Knowledge Resource Center for Ecological Environment in Arid Area
| 祁连山-天山雪冰中粉尘的元素示踪与亚洲粉尘传输 | |
| 其他题名 | Asian dust transport and element tracing of dust in ice/snow from Qilian Shan and Tien Shan |
| 张成龙 | |
| 出版年 | 2012 |
| 学位类型 | 博士 |
| 导师 | 邬光剑 ; 田立德 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 本研究选择了青藏高原北部的祁连山敦德冰帽、七一冰川、冷龙岭冰川，以及天山乌鲁木齐河源1号冰川（天山1号冰川）为研究区域。在祁连山地区，我们采集了七一冰川和冷龙岭冰川表层雪样品，并对包括已有敦德浅冰芯在内的所有样品中粉尘的稀土元素浓度及组成特征，以及敦德冰芯粉尘Sr-Nd同位素组成特征等方面的分析；在天山1号冰川区，每周一次或每两周一次地采集表层雪样品（2006－2007年），并开展了雪冰中常量元素的溶解率，以及不溶粉尘的稀土元素组成特征等方面的研究。在此基础上，利用稀土元素及同位素示踪法对祁连山-天山雪冰中粉尘的来源进行探讨，结合NCAR/NCEP再分析气象数据、MODIS卫星遥感数据、CALIPSO激光雷达数据以及HYSPLIT反向气团轨迹模拟等多方面的资料，探讨了高空亚洲粉尘的主要传输路径。\n 祁连山敦德冰芯粉尘及七一冰川和冷龙岭雪冰中粉尘的稀土元素球粒陨石标准化分配模式均表现为轻稀土相对富集和Eu明显负异常。通过稀土元素示踪以及区域大气环流分析，发现塔克拉玛干沙漠可能是祁连山西段敦德冰帽和七一冰川重要的粉尘源区。此外，敦德冰帽中部分粉尘还可能接收来自柴达木盆地的部分粉尘，而七一冰川雪冰中粉尘则还可能受到来自库姆塔格沙漠及戈壁粉尘混合输入。敦德冰芯中粉尘的Sr-Nd同位素研究表明，敦德冰芯中粉尘可以较好表征远距离传输的亚洲粉尘，进一步证实了塔克拉玛干沙漠是北太平洋风成沉积和格陵兰雪冰中粉尘的主要源区。\n 天山乌鲁木齐河源1号冰川表层雪中粉尘的稀土元素组成特征均表现为轻稀土富集和Eu明显负异常；尽管雪冰中粉尘质量浓度存在明显的季节变化，但粉尘中稀土元素组成稳定且没有季节变化。稀土元素示踪和反向气团轨迹模拟研究表明，天山1号冰川表层雪中粉尘主要来自于古尔班通古特沙漠及萨雷耶西克阿特劳沙漠等中亚干旱区，而塔克拉玛干沙漠粉尘有时也可以在此地区沉降但其贡献率相对较小。雪冰中Na、K、Mg和Ca等元素溶解率的分析表明，元素Ca 和Na 较元素Mg和K更易溶于雪冰融水中；通过元素溶解率的比较发现这四个元素在雪冰中的淋溶序列为：Ca>Na>Mg>K。\n 气象资料、遥感数据和气团轨迹模拟等研究表明，塔克拉玛干沙漠及周边地区是亚洲粉尘非常重要的释放源区之一。亚洲粉尘的垂直分布特征表明，粉尘可以到达海拔8~10 km高空。典型沙尘暴事件的研究显示，塔克拉玛干沙漠粉尘在冷锋系统影响下扬起，而后随区域上升气流作用下越过周边高山升至对流层中上部（5km以上），最终被高空西风携带至其下风区沉降。 |
| 英文摘要 | In this study, the ice/snow samples were collected from the Dunde ice cap, the Qiyi glacier and the Lenglongling glacier on Qilian Mountain in the Northern Tibetan Plateau, as well as the Urumqi No.1 (UG1) glacier on Tien Shan. The characteristics of rare earth elements (REE) for the dust in ice/snow from Qilian Mountain were analyzed; moreover the Sr-Nd isotopic composition of the Dunde ice dust was studied in this work. At the UG1 area, the solubility of major elements and the rare earth elements composition of the dust materials in the surface snow were measured. These REE characteristics in the ice/snow were used to trace the source of the dust materials. In addition, the reanalysis data from NCAR/NCEP, MODIS remote sensing data, CALIPSO Lidar data and HYSPLIT model were combined to discuss the source and the possible transport pattern of the Asian dust.\nThe dust in ice/snow from the Dunde ice cap, the Qiyi glacier and the Lenglongling glacier on Qilian Mountain have similar REE chondrite-normalized distribution patterns, with relative enrichment in light REE and negative Eu anomaly. The REE footprint in the dust and regional atmospheric circulation characteristics indicate that Taklimakan desert might be an important dust source of the Dunde ice cap and the Qiyi glacier. However, the Badain Jaran desert and Tengger desert might hardly provide plenty of dust particles for the high alpine ice/snow in Qilian Mountain. In addition, the Qaidam basin dust might also transport to the Dunde ice cap and the Kumtag desert and Gobi might also provide dust materials for the Qiyi glacier. The comparison of Sr-Nd isotopic composition between in Dunde dust and in the potential deposition of Asian dust containing the Pacific deposition, Greenland ice/snow dust, and China loess, suggest that Dunde dust is a good analogue for long-range transported Asian dust.\nThe dust in UG1 snow has REE chondrite-normalized distribution patterns with relative enrichment in light REE and negative Eu anomaly. The REE composition of the dust materials remained uniform without seasonal variation through the two-year sampling periods. The REE footprint of the dust and back trajectories analysis suggest that the dust materials in UG1 snow primary be from Gurbantunggut desert and the central Asian deserts, while the contribution of Taklimakan desert might be very small. The elemental speciation study for Na, K, Mg, and Ca in UG1 snow indicated that the dominant fraction of Ca is dissolved phase, while the proportion of soluble phase is much lower for Na, K, and Mg. \nMultiple studies about Asian dust by meteorology, remote sensing and back trajectory suggest that Taklimakan desert might be an important dust source and the atmospheric dust loading over the Northern Tibetan Plateau is higher than that over the Southern. Asian dust there multiple layer over the dust source regions and even could be uplifted to 8~10 km upper troposphere. The uplift and transport mechanism of Taklimakan desert dust might be first released into the atmosphere by the cold front system, and then could be uplifted up to mid-upper troposphere along the slope of Tibetan Plateau with the help of regional updraft, at last the high altitude dust might be transported over the Qilian Mountains and beyond. |
| 中文关键词 | 祁连山-天山 ; 雪冰 ; 粉尘 ; 元素示踪 ; 传输 |
| 英文关键词 | Qilian Mountain-Tiean Shan ice/snow dust element tracing transport |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院青藏高原研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287040 |
| 推荐引用方式 GB/T 7714 | 张成龙. 祁连山-天山雪冰中粉尘的元素示踪与亚洲粉尘传输[D]. 中国科学院大学,2012. |
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