Potential of Detecting the Sulfur Dioxide Stress on Landscape Plants in Spectral Reflectance Data     

Di Wang  Ziqi Liu  Yuanyong Dian  Zhixiang Zhou  Shenghui Fang 《Journal of the Indian Society of Remote Sensing》2018,46(4):561-568

Sulfur dioxide (SO₂) exhibits a powerful implication on the air condition and responsible for increasing the acidity of rainfall which plays negative effects on plant growth. It is a big problem to quantitatively access the stress degrees of sulfur dioxide on landscape plants. This study aims to find a non-destructive way to detect the degrees of SO₂ stress by using the spectral reflectance data. Five different landscape plants were selected and a simulated SO₂ stress environment by using fumigation box was built in this experiment. Landscape plants were grown on at this simulated SO₂ environment, and the leaf reflectance, chlorophyll and sulfur concentration were measured at 0, 2, 4, 6, 8, 10 and 12 h respectively. The spectral, chlorophyll response of five different plants were examined and the red edge position (REP) shift obtained from the reflectance were used to evaluate the SO₂ stress degrees at this paper. The results showed leaf chlorophyll content generally decreased and leaf sulfur content generally increased of all of these five landscape plants as though the chlorophyll and sulfur content disturbing during the whole stress time. However, compared with the sulfur content changed in leaves, chlorophyll content did not significantly changed when suffering from SO₂. The shift of REP performed well to indicate the severity of SO₂ fumigation stress and different species showed the different REP shift. The determined coefficient R² of REP shift and the relative changed sulfur content in leaves can up to 0.85. And the results also indicated that the different species maintained different resistance to SO₂.  相似文献   

锆石微量元素对成矿岩体的判别——来自大数据思维的应用     

耿厅  周永章  李兴远  王俊  陈川  王堃屹  韩紫奇 《地质通报》2019,38(12):1992-1998

华南钦杭结合带燕山期岩浆活动异常活跃,且具有较明显的成矿专属性。近年来微区测试技术日益成熟,积累了大量锆石微量数据。通过全体数据挖掘的思维方法,对前人发表的数据进行了进一步数据挖掘,利用锆石稀土元素对岩体成矿潜力进行判别,探讨有效的找矿地球化学标志。利用Python语言编程,对采用的13种稀土元素及元素比值进行穷举式组合,获得了4095个二元图解及121485个三元图解,并设计筛选算法,自动筛选出能有效区分锆石母岩成矿类型的图解。结果表明,锆石稀土元素含量及比值图解对不同成矿类型岩体的区分程度各异:与Ce、Eu有关的地球化学指标可以较清晰地对斑岩铜矿和钨锡(锡)矿床进行判别,这可能与岩体的氧逸度和含水量有关。此外,还挖掘出一些新的元素组合图解,如Dy/Lu-Er/Lu、Gd/Dy-Er/Yb等,可以有效区分岩体成矿类型,其隐含的地球化学机制尚待进一步解释。地球化学数据挖掘结果可以作为找矿标志使用,为华南燕山期岩浆-热液矿床研究及找矿勘查提供了科学依据,也是大数据技术在矿床学方面应用研究的积极探索。  相似文献   

Fracture Development at Laminated Floor Layers Under Longwall Face in Deep Coal Mining     

Li  Chunyuan  Zuo  Jianping  Wei  Chunchen  Xu  Xiang  Zhou  Ziqi  Li  Yang  Zhang  Yong 《Natural Resources Research》2020,29(6):3857-3871

Natural Resources Research - The increment of stress level and fracture depth in deep longwall mining can cause groundwater inrush accidents frequently, and it is essential to study the...  相似文献   

Computational improvements to multi-scale geographically weighted regression     

Ziqi Li  A. Stewart Fotheringham 《International journal of geographical information science》2020,34(7):1378-1397

ABSTRACT

Geographically Weighted Regression (GWR) has been broadly used in various fields to model spatially non-stationary relationships. Multi-scale Geographically Weighted Regression (MGWR) is a recent advancement to the classic GWR model. MGWR is superior in capturing multi-scale processes over the traditional single-scale GWR model by using different bandwidths for each covariate. However, the multiscale property of MGWR brings additional computation costs. The calibration process of MGWR involves iterative back-fitting under the additive model (AM) framework. Currently, MGWR can only be applied on small datasets within a tolerable time and is prohibitively time-consuming to run with moderately large datasets (greater than 5,000 observations). In this paper, we propose a parallel implementation that has crucial computational improvements to the MGWR calibration. This improved computational method reduces both memory footprint and runtime to allow MGWR modelling to be applied to moderate-to-large datasets (up to 100,000 observations). These improvements are integrated into the mgwr python package and the MGWR 2.0 software, both of which are freely available to download.  相似文献   

土壤湿度遥感估算同化研究综述   总被引：5，自引：0，他引：5  

Lan Xinyu  Guo Ziqi  Tian Ye  Lei Xia  Wang Jie 《地球科学进展》2015,30(6):668-679

土壤湿度是影响气候的至关重要的变量之一。利用数据同化方法反演大规模高精度土壤湿度数据是目前土壤水分研究的一个重要方向。结合国内外土壤湿度遥感估算研究现状,总结了土壤水分同化算法主要应用进程,梳理了目前实现土壤水分反演且应用广泛的陆面过程模型,Noah模型、通用陆面过程模型CLM、简单生物圈模型Si B2、北方生产力模拟模型BEPS,介绍了大范围卫星土壤水分数据集,包括陆面同化系统数据集、ASCAT数据集、AMSR-E数据集及SMOS数据集,最后探讨了遥感土壤水分同化过程中存在的问题及发展方向。  相似文献   

Compensation of SQUID gradient data in a magnetic tensor gradiometer system for airborne exploration     

Shuangxi Ji  Huai Zhang  Ziqi Guo 《《地质学报》英文版》2018,92(Z1):326-327

  相似文献   

川南宁西地区龙一段高密度甲烷包裹体发育特征及地质意义          下载免费PDF全文

柳卓  郝芳  刘鑫  吴伟  全力  田金强  冯子齐 《地球科学》2021,46(9):3157-3171

作为川南志留系页岩气重点拓展区,宁西地区经历多次断裂活动,龙一段普遍发育方解石脉体,同时由于热演化程度极高,出现石墨化现象,致使页岩气富集规律不明.本次研究以区内重点探井——宁西202井的龙一段为研究对象,通过系统岩心描述、薄片镜下观察、阴极发光、激光拉曼光谱和显微测温等实验分析,进行了古温压恢复研究.研究表明:龙一段主体分布高角度方解石脉体（A类）,局部发育顺层脉体（B类）.A类脉体中主要发育高密度甲烷包裹体、部分样品出现特殊的沥青包裹体.沥青包裹体中沥青的拉曼R_o（_RmcR_o）为3.52%~4.16%,处于过成熟至石墨化阶段.甲烷拉曼散射峰介于2 910.711 2~2 912.495 1 cm—1,均一温度介于-99.8~-96.3℃.通过拉曼参数位移法和显微测温法分析得出的密度值分别介于0.253 6~0.344 5 g/cm3和0.291 6~0.303 2 g/cm3,呈典型的高密度特征.综上,高密度甲烷包裹体可能捕获于燕山构造运动抬升初期,处于超压状态,指示页岩系统封闭性较好,有利于页岩气的富集.   相似文献   

Human activity and climate change triggered the expansion of rocky desertification in the karst areas of Southwestern China     

Chen  Chaojun  Yuan  Daoxian  Cheng  Hai  Yu  Tsailuen  Shen  Chuanchou  Edwards  R. Lawrence  Wu  Yao  Xiao  Siya  Zhang  Jian  Wang  Tao  Huang  Ran  Liu  Ziqi  Li  Tingyong  Li  Junyun 《中国科学:地球科学(英文版)》2021,64(10):1761-1773

It is conducive to the sustainable development of human beings in karst regions to research the mechanism of karst rocky desertification(KRD) expansion. Whether the large-scale KRD in southwestern China is caused by climate change or human activities is still controversial. In this study, the evolution of the KRD in southwestern China over the past 2000 years was reconstructed through the high-precision δ~(13) C record of stalagmites from Shijiangjun(SJJ) Cave, Guizhou Province, China. Theδ~(13) C of the stalagmites from SJJ Cave exhibited heavy values from the Medieval Warm Period(MWP) to the Little Ice Age(LIA). Furthermore, the δ~(13) C records of other stalagmites and tufa from southwestern China also showed the same significant heavy trend. Because the stalagmite δ~(13) C could record the change of ecological environment, it indicated that the consistent change of the stalagmites δ~(13) C may record the process of KRD expansion in the karst regions of southwestern China. During the MWP, the stronger Asian summer monsoon and the northward movement of the rain belt led to a dry period in southwestern China and a wet period in northern China. In contrast, it was wet in southwestern China and dry in northern China during the LIA.In addition, after the Jing-Kang event(JK event, AD1127) occurred at the end of the Northern Song dynasty, the political and economic center of China migrated to southern China for the first time, which changed the population distribution pattern of larger population in the north and smaller population in the south. Therefore, the expansion of KRD in southwestern China was exacerbated in the MWP due to the change of climate in southwestern China, the migration of a large number of people, wars, the large-scale reclamation of arable land, and the cultivation of large areas of crops.  相似文献   

气象要素对中国大气能见度长期变化影响的定量研究     

刘骞  盛立芳  王园香  曹子淇  屈文军 《气候与环境研究》2016,21(1):47-55

近30年中国大气能见度整体呈下降趋势,其中东部地区尤为明显,为揭示复杂气象因素对能见度长期变化的影响,利用1980~2012年中国521站地面气象观测资料,建立了气象要素与能见度之间的多元非线性回归关系。结果表明:相对湿度、风速和气温这3种气象要素对能见度的平均解释方差为22%;其中有68个站点通过了显著性检验(显著性水平α=0.05),平均解释方差达到55%。这些站点中,相对湿度影响显著的站点主要集中在东南沿海,风速影响显著的站点分布在除新疆以外的中国大部,而气温影响显著的站点主要位于中国中部的带状区域。3种气象要素对能见度的影响存在着时间尺度上的不同,相对湿度和气温对能见度的影响主要体现在线性趋势方面,而风速对能见度长期变化的影响主要体现在年代际变化方面。中国东部地区能见度长期下降趋势主要受70%以上相对湿度减少趋势和4 m/s以下风速年代际变化的影响。  相似文献   

灰色系统理论在油气储层精细评价解释中的应用——以福山凹陷下第三系储层为例     

谭成仟  宋子齐  李喜安 《海相油气地质》2001,6(1):42-46

依据福山凹陷下第三系碎屑岩储层中具有代表性的岩心、测井和地质资料,利用灰色系统测井地质综合评价分析准则和自动处理方法,建立该凹陷的评价解释参数、标准、权系数及自动分析解释系统,对该凹陷40多口井主要目的层段储层进行了精细评价处理,获得了较为可靠的储层描述和测井解释,准确划分出一、二、三、四类油气储层。以两口井的解释实例阐述了福山凹陷金凤构造油气藏特点及分布,揭示出该构造区油气显示广泛,成油条件有利,从而较为准确地描述了该区下第三系砂岩储层的结构、特征及产能,为进一步勘探开发提供了相应的地质依据。  相似文献