键词：
Ice Core Carbon Dioxide Methane Nitrous Oxide Carbon Isotope Greenhouse Effect Climatic Change 温室効果気体

项目摘要

Precise analysis technique with dry and wet air extractions for the CO_2, CH_4 and N_2O concentrations and delta^<13>C of CO_2 from polar ice core was newly developed independently to reconstruct their ancient levels. The overall precision of the present measurements, including air extraction, was estimated to be better than *1.0 ppmv for CO_2, *10 ppbv for CH_4, *2ppbv for N_2O and 0.05* for delta^<13>C. By using these experimentaltechnique, three ice cores, two from the Antarctica one from Greenland, were analyzed. The results obtained in this study are summarized as follows:1. The CO_2,CH_4 and N_2O concentrations were fairly stable during almost entire period of the Holocene with small fluctuations of the concentration. However, after 250 years BP, the concentrations of these gases increased with time due to human activities.2. The CO_2,CH_4 and N_2O concentrations from an ice core near the Yamato Mountains, Antarctica were obviously lower than the pre-industrial Holocene values, s … More uggesting that this core was formed in the glacial period. During the glacial period, the CO_2 concentrations varied almost out of phase with d13C, which may imply that CO_2 exchange occurred between the atmosphere and the oceans through phytoplankton activities.3. The pre-industrial/pre-agricultural levels of the CH_4 concentration from the Arctic core were higher than 54*10 ppbv than those from the Antarctic core, which is suggested that natural CH_4sources had been stronger in the northern hemisphere than in the southern hemisphere, reflecting the greater extent of boreal compared with austral lands. The present concentration difference of atmospheric CH_4 between northern and southern high latitudes was estimated to be almost three time as much as we have measured for the pre-industrial/pre-agricultural era. From this fact, it was suggested that a large amount of CH_4 was being released into the atmosphere from anthropogenic CH_4 sources especially in the northern hemisphere and/or OH radicals have decreased more rapidly in the northern hemisphere, perhaps due to an increase of the atmospheric CO concentration by fossil fuel combustion. Less

采用干湿空气萃取法对极地冰芯中CO_2、CH_4、N_2O和CO_2的δ ^ C浓度进行了精密分析，并对冰芯中CO_2、CH_4、N_2O和δ ^<13>C浓度进行了古水平重建。包括空气萃取在内的测量精度，CO_2优于 * 1.0ppmv，CH_4优于 *10 ppbv，N_2O优于 * 2 ppbv，Δ ^ C优于0.05*<13>。利用这些实验技术分析了三个冰芯，其中两个来自南极，一个来自格陵兰.本研究的主要结果如下：1.在整个全新世期间，CO_2、CH_4和N_2O的浓度基本稳定，波动幅度较小。然而，在250年BP之后，由于人类活动，这些气体的浓度随着时间的推移而增加。南极大和山冰芯的CO_2、CH_4和N_2O浓度明显低于工业化前全新世的值， ...更多信息说明这个地核形成于冰河时期冰期CO_2浓度与d13 C的变化几乎呈反相变化，这可能意味着CO_2通过浮游植物活动在大气和海洋之间发生了交换.北极柱样在工业化前/农业化前的CH 4浓度水平高于南极柱样的54*10 ppbv，表明北方的天然CH 4源强于南半球，反映了北方陆块比南方陆块更大的程度。据估计，目前北方和南方高纬度地区大气CH_4浓度的差异几乎是前工业/前农业时代的三倍。这一事实表明，在北方半球，大量的CH_4正从人为CH_4源释放到大气中，并且/或者在北方半球，OH自由基下降得更快，这可能是由于化石燃料燃烧增加了大气CO浓度。少