Statistical analysis of groundwater chemistry of the Tarim River lower reaches,Northwest China   总被引：2，自引：2，他引：0  

Jianhua Xu  Yaning Chen  Weihong Li  Lijun Zhang  Yulian Hong  Xueli Bi  Yang Yang 《Environmental Earth Sciences》2012,65(6):1807-1820

This study applied a comprehensive quantitative approach including statistical, principal component and gray relation analyses to assess the groundwater chemistry based on monitored data from 840 samples collected from the lower reaches of Tarim River from 2000 to 2009. The main findings were: (1) there were six types of groundwater chemistry in the lower reaches of Tarim River where Cl·SO₄–Na·Mg was the dominant type accounting for 73.57% in all samples. There were linear relationships among chemical parameters, where TDS had significant multiple correlations with Na⁺, K⁺, Mg²⁺, Ca²⁺ and Cl⁻, respectively. (2) Three principal components (PC1, PC2 and PC3) were extracted. They included comprehensive measurements for salinization, alkalinity and pH, respectively. Most parameters showed decreasing trends during the period of 2000–2009, as well as the scores on PC1, because the concentrations of various chemical substances were diluted due to the uplift of the groundwater table in the lower reaches and the implementation of the ecological water delivery project in 2000. (3) HCO₃ ⁻ was the most sensitive chemical parameter affected by the groundwater table followed by TA, Mg²⁺, TH, SO₄²⁻, K⁺, TDS and TS. PC2 was the most sensitive principal component to the change of the groundwater table followed by PC1 and PC3.  相似文献   

基于主波峰的自适应波形重跟踪算法研究     

莫德丽  赵银军  陈国清  梁珊  童凯  梁玉莲 《大地测量与地球动力学》2021,41(10):1051-1056

构建基于主波峰的自适应波形重跟踪算法（AMWRT）。首先提取主波峰,然后对主波峰分别应用经典的重心偏移法（OCOG）及阈值法（threshold）进行波形重跟踪,并进行精度比较,得到最优的观测水位。将AMWRT、OCOG和threshold法应用于长江中游地区,结果表明：1）测高卫星观测的长时间水位序列与水文站实测数据趋势较为一致;2）AMWRT算法相较于OCOG法及threshold法表现良好,比其中表现最好的经典threshold_0.5法的精度提高了30%,其绝对平均误差（MAE）和均方根误差（RMSE）分别降低至0.55 m和0.72 m。  相似文献   

气象档案信息管理系统     

刘玉莲 《黑龙江气象》1999,(3)

１９９７年４月,随着中国气象局第２次《气象档案分类表》的发布,标志着气象档案已与国家档案业务管理标准接轨。气象档案种类繁多、载体形式多样、应用面广,为了便于管理和利用,逐步实现气象档案分类检索体系的规范化,应建立统一的检索咨询网络。《气象档案信息管理系统》课题组于１９９６年末开始,依照《气象档案分类表》规则,编制开发了气象档案数据库目录管理系统。１　系统介绍　　本系统在ＵＣＤＯＳ５０版本平台上用Ｆｏｘｐｌｕｓ＋语言编制开发,全汉字菜单界面,操作简便、直观。１１　数据库设计针对交换资料内容,设…  相似文献