High-pressure study of azurite Cu3(CO3)2(OH)2 by synchrotron radiation X-ray diffraction and Raman spectroscopy     

Jingui Xu  Yunqian Kuang  Bo Zhang  Yonggang Liu  Dawei Fan  Wenge Zhou  Hongsen Xie 《Physics and Chemistry of Minerals》2015,42(10):805-816

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Records of hydrological change and environmental disasters in sediments from deep Lake Issyk-Kul     

Jingzhong Wang  Jinglu Wu  Shuie Zhan  Jianchao Zhou 《水文研究》2021,35(4):e14136

In the context of global warming, the mountainous areas of Central Asia are sensitive to climate and environmental changes and are highly vulnerable to natural disasters. Here, we use high-resolution lacustrine grain-size and geochemical records from Lake Issyk-Kul to infer hydrological changes, environmental events, and their driving factors in the western Tianshan Mountains of Central Asia over the last 350 years. The regional hydrological and environmental changes can be divided into three phases. In stage I (1674–1860 AD), the values of total organic carbon (TOC), total nitrogen (TN) and magnetic susceptibility (MS) were high, and the element contents changed indistinctively, suggesting that lake water levels were relatively stable. In Stage II (1860–2000 AD), the TOC and TN contents increased, the MS values decreased, and the grain size changed markedly, suggesting that water levels fluctuated dramatically. In Stage III (2000–2013 AD), the coarse particle and migratory element contents increased dramatically, indicating that regional rainfall and runoff increased and that the water level rose. Studies have also shown that the synchronous increases in sedimentary coarse particles, TOC and migratory elements indicate multiple flood events. Extreme floods have been frequent and intense in recent years, which indicates that the climate is generally warming, which is in good agreement with tree ring data, ice core records and other sediment records in alpine regions. Additionally, the lake sediments recorded a seismic event in approximately 1910 AD, which was consistent with historical documentation. Comparative analysis of records suggests that the Atlantic Multidecadal Oscillation is one of the dominant factors driving climate and hydrological changes in the study area. Climate change, combined with natural disasters (e.g., earthquakes) and anthropogenic activities, is generating extreme floods and variations in hydrological patterns in the mountain basin. These findings can provide crucial information about sedimentary physicochemical clues for tracking past hydrological and environmental conditions and contribute to a better understanding of hydrological processes and driving factors in the mountainous areas of Central Asia.  相似文献   

土地利用变化对全球气候影响的研究进展与方法初探   总被引：10，自引：0，他引：10  

刘纪远  邵全琴  延晓冬  樊江文  邓祥征  战金艳  高学杰  黄麟  徐新良  胡云峰  王军邦  匡文慧 《地球科学进展》2011,26(10):1015-1022

综合分析了土地利用与土地覆盖变化（LUCC）对全球气候影响研究的重要科学问题和国内外研究现状,在此基础上,考虑各学科的相互交叉、渗透和耦合等特点,提出并初步设计了土地利用变化对全球气候影响研究的星地一体化LUCC—气候—生态系统耦合研究技术方法体系,并就土地利用变化对全球气候影响的LUCC演变规律及动力学机制、LUCC...  相似文献   

再论臼齿碳酸盐岩成因   总被引：4，自引：3，他引：1       下载免费PDF全文

旷红伟  柳永清  彭楠  刘燕学  李家华 《古地理学报》2011,13(3):253-261

臼齿(Molar Tooth,简称MT)碳酸盐岩是产于元古代、并具有特殊全球性意义的碳酸盐岩类型之一.MT特有的微亮晶结构、严格的时空分布范围以及百余年来众多的成因解释,一直吸引着国内外地质学家对其进行持续的研究和探讨.作者在前人研究基础上,基于作者近10余年成果积累及新近对MT微观组构的研究进展,提出了若干新认识.M...  相似文献   

中国城市扩展对气温观测的影响及其高估程度(英文)   总被引：3，自引：1，他引：2  

邵全琴  孙朝阳  刘纪远  何剑锋  匡文慧  陶福禄 《地理学报(英文版)》2011,21(6):994-1006

Since the implementation of the reform and opening up policy in China in the late 1970s, some meteorological stations ’entered’ cities passively due to urban expansion. Changes in the surface and built environment around the stations have influenced observations of air temperature. When the observational data from urban stations are applied in the interpolation of national or regional scale air temperature dataset, they could lead to overestimation of regional air temperature and inaccurate assessment of warming. In this study, the underlying surface surrounding 756 meteorological stations across China was identified based on remote sensing images over a number of time intervals to distinguish the rural stations that ’entered’ into cities. Then, after removing the observational data from these stations which have been influenced by urban expansion, a dataset of background air temperatures was generated by interpolating the observational data from the remaining rural stations. The mean urban heat island effect intensity since 1970 was estimated by comparing the original observational records from urban stations with the background air temperature interpolated. The result shows that urban heat island effect does occur due to urban expansion, with a higher intensity in winter than in other seasons. Then the overestimation of regional air temperature is evaluated by comparing the two kinds of grid datasets of air temperature which are respectively interpolated by all stations’ and rural stations’ observational data. Spatially, the overestimation is relatively higher in eastern China than in the central part of China; however, both areas exhibit a much higher effect than is observed in western China. We concluded that in the last 40 years the mean temperature in China increased by about 1.58℃, of which about 0.01℃ was attributed to urban expansion, with a contribution of up to 0.09℃ in the core areas from the overestimation of air temperature.  相似文献   

石家庄冰雹气候分析及人工防雹布局   总被引：3，自引：0，他引：3  

匡顺四  韩军彩  孙云  刘萍 《气象科技》2013,41(2):407-411

利用石家庄16个县(市)1959-2007年的资料(包括县志),对石家庄冰雹的时空分布特征、冰雹路径等进行了综合分析.分析表明:①石家庄地区降雹日数年变化存在1、11、12和25年的周期性变化,在1971和2003年出现突变;②5月下旬至7月中旬是石家庄降雹盛行季节,一天中降雹多出现在14:00-20:00;③石家庄降雹西部山区多于东部平原,平原上的多雹区一般在河流或古河道附近;④通过资料分析,划分3道人工防雹作业防线,适当增加防雹作业点,科学合理的进行防雹作业点布局,开展阶梯式人工防雹作业.  相似文献   

Erosion Resistance of HPTRM Strengthened Levee from Combined Wave and Surge Overtopping     

Lin Li  Yi Pan  Farshad Amini  Kuang Cuiping  Jean-Louis Briaud 《Geotechnical and Geological Engineering》2014,32(4):847-857

Post-Katrina investigations revealed that most earthen levee damage occurred on the levee crest and land-side slope as a result of either wave overtopping, storm surge overflow, or a combination of both. This study addresses erosion resistance performance of a levee strengthening technique—high performance turf reinforcement mat under combined wave and surge overtopping conditions using full-scale flume tests as well as erosion function apparatus (EFA) tests. Based on the results of full-scale flume tests, an “upper limit” of soil loss is observed for certain flow conditions. Erosion rate was presented as a function of velocity and freeboard. The effect of duration of overtopping on the erosion depth is also determined. The results of EFA tests indicate that the presence of grass roots substantially improve the critical velocity and soil erodibility.  相似文献   

基于潜标观测的牛郎海山的深海海流的低频变化特征     

旷芳芳  张俊鹏  周喜武  陈航宇  靖春生 《海洋学报》2022,44(5):71-79

本文利用在西太平洋牛郎海山布放的两套锚系潜标获取的长时间海流观测数据,分析了深海的海洋动力环境特征,着重阐释了该海域海流的全水深垂向结构及其低频变化特征。结果表明:（1）年平均海流及其变化幅度均在上层最大、中层和深层次之、中深层最小;（2）年平均上,150 m以浅的海流为东向的副热带逆流,150 m以深和中层为西向流;山顶处的近底层海流为较稳定的弱南向流,山底处的近底层海流为西南向流;（3）在山顶和山底,各深度层次的海流在全年均表现出100 d左右的振荡周期;在2 000 m以浅,各深度层次的海流振荡的位相基本一致,振荡幅度在表层最强、随深度的增加而减小;在2 000 m以深,海流变化的位相与2 000 m以浅相反,振荡幅度在4 000 m最强。  相似文献   

Applying a fish expert system for ranking the biological effects of polycyclic aromatic hydrocarbons on the rockfish Sebastiscus marmoratus in the Maowei Sea,China     

Ronghui Zheng  Chao Fang  Fukun Hong  Weiming Kuang  Yulu Jiang  Jincan Chen  Yusheng Zhang  Jun Bo 《海洋学报(英文版)》2022,41(12):105-114

Polycyclic aromatic hydrocarbons (PAHs) pollution, particularly in coastal environments, is a global concern. In this study, the biomonitoring and ranking effects of PAHs in the rockfish Sebastiscus marmoratus were determined in the Maowei Sea, China. The results showed that the concentrations of the 16 priority PAHs detected in the surface seawater were moderate compared with those in other coastal areas worldwide, and the possible sources were rapid industrialization and urbanization combined with atmospheric deposition and runoff. Nested analysis of variance (ANOVA) suggested significant differences in the hepatic ethoxyresorufin-O-deethylase (EROD) activities and phenanthrene-derived metabolites in bile between the port area and the oyster farming area. The fish expert system (FES) was applied to evaluate the biological effects of PAHs on fish. The FES data demonstrated that the biological effect levels of Site S1 (level III, medium stress) were higher than those of the other sampling sites (level II, low stress).  相似文献   

The particle fluxes in sediment traps from Niulang Guyot area in the Northwest Pacific Ocean     

Xiuwu Sun  Jinmin Chen  Baohong Chen  Cai Lin  Yang Liu  Jiang Huang  Zhong Pan  Kaiwen Zhou  Qing He  Fangfang Kuang  Hui Lin 《海洋学报(英文版)》2022,41(11):34-44

The flux of settling particles in the ocean has been widely explored since 1980s due to its important role in biogenic elements cycling, especially in the transport of particulate organic carbon (POC) in the deep sea. However, research in the seamount area of the oligotrophic subtropical Northwest Pacific Ocean is lacking. In this work, two sediment traps were deployed at the foot and another two at the hillside of Niulang Guyot from August 2017 to July 2018. The magnitude and composition of particle fluxes were measured. The main factors influencing the spatial variations of the fluxes were evaluated. Our results indicated a low particulate flux from Niulang Guyot area in the Northwest Pacific Ocean, reflecting low primary productivity of the oligotrophic ocean. The total mass flux (TMF) decreased from 2.57 g/(m2·a) to 0.56 g/(m2·a) with increasing depth from 600 m to 4 850 m. A clear seasonal pattern of TMF was observed, with higher flux in summer than that in winter. The peak flux of 26.52 mg/(m2·d) occurred in August at 600 m, while the lowest value of 0.07 mg/(m2·d) was shown in February at 4 850 m. The settling particles at the deep layers had similar biochemical composition, with calcium carbonate (CaCO₃) accounting for up to 90%, followed by organic matter and opal, characteristics of Carbonate Ocean. The POC flux decreased more rapidly in the twilight layer because of faster decomposition, remineralization, and higher temperature. A small fraction of POC was transported into the deep ocean by biological pump. Particle fluxes were mainly controlled by the calcareous ballasts besides the primary productivity of the surface water. The advection may be another important factor affecting the flux in the seamount area. The combination of settled matters rich in foraminiferal tests with topography and currents may be the reason for regulating the local abundance of benthos on seamounts. Our results will fill in the knowledge gap of sedimentation flux, improve the understanding of ecosystem in Niulang Guyot area, and eventually provide data support for the optimization of regional ecological modeling.  相似文献