多模态地理大数据时空分析方法     

邓敏  蔡建南  杨文涛  唐建波  杨学习  刘启亮  石岩 《地球信息科学学报》2020,22(1):41-56

多模态地理大数据时空分析旨在融合地理大数据的多模态信息发现有价值的时空分布规律、异常表现、关联模式与变化趋势,是全空间信息系统的核心研究内容,并有望成为推进地理学人地关系研究的重要突破口。为应对地理大数据时代的新机遇与挑战,本文围绕4类核心的时空分析方法（时空聚类分析、时空异常分析、时空关联分析与时空预测分析）,系统归纳了国内外研究现状,探讨了时空分析中多尺度建模、多视角协同、多特征认知与多特性表达的研究难点。进而,介绍了多模态地理大数据时空聚类、异常、关联与预测分析模型,更加全面、客观、精准地认知与理解时空大数据中潜在的地理知识,并且能够在气象环境监测、公共安全管理、城市设施规划等多个应用领域发挥关键作用。  相似文献   

Hydrodynamic processes and depositional styles of glacier-associated deposits in the Moxi basin,Southwest China     

Yong-bo Tie  Xing-lei Feng  Jing Ran  Wei Xu 《山地科学学报》2016,13(3):557-568

This study aims to understand the particle size distribution and depositional styles of glacier-associated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated deposits (including glacial till, fluvioglacial, debris flow, river and lake deposits) were collected and tested in the laboratory. The results showed that the glacier-associated deposits can be differentiated based on particle gradation, particle size distribution and accumulated percentages. We evaluated the evolution of a former dammed lake in the Moxi basin based on glacier-associated deposits. The results of this study also indicated that the Moxi Platform was not formed by a single depositional process but is composed of both fluvioglacial and debris flow deposits. This research shows that the depositional style analysis is useful in identifying different glacier-associated deposits in high mountain regions. Moreover, the evaluation of the differences in particle sizes of the glacierassociated deposits is useful in reconstructing geohazard events in periglacial regions, and this information can help in identifying and reducing the potential risks associated with geo-hazards.  相似文献   

Optical properties of cirrus transition zones over China detected by CALIOP          下载免费PDF全文

Hongke Cai  Yunfei Fu  Quanliang Chen  Xiao Feng  Xin Tie  Ranting Tao  Kepiao Xu 《Acta Meteorologica Sinica》2017,31(3):576-585

A transition zone near cirrus lateral boundaries can be detected by CALIOP (cloud–aerosol lidar with orthogonal polarization). In the present study, for such transition zones over China, a number of optical properties, such as the backscatter coefficient and depolarization ratio, showed transitional characteristics between cirrus and clear sky. The stepped horizontal profile showed sharp changes in particle number and morphology between cirrus clouds and clear sky. The color ratio, however, was unable to show cirrus transition features because of the low signal-to-noise ratio. Typical ice particles presented a color ratio of 0.55–1.25 and a depolarization ratio of greater than 0.12, which were significantly higher than those of clear sky. Therefore, optical properties in transition took the form of stepwise horizontal profiles. The proportion of typical-featured particles also demonstrated a stepped horizontal profile similar to the optical characteristics, but the relationship between the proportion and the optical characteristics was not uniform in the cirrus clouds, transition zone, and clear sky. Therefore, the optical changes in the transition zone were caused by not only the change in particle concentration, but also the change in the particles themselves. The probability density distribution of the transition-zone widths showed a positive skewness distribution, and transition zones with widths of 3–5 km occurred most frequently. Overall, transition-zone width decreased with increasing temperature and increased with increasing vertical and horizontal wind speeds. This trend demonstrated independence with the direction of the vertical and horizontal winds. These observations implied that the transitional features were caused by material exchange, such as entrainment and turbulent transport, near the cirrus lateral boundaries, and by the phase transformation of particles, such as sublimation.  相似文献   

浅海原油净化过程的模拟实验──分散油的挥发降解过程   总被引：2，自引：0，他引：2  

王永辰  祝陈坚  孙秉一  史致丽  于圣睿  郝恩良  李铁  石晓勇 《海洋与湖沼》1995,26(4):389-396

于1989年3－7月在青岛海洋大学进行“河口”原油和“东营”原油实验室模拟实验，以了解海上溢油进入海水中的分散（溶解和乳化）油的挥发降解过程。结果表明，分散油的蒸发速率除与原油本身性质有关外，还与环境温度、水体盐度和水面风速有关。水体中油含量随时间变化可表示为：，温度、盐度和风速增大时，均有助于分散油的挥发，其中风速变化对Kv的影响最大，而盐度变化的影响最小。  相似文献   

合成孔径雷达反演黄海海面风场   总被引：1，自引：0，他引：1  

王铁 《海洋湖沼通报》2007,91(4):10-13

基于后向散射系数反演高空间分辨率海面风场,采用谱方法确定风向,并利用CMOD4模式函数反演风速。以ERS-2 SAR黄海区域图像为例,反演海面风场,并将反演结果同QuikSCAT散射计对比,比较吻合,证明该方法在黄海区域的可行性。  相似文献   

Palaeoceanological significance of Holocene ostracean banks in Tianjin area     

Wang Qiang  Li Xiuwen  Zhang Zhiliang  Li Fenglin  Shao Jun  Bai Dezhong  Shang Xuexi  Tang Ruolu 《海洋学报(英文版)》1991,10(2):249-262

On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.  相似文献   

Physiological responses of macroalga Gracilaria lemaneiformis (Rhodophyta) to UV-B radiation exposure     

朱琳  肖慧  王影  菅潇扬  张智鹏  张焕新  唐学玺 《中国海洋湖沼学报》2015,33(2):389-399

This paper aims to evaluate the effects of ultraviolet-Bradiation(UVBR) on Gracilaria lemaneiformis,a commercial red macroalga and an important source of agar. To study the in-vitro effect of UVBR on G. lemaneiformis,this plant was cultivated and exposed to photosynthetically active radiation(PAR) at 40 μmol photons/(m2 ·s) and enhanced UVBR(0,0.36,0.72,1.08,1.44,and 1.80 k J/(m 2 ·d)) for 13 days. The samples were processed for histochemical analysis,and the growth rate,photosynthetic pigment contents,photosynthetic performance,reactive oxygen species levels,membrane permeability,malonyl dialdehyde contents and antioxidant capacity of G. lemaneiformis were investigated. After 13 days of exposure to PAR+UVBR,G. lemaneiformis showed photodamage and photoinhibition of photosynthetic pigments(chlorophylla and phycoerythrin),leading to a decreased photosynthetic efficiency. Further,there was a corresponding decrease in the relative growth rates and depigmentation and partial necrosis of the apical segments were noted after exposure to PAR+UVBR. Additionally,UVBR induced excess production of superoxide radicals and hydrogen peroxide,eliciting a marked cellular membrane damage and antioxidative response.  相似文献   

Effects of different light conditions on repair of UV-B-induced damage in carpospores of Chondrus ocellatus Holm     

鞠青  肖慧  王悠  唐学玺 《中国海洋湖沼学报》2015,33(3):664-678

We evaluated the effects of ultraviolet-B(UV-B) radiation and different light conditions on the repair of UV-B-induced damage in carpospores of C hondrus ocellatus Holm(Rhodophyta) in laboratory experiments. Carpospores were treated daily with different doses of UV-B radiation for 48 days,when vertical branches had formed in all treatments; after each daily treatment,the carpospores were subjected to photosynthetically active radiation(PAR),darkness,red light,or blue light during a 2-h repair stage. Carpospore diameters were measured every 4 days. We measured the growth and cellular contents of cyclobutane pyrimidine dimers(CPDs),chlorophyll a,phycoerythrin,and UV-B-absorbing mycosporine-like amino acids(MAAs) in carpospores on Day 48. Low doses of UV-B radiation(36 and 72 J/m 2) accelerated the growth of C. ocellatus. However,as the amount of UV-B radiation increased,the growth rate decreased and morphological changes occurred. UV-B radiation significant damaged DNA and photosynthetic pigments and induced three kind of MAAs,palythine,asterina-330,and shinorine. PAR conditions were best for repairing UV-B-induced damage. Darkness promoted the activity of the DNA darkrepair mechanism. Red light enhanced phycoerythrin synthesis but inhibited light repair of DNA. Although blue light,increased the activity of DNA photolyase,greatly improving remediation efficiency,the growth and development of C. ocellatus carpospores were slower than in other light treatments.  相似文献   

The toxic effects of copper on larvae of the barnacle species Chthamalus challengeri     

齐磊磊  王影  沙婧婧  王悠  唐学玺 《中国海洋湖沼学报》2015,33(2):400-409

With the increased use of copper(Cu)-based antifouling(AF) paints,copper has become a potential threat to marine organisms. Experiments were performed to investigate the effects of copper on larvae of the barnacle Chthamalus challengeri. These experiments attempted to identify a more sensitive index to monitor copper pollution in marine environments. The 24 h LC5 0 ranged from 156.07 μg/L(nauplius II) to 817.15 μg/L(cypris) and the no observed effect concentration(NOEC) ranged from 81.75 μg/L(nauplius II) to 571.04 μg/L(cypris). The cypris settlement rate declined significantly when copper concentrations ≥135 μg/L. No cypris was found in the copper concentration of 60 and 75 μg/L treatment groups stressed for 22 d. Nauplius II moulting was not affected by exposure to copper for 24 h; however,when extended to 48 h,the percent moulted in 75 μg/L treatment group was declined to 37.12%,which was significant lower( P 0.05) than that in the control group. The phototaxis of nauplius II decreased significantly when copper concentrations ≥45 μg/L. Despite an initial significant increase at copper concentrations of 30 μg/L,ammonia excretion rate decreased when copper concentrations ≥60 μg/L. These results suggested that:(1) nauplius II could not develop to the cypris when the copper concentration ≥60 μg/L;(2) cypris settlement is more susceptible to copper than cypris mortality rate;(3) nauplius II is the most sensitive larval stage;(4) nauplius II ammonia excretion rate is the most sensitive index to copper and might be as the indicator for copper pollution monitoring.  相似文献   

地下水位变化对金州水准基岩标石的影响分析     

尚贵佳  王铁  李宝君  于治信 《防灾减灾学报》2021,37(2):39-44

对辽宁金州地震台地下水位上升引起水准基岩标石底部岩层的应力变化进行定性和定量分析,并使用分层总和法计算基岩标石受到的影响量.研究结果表明,金州水准所受地下水的干扰,主要是标石底部的基岩在地下水位变化的作用下而发生形变所致,其影响的大小与水位变化幅度、水容重、基岩的压缩模量和孔隙度有关.  相似文献