基于主成分分析的青藏高原多年冻土区高寒草地土壤质量评价   总被引：5，自引：1，他引：4  

刘鑫  王一博  吕明侠  孙岩  杨文静  赵金鹏 《冰川冻土》2018,40(3):469-479

土壤质量评价是提高对土壤质量理解的关键环节。为了了解青藏高原多年冻土区高寒草地土壤质量的基本情况,在青藏高原腹地西大滩至安多地区,根据不同海拔梯度和植被盖度共采集了154个土壤样品。通过主成分分析（PCA）法确定了影响青藏高原多年冻土区高寒草地土壤质量的最小数据集（MDS）：全氮、全磷、全钾。根据影响土壤质量的最小数据集对青藏高原多年冻土区高寒草地土壤质量进行评价,得出了不同海拔、不同植被盖度下的土壤质量指数（SQI）。通过对不同海拔、不同植被盖度的土壤质量指数进行对比研究表明：随着海拔的升高,SQI呈增加的趋势,即海拔4 300～4 600 m（0.270±0.043） < 海拔4 600～4 900 m（0.326±0.061） < 海拔4 900～5 200 m（0.410±0.075）;随着植被盖度的增加,SQI也呈现增加的变化趋势,即植被盖度小于50%（0.262～0.265） < 植被盖度大于50%（0.336～0.344）。在分别考虑了有机质、盐分、土壤水分对土壤质量的影响下得出的土壤质量指数值与基于最小数据集得到的土壤质量指数相一致,说明基于主成分分析的最小数据集可以对青藏高原多年冻土区高寒草地土壤质量做出较准确的评价。  相似文献   

基于小波分析与Mann-Kendall法的岩溶大泉动态研究   总被引：1，自引：1，他引：0  

迟光耀  邢立亭  侯新宇  黄林显  杨奕  张文静 《中国岩溶》2018,37(4):515-526

研究地下水动态是认识地下水资源的有效手段。根据1956－2013年济南岩溶泉域大气降水及地下水水位动态监测资料,采用小波分析法、Mann-Kendall趋势检验、突变检验法研究了58个水文年泉水位对大气降水的响应,可以看出:（1）大气降水和泉水位呈现出多尺度的变化特征,长时间尺度上两者的变化周期基本相同,变化周期为16年和12年,说明大气降水对泉水位有直接影响;（2）在1956—2013年,济南泉域地下水水位具有0.65 m·（10a）-1的年际显著下降趋势,但降水具有12.65 mm·（10a）-1的不显著上升趋势,说明在人为因素影响下泉水动态的影响因素的权重发生了变化;（3）大气降水在1999年发生突变,1999年之后年降水为增加趋势;而地下水水位突变年份为1967年,1967年以后水位持续降低,2004年以后水位快速上升,泉水位未来趋势应与降水保持一致,呈上升趋势,说明大气降水并非泉水动态的唯一影响因素;（4）通过建立不同时段的多元回归模型,表明近58年来地下水水位的主要影响因素由大气降水到人工开采之间的转换,同时验证了小波分析和Mann-Kendall法研究地下水动态的适宜性和可靠性,也为济南市的保泉提供了参考依据。   相似文献   

Study on Water Internal Recycle Process and Mechanism in Typical Mountain Areas of Inland Basins,Northwest China: Progress and Challenge     

Yongjian Ding  Shiqiang Zhang 《地球科学进展》2018,33(7):719-728

The water resource and its change of mountainous area are very important to the oasis economic system and ecosystem in the arid areas of northwest China. Accurately understanding the water transfer and circulation process among vegetation, soil, and atmosphere over different hydrological units in mountainous areas such as snow and ice, cold desert, forest and grassland is the basic scientific issue of water research in cold and arid regions, which is also the basis of water resource delicacy management and regulation. There are many research results on the hydrological function of different land covers in mountain areas, basin hydrological processes, however, there are only very limited studies on the water internal recycle at basin scale. The quantitative study on the mechanism of water internal recycle is still at the starting stage, which faces many challenges. The key project “Study on water internal recycle processes and mechanism in typical mountain areas of inland basins, Northwest China” funded by National Natural Science Foundation of China will select the Aksu River and Shule River Basin, which have better observation basis, as study area. The internal mechanism of moisture transfer and exchange process of different land cover and atmosphere, the internal mechanism of water cycle in the basin, and water transfer paths in atmosphere will be studied through enhancing runoff plot experiments on different land cover, analyzing the mechanism of water vapor transfer and exchange between different land covers in the watershed by isotope tracing on the water vapor flux of vegetation water, soil moisture and atmospheric moisture, improving the algorithms of remote sensing inversion and ground verification on land surface evapotranspiration on different land cover, and analyzing the water vapor flux from reanalysis data, and the coupling modeling of regional climate model and land surface process model. At last, the effect of different land cover in hydrological process of mountain area, and the impact of land cover on downstream oasis will be systematically analyzed.  相似文献   

A modified mix-differenced approach for estimating multi-GNSS real-time satellite clock offsets     

Yongchang Chen  Yunbin Yuan  Baocheng Zhang  Teng Liu  Wenwu Ding  Qingsong Ai 《GPS Solutions》2018,22(3):72

A modified mixed-differenced approach for estimating multi-GNSS real-time clock offsets is presented. This approach, as compared to the earlier presented mixed-differenced approach which uses epoch-differenced and undifferenced observations, further adds a satellite-differenced process. The proposed approach, based on real-time orbit products and a mix of epoch-differenced and satellite-differenced observations to estimate only satellite clock offsets and tropospheric zenith wet delays, has fewer estimated parameters than other approaches, and thus its implementing procedure is efficient and can be performed and extended easily. To obtain high accuracy, the approach involves three steps. First, the high-accuracy tropospheric zenith wet delay of each station is estimated using mixed-differenced carrier phase observations. Second, satellite clock offset changes between adjacent epochs are estimated using also mixed-differenced carrier phase observations. Third, the satellite clock offsets at the initial epoch are estimated using satellite-differenced pseudorange observations. Finally, the initial epoch clock results and clock offset changes are concatenated to obtain the clock results of the current epoch. To validate the real-time satellite clock results, multi-GNSS post-processing clock products from IGS ACs were selected for comparison. From the comparison, the standard deviations of the GPS, GLONASS, BeiDou and Galileo systems clock results are approximately 0.1–0.4 ns, except for the BeiDou GEO satellites. The root mean squares are about 0.4–2.3 ns, which are similar to those of other international real-time products. When the clock estimates were assessed based on a pseudo-kinematic PPP procedure, the positioning accuracies in the East, North and Up components reach 5.6, 5.5 and 7.6 cm, respectively, which meet the centimeter level and are comparable to the application of other products.  相似文献   

塔里木盆地塔中志留系柯坪塔格组物源示踪:碎屑锆石U-Pb年代学证据          下载免费PDF全文

李祥权  丁洪坤  彭鹏  吴梅莲  钟楚红  柴雄  刘国威  彭丽 《地球科学》2021,46(8):2819-2831

目前对塔中志留系物源的认识仍存在不确定性.利用LA-ICP-MS分析技术对塔里木盆地塔中地区志留系柯坪塔格组2件样品开展碎屑锆石U-Pb年代学研究.结果表明塔中志留系碎屑锆石主要为岩浆结晶成因,锆石年龄主要分布在早古生代460~490 Ma、新元古代760~1 000 Ma、古元古代1 600~2 200 Ma及新太古代晚期-古元古代早期2 400~2 600 Ma四个时期,其中新元古代760~1 000 Ma碎屑锆石年龄占绝对优势（56.8%）,峰值~850 Ma.结合志留纪时期塔里木板块南北缘的板块动力学背景,通过盆内构造演化及地貌特征的分析以及和潜在源区锆石年龄的详细对比,确定塔中志留系碎屑锆石主要来源于塔里木盆地西南缘的铁克里克隆起构造带.   相似文献   

长江流域地下水资源特征与开发利用现状          下载免费PDF全文

黄长生  周耘  张胜男  王节涛  刘凤梅  龚冲  易秤云  李龙  周宏  魏良帅  潘晓东  邵长生  黎义勇  韩文静  尹志彬  李晓哲 《中国地质》2021,48(4):979-1000

为提升对长江流域水文地质和地下水资源的认知程度,突破以往单独从地表水或地下水角度进行评价的局限性,长江流域水文地质调查工程以地球系统科学理论和水循环理论为指导,充分考虑地表水与地下水的转化关系,将水文地质单元和地表水流域有机结合,划分长江流域地下水评价单元,建立典型地下水资源评价模型,开展了新一轮长江流域地下水资源评价。评价结果表明:(1)长江流域水循环要素时空分布不均,降水以中游最多,并由东南向西北递减;地表径流主要集中在夏季,且长江北岸比南岸集中程度更高;蒸散发量总体上呈现东部高于西部的特征,最大值集中在长江中游一带;长江流域地下水位总体保持稳定,丰枯季水位变化总体不大,一般小于2 m;长三角超采区的地下水漏斗面积已明显减小,相关环境地质问题得到了有效控制。(2)2020年长江流域的地下水资源总量2421.70亿m~3/a,其中山丘区地下水资源量2092.79亿m~3/a,平原区地下水资源量331.35亿m~3/a;地下水储存量较2019年整体略有增加趋势,其中四川盆地最为明显,共增加23.72亿m~3。(3)长江流域的水质上游优于下游,优质地下水主要分布在赣南地区和大别山南麓一带,部分地区水质较差的主要原因是原生劣质水的广泛分布。长江流域地下水开发利用水平整体很低,局部地区由于过往不合理的开发所引发的环境地质问题已得到缓解,岩溶塌陷、地面沉降等问题得到了较好控制。建议适当开发利用赣南地区和大别山南麓一带优质的基岩裂隙水。  相似文献   

Variations of methane stable isotopic values from an Alpine peatland on the eastern Qinghai-Tibetan Plateau     

Guo  Qian  Peng  Haijun  Hong  Bing  Yao  Hu  Zhu  Yongxuan  Ding  Hanwei  An  Ning  Hong  Yetang 《中国地球化学学报》2021,40(4):473-483

Acta Geochimica - Isotopic signature is a powerful tool to discriminate methane (CH4) source types and constrain regional and global scale CH4 budgets. Peatlands on the Qinghai-Tibetan Plateau are...  相似文献   

Fabric evolution and crack propagation in salt during consolidation and cyclic compression tests     

Shen  Xianda  Ding  Jihui  Lordkipanidze  Ilia  Arson  Chloé  Chester  Judith S.  Chester  Frederick M. 《Acta Geotechnica》2021,16(6):1679-1697

  相似文献   

Investigation of the penetration characteristics of snake skin-inspired pile using DEM     

Zhong  Wenhan  Liu  Hanlong  Wang  Qi  Zhang  Wengang  Li  Yongqin  Ding  Xuanming  Chen  Longlong 《Acta Geotechnica》2021,16(6):1849-1865

Acta Geotechnica - Snake can perfectly utilize its scales to move. Inspired by the snake scales, this study investigated the characteristics of the snake skin-inspired pile penetration process. Six...  相似文献   

河南省人工防雹作业指挥系统研发及应用     

鲍向东  丁建芳  杜春丽  刘磊  郭丽梅 《气象与环境科学》2019,42(1):127-134

利用河南省历史气象资料,结合先进的防雹理论与技术,系统分析和总结了河南省冰雹过程的天气尺度与中尺度概念模型,并根据三维冰雹云数值模式及雷达探测、闪电定位、卫星、自动站数据,研发出河南省人工防雹作业指挥系统。该系统包括天气形势分析子系统和作业决策指挥子系统。天气形势分析子系统可根据大尺度形势背景、中尺度系统特征及三维冰雹云数值模式和卫星、闪电、自动站资料,对可能降雹区进行预测。作业决策指挥子系统通过对雷达数据产品的二次开发,完成雷达资料处理、产品生成及风暴自动识别、分类、预警,并根据参数的变化和雹云的移动方向,对下游作业区进行预警及输出作业方案。整个系统基于VS2005开发平台,使用c++开发语言,利用图层分层管理将地理信息、雷达实时观测资料、雷达二次产品、高空资料、火箭和高炮作业点等信息分层显示。系统自动化程度高,操作简便,为河南省冰雹天气预报预警提供了可参考的技术指标体系。  相似文献