KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 新疆近地表空气干湿时空变化特征及其影响因素 | |
| Alternative Title | Spatial-temporal variation characteristics of surface wet-dry condition and its influencing factors in Xinjiang, China |
| 陈迪桃 | |
| Subtype | 硕士 |
| Thesis Advisor | 李兰海 |
| 2019-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学硕士 |
| Keyword | 新疆 干湿变化特征 相对湿度 Mann-Kendall 趋势检验法 影响因素 Xinjiang Variation characteristics of wet-dry condition Relative humidity Mann-Kendall trend test Influencing factors |
| Abstract | 大气中的水汽不仅是形成降水的必要条件， 也是一种重要的温室气体，对气候变化有着强烈的反馈作用，通常以相对湿度、绝对湿度、比湿、露点温度等指标来表示水汽的含量。其中相对湿度可直接通过站点观测所得，是气温、降水等气象要素的综合表现，可直观地表示区域干湿状况。新疆位于我国西北干旱半干旱区，是距离海洋最远的地区，且地形复杂，气候条件恶劣。 天山山脉更是新疆乃至整个西北干旱区气候和生态环境的重要天然屏障， 是北疆与南疆的天然分界线。 本文旨在探究全球变化背景下，新疆地区近地面湿度的变化趋势，进而阐明新疆水汽含量的变化特征以及区域内的干湿状况变化，并通过影响因素分析，探讨影响新疆地区水汽变化的主要因素。这将是干旱区半干旱区气候变化的重要研究内容之一， 为揭示气象要素变化对生态系统、人类生产生活的影响提供参考，同时对于解决生态脆弱区的干旱问题具有一定的正面意义。本研究基于新疆地区气象站日值数据，通过经验正交函数（EOF）对各个站点的相对湿度及标准化降水蒸散指数（SPEI）进行时空分解，进而对比分析相对湿度与 SPEI 用于评估干湿变化的异同， 利用 Mann-Kendall 趋势检验法阐述新疆地区四季相对湿度变化趋势的空间分布特征，采用敏感性分析法揭示新疆地区相对湿度对平均气温、降水量、蒸散发、日照时数与风速的敏感性，并与贡献率分析相结合探讨引起相对湿度变化的主导因素，此外还通过分析 500hPa 位势高度的气压场与风场之间的差异， 阐释相对湿度高低值年份之间的环流差异。主要结论如下：（1） 相对湿度用于评估干湿变化时与 SPEI 具有相同的变化特征。 EOF 分解的第一特征向量场空间分布均为正值，表明新疆地区的干湿变化具有一致性；第二特征向量场大致以天山为界， 南北疆表现为相反的特征值，表明北疆的干湿变化趋势与南疆相反的两种分布型式，即北疆湿南疆干，或者北疆干南疆湿的分布型式。（2）北疆与南疆地区的相对湿度的年际变化均呈现出先上升再下降的趋势，2000 年为其趋势变化的转折点，但北疆的相对湿度明显大于南疆，即北疆更为湿润。（3）年平均相对湿度呈显著上升与显著下降趋势的站点大致持平，春季平均相对湿度呈显著上升趋势的站点明显少于显著下降趋势的站点，而夏、秋、冬三季相对湿度变化趋势则以显著上升趋势占主导。（4）新疆地区相对湿度对实际蒸散发、日照时数、气温及风速均为负敏感，对降水量为正敏感。北疆全年相对湿度对各气象因子的敏感程度依次为日照时数>实际蒸散量>气温>风速>降水量，南疆全年相对湿度对各因子的敏感程度依次为日照时数>实际蒸散量>风速>气温>降水量。空间分布上， 相对湿度对实际蒸散量、日照时数敏感系数绝对值高值区位于新疆东部哈密与吐鲁番地区，降水量敏感系数绝对值高值区位于天山北坡地区，气温敏感系数绝对值高值区位于天山南坡与昆仑山北坡地区，平均风速敏感性程度自中部向南北两侧递减。（5）气温、风速分别是影响北疆、南疆地区全年相对湿度变化的主导因子。北疆春、夏、秋三季气温对相对湿度的贡献率最大，冬季则是风速；南疆四季气温均对相对湿度的贡献率最大。空间分布上，实际蒸散量贡献率高值区集中于天山中段地区，降水量和风速贡献率高值区位于塔里木盆地与天山东段地区，日照时数的高值区集中于北疆，气温贡献率高值区位于天山南北坡地区。（6） 环流分析表明，新疆地区相对湿度受西风环流、局地气旋环流以及副热带高压等环流因素的共同影响，当西风环流增强、局地气旋环流增强或副热带高压削弱时，新疆地区相对湿度有明显的增强作用，水汽含量更充足、区域更湿润。 |
| Other Abstract | Water vapor is one of the most vital components in the stratosphere andtroposphere. On the one hand, it is a necessary condition for precipitation. On the otherhand, water vapor is an important green-house gas which is a key driving force ofclimate change. Playing an important role in global warming and plant growing, relativehumidity (RH) has profound impacts on production and living, and can be looked uponas an integrated indicator for evaluating the wet-dry conditions in the arid and semiarid area. Xinjiang Uygur Autonomous Region is located in the northwest of China. Itis characterized by a basin-and-range geomorphologic pattern. There are threemountains which are located in the northernmost, middle and the southernmost ofXinjiang, respectively. And Junggar Basin, Tarim Basin and Tulufan-Hami Basin aredistributed among these mountains. Due to the blocking effect of the TianshanMountains, there are obvious differences in climate between the northern and southernXinjiang regions. This study aimed at revealing the spatial-temporal characteristics andits influencing factors of wet-dry conditions under climate change in Xinjiang. It willbroaden the understanding in the area of climate change in arid and semi-arid area, it ismeaningful for understanding the aridification in ecotone under global change.The similarities and differences between RH and standard precipitationevapotranspiration index (SPEI) in evaluating wet-dry changes was showed byempirical orthogonal function (EOF). The spatial characteristics of RH in Xinjiangwere inspected using Mann-Kendall trend test. In addition, sensitivity coefficient andrelative contribution were calculated to assess the influencing factors on RH. The mainconclusions were as follows:(1) It was similar results from RH and SPEI through EOF. EOF1 showed positivevalues over the Xinjiang, meaning that there were similar trends of wet-dry changes inXinjiang. EOF2 showed two separated centers of opposite signs over the North Xinjiang and South Xinjiang respectively.(2) Interannual variation in RH was upward and then downward. The turning pointof the change of RH was the year 2000. And there was more humid in North Xinjiangthan that in South Xinjiang.(3) RH mainly showed a significant downtrend in spring, while it mostly showeda significant uptrend in summer, autumn and winter in Xinjiang.(4) The results of sensitivity analysis indicated that RH was negatively related totemperature, actual evapotranspiration, wind speed and sunshine duration, but it has apositive relationship to precipitation. RH was the most sensitive to sunshine duration,while precipitation was the most insensitive in Xinjiang. Spatially, the strong sensitivityarea of actual evapotranspiration and sunshine duration, precipitation and wind speed,temperature were located in Hami-Tulufan, Tianshan Mountains and south slope ofTianshan Mountains and north slope of Kunlun Mountains, respectively.(5) Results from contribution analysis that the impacts of temperature and windspeed on RH were greater than that of others variables in North Xinjiang and SouthXinjiang, respectively. The highest contribution area of actual evapotranspiration wasdistributed in the middle Tianshan Mountains, while the high contribution area ofprecipitation and wind speed were in Tarim Basin and eastern Tianshan Mountains. Forsunshine duration and temperature, their high contribution area was in the whole ofNorth Xinjiang and the north and south slopes of the Tianshan Mountains, respectively.(6) Changes in large scale atmospheric circulation suggested that the enhancedwesterly circulation, enhanced local cyclonic circulation and weakening of SubtropicalHigh over the Eurasian continent were the vital circulation factors that has contributedto the increased RH in Xinjiang. |
| Subject Area | 自然地理学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15318 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 陈迪桃. 新疆近地表空气干湿时空变化特征及其影响因素[D]. 北京. 中国科学院大学,2019. |
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