Reconstruction of glacial-interglacial variations of greenhouse gases from a Greenland deep ice core, NGRIP

为了重建近130年来大气CH_4、N_2O、CO_2和O_2浓度、δ^<15>N （N_2）、δ^<18>O （O_2）和空气含量的变化，我们采用湿空气提取技术对格陵兰北部grip深冰芯进行了分析。我们还根据冰的δ^<18>O的结果和积累模型确定了冰期和冰与被遮挡空气的年龄差异。在修正了由于分子扩散而产生的引力效应后，推导出了上述所有因素的详细时间变化。此外，我们还通过对比north - grip岩心和Dome Fuji深冰岩心的结果，讨论了南北两极各因子变化历史的相似性和差异性。本研究得出的特别有趣的结果是：1。CH4浓度在北极地区始终高于南极地区，且除全新世外，主要依赖于温度。北grip岩心的CO_2浓度明显高于Dome Fuji岩心的CO_2浓度，表明CO2是在格陵兰岛冰中储存空气时与杂质反应产生的新产物。全新世以来，北grip和圆顶富士冰芯的N_2O浓度相当稳定，但在冰期变化较大；4 .北grip和Dome Fuji冰芯的O2浓度极低，表明冰芯底部空气闭塞成冰的过程非常复杂；两个地核的空气含量的时间变化彼此相似，但这种变化与我们目前的知识相冲突，这可能与入射的太阳辐射有关。利用由南北高纬度和低纬度组成的3盒模式分析了北grip和Dome Fuji冰芯CH4浓度差异的时间变化，并成功地阐明了冰期间冰期南北浓度差异的原因。少

In order to reconstruct variations of atmospheric CH_4, N_2O, CO_2 and O_2 concentrations, δ^<15>N of N_2, δ^<18>O of O_2, and air content for the last 130 Kyrs, we analyzed the North-GRIP deep ice core from Greenland using a wet air extraction technique. We also determined ice age and age differences between ice and occluded air based on the results of δ^<18>O of ice and an accumulation model. After correcting for a gravitational effect occurred due to molecular diffusion in firn, detailed temporal variations of all the abovementioned factors were deduced. Furthermore, we also discussed the similarity and differences between variation histories of all factors in north and south polar regions, by comparing the results obtained from the North-GRIP core and the Dome Fuji deep ice core, Antarctica. Especially interesting results derived in this study are that 1.the CH4 concentration was always higher in the north polar region in the south polar region, and those concentration differences … More depended on temperature, except for Holocene, 2.the CO_2 concentrations from the North-Grip core were apparently higher than those from the Dome Fuji core, suggestion that CO2 was newly produced by reacting with impurities during storage of air in ice in Greenland, 3.the N_2O concentrations from the North-Grip and Dome Fuji ice cores were fairly stable for Holocene, but quite variable in the glacial period, 4.the O2 concentrations from the North-Grip and Dome Fuji ice cores were extremely low, suggesting that the process of air occlusion into ice at the bottom of firn is very complex, and 5.that temporal variations of air content from both cores were similar to each other, but such variations are in conflict with our present knowledge, which may be related to incident solar radiation. By analyzing the temporal variations of CH4 concentration differences obtained from the North-Grip and Dome Fuji ice cores using a 3-box model consisting of northern and southern high latitudes and low latitude, we also succeeded in elucidating where was responsible for the north-south concentration differences over the glacial interglacial period. Less