柴达木盆地西北部长垄状雅丹沉积物地球化学元素组成及指示意义   总被引：2，自引：2，他引：0  

郜学敏  屈欣  王萌  张思悦  张姚姚  李继彦 《中国沙漠》2021,41(3):127-136

雅丹沉积物蕴含丰富的区域环境变化和物源演变信息。以柴达木盆地西北部的长垄状雅丹为研究对象,通过对地球化学元素的研究,探讨沉积物的化学风化特征及其对物质输移的指示意义。结果表明：（1）雅丹沉积物的常量元素以SiO₂、CaO、Al₂O₃、MgO和Na₂O为主,微量元素Cl、Sr、Ba和Zr含量较高。相较于上陆壳平均化学元素组成,雅丹沉积物常量元素CaO和MgO富集程度较高,微量元素中Cl和As富集程度较高。（2）雅丹沉积物的CIA值平均为39.03,且在A-CN-K三角图上准平行于A-CN连线,主体在斜长石与钾长石连线的下方,因此雅丹沉积物的化学风化程度较低,处于初期的脱Na、Ca阶段。（3）特征元素比值表明雅丹体内赋存的大量细颗粒物质为廊道流沙的源区。细颗粒物质经过外营力的风化、剥蚀等过程而出露,在雅丹廊道内堆积并向下风向输移,遇阻堆积而形成沙丘。雅丹是否为下风向黄土的物源区,尚需进一步验证。  相似文献   

广州长租公寓租赁意向的影响机制——基于计划行为理论的扎根研究     

杨高  刘柳颖  周春山 《热带地理》2021,41(3):562-572

对21位有过广州长租公寓租赁经历的租客进行深度访谈,运用扎根理论研究方法对访谈资料进行逐级编码,基于计划行为理论分析框架构建了广州长租公寓租赁意向影响机制模型。研究表明：租客在长租公寓租赁过程中,其租赁行为会受到租赁意向的驱动,租赁意向受到租赁态度、主观规范、知觉行为控制的共同影响。租赁态度由住房情感需求、住房品牌偏好、住房功能需求产生的内生态度和租赁住房产生的风险判断、附加利益等外生态度共同构成;主观规范包括指令性规范和示范性规范,他人期待、住房租赁政策认知、社交媒体引导是指令性规范的重要组成部分,示范性规范主要指他人租赁;知觉行为控制则由自我效能和便利条件构成。  相似文献   

The Potential Vertical Distribution of Bigeye Tuna ( Thunnus obesus ) and Its Influence on the Spatial Distribution of CPUEs in the Tropical Atlantic Ocean     

Shenglong Yang  Liming Song  Yu Zhang  Wei Fan  Bianbian Zhang  Yang Dai  Heng Zhang  Shengmao Zhang  Yumei Wu 《中国海洋大学学报(英文版)》2020,19(3):669-680

Understanding the potential vertical distribution of bigeye tuna(Thunnus obesus) is necessary to understand the catch rate fluctuations and the stock assessment of bigeye tuna. To characterize the potential vertical distribution of this fish while foraging and determine the influences of the distribution on longline efficiency in the tropical Atlantic Ocean, the catch per unit effort(CPUE) data were compiled from the International Commission for the Conservation of Atlantic Tunas and the Argo buoy data were downloaded from the Argo data center. The raw Argo buoy data were processed by data mining methods. The CPUE was standardized by support vector machine before analysis. We assumed the depths with the upper and lower limits of the optimum water temperatures of 15℃ and 9℃ as the preferred swimming depth, while the lower limit of the temperature(12℃) associated with the highest hooking rate as the preferred foraging depth(D12) of bigeye tuna during the daytime in the Atlantic Ocean. The preferred swimming depth and foraging depth range in the daytime were assessed by plotting the isobath based on Argo buoy data. The preferred swimming depth and vertical structure of the water column were identified to investigate the spatial effects on the CPUE by using a generalized additive model(GAM). The empirical cumulative distribution function was used to assess the relationship between the spatial distribution of CPUE and the depth of 12℃ isolines and thermocline. The results indicate that 1) the preferred swimming depth of bigeye tuna in the tropical Atlantic is from 100 m to 400 m and displays spatial variation; 2) the preferred foraging depth of bigeye tuna is between 190 and 300 m and below the thermocline; 3) the number of CPUEs peaks at a relative depth of 30 –50 m(difference between the 12℃ isolines and the lower boundary of the thermocline); and 4) most CPUEs are within the lower depth boundary of the thermocline levels(LDBT) which is from 160 m to 230 m. GAM analysis indicates that the general relationship between the nominal CPUE and LDBT is characterized by a dome shape and peaks at approximately 190 m. The oceanographic features influence the habitat of tropical pelagic fish and fisheries. Argo buoy data can be an important tool to describe the habitat of oceanic fish. Our results provide new insights into how oceanographic features influence the habitat of tropical pelagic fish and fisheries and how fisheries exploit these fish using a new tool(Argo profile data).  相似文献   

高亚洲及其邻区2003~2017年质量平衡的气候影响分析     

汪汉胜  张会同  相龙伟  江利明  沈强  STEFFEN Holger 《大地测量与地球动力学》2020,40(12):1211-1218

利用重力恢复和气候实验(GRACE)数据获得高亚洲及其邻近地区的质量变化,可分析区域气候因素如印度季风、西风带和厄尔尼诺-南方涛动(ENSO)对结果的影响。然而,最近的研究发现,西风带的贡献小于厄尔尼诺,与传统研究结论不同。因此,利用2003-01~2017-06期间GRACE RL06的Mascon数据进行复经验正交函数（CEOF）分析。研究发现,前3个主要成分对研究区质量变化的贡献率分别为53%、27%和6%,与印度季风、西风带和ENSO指数的相关系数分别是0.92±0.16、0.70±0.15和0.42±0.15,说明在长达14 a的观测时间跨度内,印度季风、西风带和ENSO对研究区质量变化的贡献分别为53%、27%和6%,西风带是研究区质量变化的第2个影响因素,这支持了传统的研究结论;ENSO通过印度季风对某些区域（如帕米尔高原、喜马拉雅山脉和印度西北部）的质量变化产生影响;在印度西北部、喜马拉雅山脉和藏东南地区,由于印度季风的减弱及其相关的ENSO作用和西风带的加强,质量变化呈现下降趋势;在兴都库什、西昆仑和东昆仑地区,由于西风带的增强,质量变化呈上升的趋势;在帕米尔和天山地区,虽然受到较强西风带的影响,但由于同时受到印度季风和ENSO减弱以及气温上升趋势的影响,质量变化呈下降的趋势。  相似文献   

Provenance and Tectonic Implications of Paleozoic Strata in the South Yellow Sea Basin,China–Revealed from the Borehole CSDP-2     

Gao  Xiaohui  Zhang  Xunhua  Guo  Xingwei  Cai  Laixing  Hou  Fanghui  Zhu  Xiaoqing 《中国海洋大学学报(英文版)》2020,19(3):536-550

Well CSDP-2 is a fully coring deep drilling hole, penetrating the thick Paleozoic marine strata in the South Yellow Sea Basin(SYSB) in the lower Yangtze Block(LYB). Based on the petrological and geochemical analysis of 40 sandstone samples from the core CSDP-2, the provenance and tectonic features of Paleozoic detrital rocks from SYSB are analyzed and systematically delineated in this article. The results show that the Silurian – Carboniferous sandstones are mature sublitharenite, while the Permian sandstones are unstable feldspathic litharenite. The average CIA(chemical index of alteration) is 74.61, which reflects these sediments were derived from source rocks with moderate chemical weathering. The REE(rare earth element) patterns are characterized by LREE enrichment, flat HREE and obviously negative Eu anomaly, which are similar to that of the upper continental crust. Dickinson QFL discrimination results indicate the recycled orogeny provenance. Various diagrams for the discrimination of sedimentary provenance based on major and trace element data show all the sediments were derived predominantly from quartz sedimentary rocks, of which the Permian strata contain more felsic sedimentary rocks. Geochemical data for these detrital rocks suggest they occur at the passive continental margin and island arc settings, and the Permian sandstone presents active continental margin setting.  相似文献   

Transcriptomic Profiling of the Immune Response to Crowding Stress in Juvenile Turbot (Scophthalmus maximus)     

Huo  Huanhuan  Gao  Xiaoqiang  Fei  Fan  Qin  Fei  Huang  Bin  Liu  Baoliang 《中国海洋大学学报(英文版)》2020,19(4):911-922

  相似文献   

一种基于分布中心的矢量数据零水印算法     

吕文清  张黎明 《测绘工程》2017,26(8)

针对鲜有零水印算法能同时适用于点、线、面矢量数据版权保护,提出一种基于分布中心的矢量地理空间数据零水印算法。首先,对矢量数据进行格网划分;其次,计算格网内每个点到其算数平均值中心的距离,并将得到的距离序列与距离平均值进行比较,大于等于距离平均值,则记为1,否则为0;然后,统计格网内的0和1数量的多数,记为0或1,以此生成空间数据特征值;最后,将该特征值与置乱后的二值水印进行异或,构造出零水印图像。实验表明,文中算法能同时适用于点、线、面矢量数据,并且对常见的平移、缩放、裁剪、格式转换、随机删点等攻击鲁棒性好。  相似文献   

Ionospheric and receiver DCB-constrained multi-GNSS single-frequency PPP integrated with MEMS inertial measurements     

Zhouzheng Gao  Wenbin Shen  Hongping Zhang  Xiaoji Niu 《Journal of Geodesy》2017,91(11):1351-1366

Single-frequency precise point positioning (SF-PPP) is a potential precise positioning technique due to the advantages of the high accuracy in positioning after convergence and the low cost in operation. However, there are still challenges limiting its applications at present, such as the long convergence time, the low reliability, and the poor satellite availability and continuity in kinematic applications. In recent years, the achievements in the dual-frequency PPP have confirmed that its performance can be significantly enhanced by employing the slant ionospheric delay and receiver differential code bias (DCB) constraint model, and the multi-constellation Global Navigation Satellite Systems (GNSS) data. Accordingly, we introduce the slant ionospheric delay and receiver DCB constraint model, and the multi-GNSS data in SF-PPP modular together. In order to further overcome the drawbacks of SF-PPP in terms of reliability, continuity, and accuracy in the signal easily blocking environments, the inertial measurements are also adopted in this paper. Finally, we form a new approach to tightly integrate the multi-GNSS single-frequency observations and inertial measurements together to ameliorate the performance of the ionospheric delay and receiver DCB-constrained SF-PPP. In such model, the inter-system bias between each two GNSS systems, the inter-frequency bias between each two GLONASS frequencies, the hardware errors of the inertial sensors, the slant ionospheric delays of each user-satellite pair, and the receiver DCB are estimated together with other parameters in a unique Kalman filter. To demonstrate its performance, the multi-GNSS and low-cost inertial data from a land-borne experiment are analyzed. The results indicate that visible positioning improvements in terms of accuracy, continuity, and reliability can be achieved in both open-sky and complex conditions while using the proposed model in this study compared to the conventional GPS SF-PPP.  相似文献   

辽宁省潜在蒸散发量及其敏感性规律分析   总被引：2，自引：0，他引：2  

曹永强  高璐  袁立婷  李维佳 《地理科学》2017,37(9):1422-1429

采用Penman-Monteith法和敏感系数法对辽宁省1965~2014年潜在蒸散发量及影响潜在蒸散发的气象因子敏感性进行分析,探讨气候变化下影响辽宁省潜在蒸散发量变化的主导因子及潜在蒸散发对气候变化的定量响应。结果表明：① 近50 a辽宁省潜在蒸散发呈现显著减少趋势,在空间上由西向东递减;② 潜在蒸散发对气象因子的敏感性在年尺度上表现为,水汽压最为敏感,其次为太阳辐射、风速、平均气温;在季节尺度上,春季和秋季对平均气温最不敏感,夏季对风速最不敏感,冬季对太阳辐射最不敏感;③ 空间分布上,气象因素的敏感系数与气象因子空间变化规律相吻合,潜在蒸散发对气温的敏感性由北部向南部递增,对水汽压、太阳辐射的敏感性由东部向西部递减,而风速与之变化趋势相反。④ 风速的显著降低是辽宁省潜在蒸散发量下降的主要原因,太阳辐射的下降及水汽压的升高也促使了潜在蒸散发量的下降。  相似文献   

河南“米”字形高铁网构建对可达性及城市空间格局影响   总被引：4，自引：4，他引：0  

孟德友  魏凌  樊新生  高超 《地理科学》2017,37(6):850-858

从可达性的视角采用平均旅行时间、经济潜力、日常可达性等指标对河南“米”字形高速铁路网构建对各地市省内和省际可达性及城市空间格局的影响进行分析发现,① “米”字形高速铁路网有助于各地市省内和省际可达性水平提升,郑州的极化与集聚效应进一步增强,边界城市的交通边缘化状况明显改善,“米”字形城镇发展轴带正在形成;② 各地市省内和省际经济潜力大幅度提升,位置居中的高铁沿线城市省内区位优势显著,边界高铁沿线城市在省际联系中的门户区位优势显现;③ 以郑州中心的0.5 h核心圈、1 h紧密圈正在形成,“同城效应”显现,各地市省际2 h交流圈大幅度拓展,以郑州为中心的1.5 h省际合作圈即将形成。高铁网的构建将成为河南城市空间格局演变的重要推动因素和空间结构优化的基础支撑条件。  相似文献