Knowledge Resource Center for Ecological Environment in Arid Area
| 基于冰芯记录与卫星反演的青藏高原气溶胶变化研究 | |
| 其他题名 | THE AEROSOL CHANGE RESEARCH OVER THE TIBETAN PLATEAU USING THE ICE CORE RECORDS AND SATELLITE REMOTE SENSING DATA |
| 宫晓倩 | |
| 出版年 | 2012 |
| 学位类型 | 硕士 |
| 导师 | 李玉强 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 冰芯中的微粒记录是恢复过去大气粉尘变化的独特信息，而卫星资料是研究大范围粉尘特性的有效方法，尤其是在地面观测稀少的青藏高原地区。本文选取青藏高原的西部（慕士塔格）、中部（唐古拉）、南部（珠峰、达索普和宁金岗桑）为研究地点，结合遥感数据（气溶胶指数和气溶胶光学厚度）和冰芯记录（粉尘质量浓度与沉积通量）探讨过去几十年来青藏高原大气粉尘在时间上和空间上的变化。研究发现，冰芯中粉尘质量浓度表现为高原中部>高原西部>高原南部，而沉积通量表现为高原西部>高原中部>高原南部。青藏高原上气溶胶指数与光学厚度从北向南、从西向东减少，靠近塔克拉玛干沙漠的地区数值最大，高原南部地区最低，与西风环流在高原的传输路径和源区的地理分布一致，并且与冰芯粉尘沉积通量记录变化相一致。\n 慕士塔格冰芯的沉积通量有降低的趋势，唐古拉粉尘多年来变化趋势平稳，高原南部粉尘有降低的变化趋势。遥感数据显示，高原各地粉尘高值均发生在春季，而粉尘低值高原西部发生在冬季，中部发生在秋季，南部发生在夏秋季节。\n 通过冰芯记录（沉积通量）与观测的卫星记录的对比及HYSPLIT气团反向轨迹追踪，发现高原南部粉尘来源于伊朗沙漠以及南亚塔尔沙漠。\n 通过冰芯中的粉尘沉积通量记录与气溶胶指数的相关分析，发现在年尺度上仅有唐古拉地区表现出较好的相关性，而在其它地区无明显相关关系。经过三点滑动平均后，高原各地有显著的相关关系：慕士塔格地区相关系数为0.49（P=0.13）；唐古拉地区的相关系数为0.87（P<0.001）；宁金岗桑地区的相关系数是0.68（P=0.03）。这种相关性为通过冰芯记录来反演更长时间尺度的青藏高原上气溶胶指数提供了基础。本文通过两种方法（三元函数法与比较相关系数法）反演的气溶胶指数图与原始图进行比较，发现利用比较相关系数法反演的数据更能反映真实的情况，而且结果与真实值非常接近。因此，利用慕士塔格、唐古拉以及宁金岗桑三个地区冰芯记录通过比较相关系数法反演了1970至1978年的年均青藏高原大范围的粉尘分布。说明利用冰芯粉尘记录可以恢复过去大范围的粉尘特征。\n 对比1979年至1992年负值时的SOI（El Nino年）与同期青藏高原年均AI发现，两者存在显著的相关关系，相关系数达到0.78，P值达到0.007。这说明发生厄尔尼诺事件时，青藏高原大气中的粉尘含量偏少，这可能与厄尔尼诺年高原裸露地表减少和弱的西风强度造成粉尘活动减弱有关。并且对ENSO过程研究发现，高原西部地区粉尘沉积通量开始年为正异常，次年为负异常，可能与降水量变化有关；高原南部地区冰芯粉尘沉积通量在厄尔尼诺开始年为负异常，次年为正异常，可能与欧亚大陆雪盖面积异常有关；高原中部地区无明显变化规律。说明高原粉尘受到厄尔尼诺事件影响，并且高原的西部南部地区受到影响不同。\n 通过北大西洋涛动指数与冰芯粉尘沉积通量对比分析，可以发现北大西洋涛动强时，西风环流加强，会使高原西部粉尘含量升高，增加粉尘沉积量，而其对高原南部粉尘影响不显著，说明青藏高原上的冰芯粉尘含量要受到北大西洋涛动事件的影响。 |
| 英文摘要 | Particle records of ice cores are the unique information which can recover atmospheric dust change in the past, while using remote sensing data is a very effective way to research the characteristics of dust in a large scope, especially on the Tibetan Plateau where ground-based observations are scarce. Selecting the west section (Muztagata), the central section (Tanggula), and the south part (Mt. Qomolangma, Dasuopu and Noijinkansang) of the Tibetan Plateau for the research sites and combining with the remote sensing data (aerosol index and aerosol optical depth) and ice core records (dust concentration and flux), the temporal and spatial changes of the atmospheric dust on the Tibetan Plateau are discussed in this paper. It is found that dust concentration from the central part of the Tibetan Plateau is greater than that from the west which is greater than that of the south. However, dust flux from the west part of the Tibetan Plateau is greater than that from the central part while that from the south is the lowest. Aerosol index and optical depth decreases from north to south and from west to east over the Tibetan Plateau, and the maximum aerosol index value takes place near the Taklimakan desert, and the minimum one takes place on the south of the Tibetan Plateau, in line with the westerly circulation path in the highlands and the geographical distribution of the source areas, in accord with dust flux in ice cores.\n The dust flux in Muztagata ice core has the decreasing trend and the change of dust from Tanggula is smooth, while the dust content from the south of the Tibetan Plateau has the decreasing trend. Remote sensing data shows the highest value of AI around the plateau appears in spring, while the lowest value of AI in the west takes place in winter, which in the central part does in autumn and in the south does in summer and autumn.\n Through contrasting the ice core records (dust flux) and the global satellite data and the HYSPLIT, it is found that the dust over the south of the Tibetan Plateau comes from the Iran Desert and the Thar Desert. \n Through the relevant analysis between the dust flux records and aerosol index, we find there is good correlation in the Tangula area only in the year scale, and no obvious correlations can be seen in the other areas. After 3-years moving average, the correlation is prominent all over the plateau: the correlation coefficient is 0.49 (P=0.13) in the Muztagata, 0.87 (P<0.001) in the Tanggula and 0.68 (P=0.03) in the Noijinkansang. These correlations provide the basis for inverting aerosol index through the ice core records in longer time scales on the Tibetan Plateau. This article compares the original maps with aerosol index maps inverted by using the two methods (three variables function and comparing correlation coefficient), we find that the inversion data using the correlation coefficient method reflects the real situation better, and the results are closed to the real value. Therefore, by comparing correlation coefficient method, using the ice core records of Muztagata, tangula and Noijinkansang, this paper inverses a wide range of dust distribution of the Tibetan Plateau from 1970 to 1978. Using dust records of ice cores, we can recover dust features of a wide range in the past.\n Comparing the negative SOI (El Nino years) with the AI of the Tibetan Plateau from 1979 to 1992, we find that there is a significant correlation, correlation coefficient reaches 0.78 (P=0.007). When El Nino events happened, the atmosphere over the Tibetan Plateau contained few dust. That may due to the reducing bare surface area of the Tibetan Plateau and weak westerlies strength which leads to dust activities weakly. Studying ENSO process, we find that the dust flux on the west of the Tibetan Plateau reveals positive anomaly in started years of El Nino and negative anomaly in the next year, that may be linked to rainfall changes; the dust flux on the south reveals negative anomaly in started years and positive anomaly in the next year, that may be related to Eurasian snow cover area anomalies, but there is no evident changing-regular in the central part. El Nino events influence dust and produce different effects between the west and south of the plateau.\n After comparative analysis between the NAO index and dust flux，we find that the strong NAO can strengthen the westerlies circulation and then the dust content of the west of the Tibetan Plateau is increasing, but it has no significant influence for the dust of the south. The NAO influence the dust content of the Tibetan Plateau. |
| 中文关键词 | 青藏高原 ; 气溶胶指数 ; 气溶胶光学厚度 ; 粉尘质量浓度与沉积通量 |
| 英文关键词 | Tibetean Plateau Aerosol Index Aerosol Optical Depth Dust Concentration and Flux |
| 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/2XILL650/287113 |
| 推荐引用方式 GB/T 7714 | 宫晓倩. 基于冰芯记录与卫星反演的青藏高原气溶胶变化研究[D]. 中国科学院大学,2012. |
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