千岛湖流域水质变化与经济发展耦合协调性分析   总被引：1，自引：1，他引：0  

张姗姗  张落成  李刚  李昌峰  吴志旭 《湖泊科学》2014,26(6):948-954

利用主成分分析和相关分析相结合的方法,建立水环境质量和经济发展的协调度模型,对千岛湖流域水环境与经济发展趋势及协调度变化趋势进行分析.结果表明,2000年以来千岛湖流域水环境质量与经济发展协调状况经历了从濒临失调向轻度失调再到趋近协调的转变过程:以5年为滑动周期考察协调度的演变趋势发现,2000-2012年千岛湖流域协调度大致呈"V"型趋势,2000-2004年水环境质量略有下降,经济发展缓慢,2004-2008年由于经济迅猛发展、水环境质量迅速下降,水质与经济发展处于失调状态,经过2008年转折点后,水环境质量开始改善,2008-2012年协调度达最高点,处于趋近协调,开始向初级协调状态转变.  相似文献   

Preface to the Special Issue on Earthquake-Induced Landslides     

XU Chong  JIANG Yuanjun  LIU Chun  LU Heng 《中国地震研究》2020,34(1):1-4

正Earthquake-induced landslides are the most destructive secondary geological hazards following large earthquakes that can destroy infrastructures and cause loss of lives and properties (Marano K.D.et al.,2010;Xu Chong et al.,2018).In the past few decades,earthquake-induced landslides have captured growing interests of both scientific communities  相似文献   

洋中脊扩张速率对洋壳速度结构的约束          下载免费PDF全文

李龑  牛雄伟  阮爱国  刘绍文  Syed Waseem Haider  卫小冬 《地球物理学报》2020,63(5):1913-1926

洋中脊速度结构是揭示大洋岩石圈演化过程的重要约束.为探讨不同扩张速率下洋中脊的洋壳速度结构特征,挑选了全球152处快速(全扩张速率 90mm·a-1)、慢速(全扩张速率20～50mm·a-1)和超慢速(全扩张速率20mm·a-1)扩张洋中脊和非洋中脊的洋壳1-D地震波速度结构剖面,通过筛选统计、求取平均值等方法对分类的洋壳1-D速度结构进行对比研究,获得了不同扩张速率下洋中脊洋壳速度结构差异以及洋中脊与非洋中脊洋壳速度结构差异的新认识:(1)快速、慢速和超慢速扩张洋中脊的平均正常洋壳厚度分别为6.4km、7.2km和5.3km,其中洋壳层2的厚度基本相似,洋壳厚度差异主要源自洋壳层3;其洋壳厚度变化范围分别为4.9～8.1km、4.6～8.7km和4.2～10.2km,随着洋中脊扩张速率减小,洋壳厚度的变化范围逐渐增大;(2)快速扩张洋中脊的洋壳速度大于慢速和超慢速,可能与快速扩张脊洋壳生成过程中深部高密度岩浆上涌比较充足有关;(3)非洋中脊(10Ma)的洋壳比洋中脊(10Ma)的洋壳厚～0.3km,表明洋壳厚度与洋壳年龄有一定的正相关性.  相似文献   

环境激素氰戊菊酯和有机锡对轮虫生活史特征的影响     

朱玮阁  李孙根  吕林兰  杨家新 《湖泊科学》2009,21(5):687-692

采用单"克隆"培养和群体培养的方法,研究了具有环境雌激素效应药物氰戊菊酯(Fenvalerate)和雌性雄性化激素效应药物三丁基氯化锡(TBTC)对萼花臂尾轮虫(Brachionus calyciflorus)生命周期中各发育阶段的历时以及种群增长的影响,结果表明,氰戊菊酯和TBTC对萼花臂尾轮虫的生长发育和种群增长有明显的效应,氰戊菊酯使生殖期延长(200和1000μg/L),生殖后期缩短,平均寿命也缩短(除1000μg/L),总产卵量和种群增长率升高;而经TBTC处理生殖前期延长(1和5μg/L),生殖期和生殖后期缩短,平均寿命也缩短,总产卵量和种群增长率较对照组也有下降,批次携卵量也受到两种药物的影响,且萼花臂尾轮虫的总产卵量随着氰戊菊酯和TBTc的浓度呈曲线相关,氰戊菊酯:Y=-0.6745X2+6.6884X+5.855(R2=0.7027);TBTC:Y=0.2054X2-2.3 178X+16.666(R2=0.6535),研究表明环境雌激素氰戊菊酯和雌性雄性化激素TBTC对萼花臂尾轮虫生活史特征影响表现出一定差异.  相似文献   

Airborne laser scanning: existing systems and firms and other resources     

《ISPRS Journal of Photogrammetry and Remote Sensing》1999,54(2-3):164-198

This article gives an overview of resources on airborne laser scanning (ALS). The main emphasis is on existing systems and firms, especially commercial ones. Through a very time-consuming search and with the help of numerous persons from firms, organisations and other colleagues, a quite complete survey of existing commercial systems, including detailed system parameters, has been compiled. This survey is by far the most complete and up-to-date information available today on commercial ALS. Additional data on contact information, links and, in some cases, a short background is given for firms involved in ALS (manufacturers, service providers, owners). A summary of other non-commercial and research systems, mainly of NASA, and respective links is presented. Finally, some other useful WEB links are given. The developments in ALS have been very rapid the last 1–2 years. This overview reflects these developments and describes rather completely the current situation, thus, being useful for all persons involved in ALS one way or another.  相似文献   

末次盛冰期以来南海北部神狐海域沉积有机质的组成特征及其古气候/环境意义     

雷艳  胡建芳  向荣  付少英  李永祥  曹怀仁 《海洋学报》2017,39(11):75-84

通过对两根沉积柱GHE27L和GHE24L的总有机碳（TOC）、总氮（TN）、C/N比值及稳定碳同位素（δ13C_org）的分析,本文探讨了21.1 ka BP以来南海北部陆坡神狐海域沉积有机质的组成特征及可能的古气候/环境信息。沉积柱GHE27L的TOC含量、TN含量、C/N比值及δ13C_org值分别为0.53%~1.81%,0.07%~0.18%,8.2~16.0和-23.6‰~-20.3‰。沉积柱GHE24L各参数则分布为0.45%~1.65%,0.09%~0.24%,5.3~12.2和-22.6‰~-20.4‰。沉积柱总体有机质的剖面变化显示,末次盛冰期以来南海北部沉积有机质具有海洋和陆地混合来源,但以海洋有机质来源为主。冰期陆源有机质对总有机质的相对贡献比全新世高。末次盛冰期南海北部气候相对干旱,C₄植被发育。全新世夏季风增强、降雨增多。自2.0 ka BP以来,人类活动对南海北部海洋初级生产力产生一定的影响。  相似文献   

海岸带星载高光谱遥感影像预处理方法   总被引：6，自引：1，他引：6  

张东  张鹰  李欢 《海洋科学进展》2009,27(1)

以星载Hyperion L1R高光谱影像数据为研究对象,详细分析了完整的影像预处理流程及相关算法,包括利用像元灰度斜率阈值法、波段全局归一化法和归一化差值植被指数法实现影像的坏线修复、垂直条纹去除以及潮滩研究区的地物分离.然后结合FLAASH大气校正处理以及几何校正处理,得到潮滩地表真实光谱反射率影像.研究结果表明,该流程为潮滩地物进一步的高光谱定量遥感解译提供了必要的技术支撑.  相似文献   

Early Cretaceous mantle upwelling and melting of juvenile lower crust in the Middle-Lower Yangtze River Metallogenic Belt: Example from Tongshankou Cu-(MoW) ore deposit     

《Gondwana Research》2020

The linkage between intracontinental extension and the Early Cretaceous Cu-Mo-W polymetallic metallogenesis in the Middle-Lower Yangtze River Belt (MLYRB) has long been a subject of controversy due to the lack of convincing petrogenetic evidence to identify the nature of magmatic sources and their geological histories during extensional mantle upwelling. Here we present new zircon UPb ages, isotopic and geochemical data for granodiorites, quartz diorites and mafic microgranular enclaves (MMEs) in the Tongshankou area. Comparing the MMEs with their host porphyries, the different ratios of incompatible elements and the similar formation ages, coupled with quenched margins and the xenocrysts in the MMEs, indicate that the MMEs was most likely formed by mixing between mafic magma and their host felsic magma. The MMEs share similar geochemical and isotopic characteristics with the Cretaceous mafic rocks from MLYRB, indicating that MMEs were mostly derived from an enriched lithospheric mantle source without adakitic characteristics. Mixing of a crustal melt derived by melting of an amphibolite bearing juvenile lower crust with a mantle melt derived from melting of enriched lithospheric mantle can account for the generation of the Tongshankou prophyries. The melting of juvenile mafic lower crust and enriched lithospheric mantle is suggested to be caused by upwelling of asthenospheric mantle and the reactivity of trans-lithospheric faults in the intracontinental extensional environment. Our results therefore highlight that juvenile mafic lower crust beneath the Yangtze plate is one of the likely source for ore-forming magmatic rocks in the Early Cretaceous.  相似文献   

三种算法联合迭代反演求取最佳剩余静校正量   总被引：5，自引：1，他引：5       下载免费PDF全文

程金星  董敏煜 《地球物理学报》1996,39(3):416-423

估算剩余静校正量可看作是以激发点及接收点剩余静校正量为模型参数的、以叠加能量为目标函数的全局最优值的搜索问题．当地震记录的剩余静校正量大而信噪比较低时，应用相关统计法不能有效地拾取静校正量．本文分别采用了ＣＭＰ道集内道间互相关法、图像边缘提取的Ｌａｐｌａｃｉａｎ算法及ＤＦＰ算法，三种不同算法联合迭代反演可求取最佳的模型参数，使目标函数值达到或接近于全局最优．理论试算及实际资料处理效果表明，这种方法能够解决低信噪比及大静校正量造成的周期跳跃等静校正问题．  相似文献   

Terrain revised model for air temperature in mountainous area based on DEMs: A case study in Yaoxian county     

YANG Xin  TANG Guoan  XIAO Chenchao  DENG Fengdong 《地理学报》2007,17(4):399-408

In mountainous area, spatial interpolation is the traditional method to calculate air temperature by use of observed temperature data. Due to lack of sufficient observation data in mountainous areas many precise interpolation methods could give only coarse result which could not meet the demand of precision agriculture and local climate exploration. Based on DEMs of 25 m resolution, a reversed model is constructed, with which temperature is simu-lated to the corresponding slope unit from the solar radiation. Taking Yaoxian county as a test area, and mean monthly temperature data as basic information sources, which are collected from 15 weather stations around Yaoxian county in Shaanxi province from the year of 1970 to 2000, a simulation for the solar radiation cell by cell is completed. By simulating solar radia-tion at each slope and flat cell unit, the terrain revised temperature model could be realized. A comparison between the simulated temperature and the radiation temperature from TM6 thermal infrared image shows that the terrain improved model gets a finer temperature dis-tribution at local level. The accuracy of simulated temperature in mountainous area is higher than it is in flat area.  相似文献