干旱区水资源费的构成与确定   总被引：5，自引：2，他引：3  

李斌  樊胜岳  周立华 《中国沙漠》2001,21(1):50-55

干旱区水资源的稀缺性,使得确定缺水地区合理的水价体系,制定有效的水价政策,充分体现水资源的高"价值",成为合理利用水资源急需解决的问题。从分析水资源费的构成要素,并从边际机会成本的角度对水资源的价格进行了探讨,认为水资源的价格不是由其平均机会成本,而是由其边际机会成本决定的,水资源使用者所付的价格应等于社会负担的自然资源利用与耗竭的代价——边际机会成本。  相似文献   

张性边缘海的成因演化特征及沉积充填模式——以珠江口盆地为例   总被引：13，自引：0，他引：13  

张志杰  于兴河  侯国伟  陈瑞 《现代地质》2004,18(3):284-289

珠江口盆地的形成和演化过程经历了晚白垩世至渐新世的裂陷-晚渐新世至中中新世的热沉降-晚中新世至今的断块升降3个演化阶段,沉积了陆相-半封闭海相-开阔海相3套不同的沉积体系组合。总结归纳出珠江口盆地新生代3个阶段的沉积充填模式,并发现：裂陷阶段以充填式堆积和河湖沉积为特征,形成盆地最重要的湖相烃源岩--文昌组泥岩;热沉降阶段以海陆交替、海相沉积体系为特征,为形成良好的储盖组合创造了条件,沉积了珠江口盆地内最主要的储油层系--珠海组、珠江组以及韩江组,主要为滨海相、三角洲相等碎屑岩沉积;晚期盆地整体下沉,区域性盖层形成。该沉积组合反映了张性边缘海盆地的演化特点,盆地演化与资源效应表现在裂陷期、热沉降期及断块升降期的生储盖配置,故勘探目的层段为热沉降阶段所形成的三角洲碎屑岩与陆棚碳酸盐岩。  相似文献   

夏季北冰洋无冰海域次表层暖水结构的形成机理   总被引：1，自引：0，他引：1  

王翠  赵进平 《海洋科学进展》2004,22(2):130-137

在夏季北冰洋的无冰海域,经常可以观测到次表层暖水现象,即在水深20～50m的范围内发生海水温度的极大值。建立了一个一维的热力学解析模式,用于研究夏季北冰洋次表层暖水的形成机制。模式的计算结果表明,太阳辐射作用是形成次表层暖水的关键因素。在北冰洋的开阔水域,大气吸收海洋热量的过程导致了海面温度下降,使温度极大值出现在次表层。海洋垂向湍流热扩散对次表层暖水温度有显著影响;当湍流热扩散较弱时,热扩散的范围较小,有利于形成次表层暖水。次表层暖水的位置随着时间的推移不断加深,温度不断增高。在北极,大气温度低于海面温度是普遍现象,次表层暖水经常发生。虽然当海面气温发生变化时,次表层海水温度结构会发生相应的变化,但次表层暖水结构形成之后,如果不受强烈天气过程的破坏,则会一直存在下去。按照本文的结论,随着北极气候变暖,海冰将进一步减少,次表层暖水现象还会明显增加,海洋对气候变化将有更加强烈的响应和反馈,对全球气候变化产生意义深远的影响。  相似文献   

Detection and classification of surface roughness in an Arctic marginal sea ice zone          下载免费PDF全文

M. Gupta  D. G. Barber  R. K. Scharien  D. Isleifson 《水文研究》2014,28(3):599-609

Sea ice dynamic and thermodynamic processes are important and highly variable elements of the marginal ice zone (MIZ). This study examines the detection and classification of statistically separable sea ice classes in the MIZ through a range of temporal and spatial scales. A helicopter‐based laser system was used to obtain large‐scale and a ship‐based laser profiler to identify small‐scale roughness types, respectively. The analysis of variance of surface height data from helicopter‐ and ship‐based laser systems, active microwave (AMW) C‐band backscattering data and passive microwave (PMW) (37 and 89 GHz) brightness temperature data reveal different classes that statistically differ from one another. We found significant statistical difference in variances in AMW data with six classes that differ in VV polarization, three classes in VH polarization, and five classes in HH polarization in the MIZ (e.g. snow‐covered first‐year ice, ice rubble, pancake ice, frost flowers, melt pond, flooded ice, and ice edge) of southeastern Beaufort Sea. The PMW emission was not as effective at discrimination, yielding only one statistically separable class. The results can potentially be extended to satellite‐based investigations of the MIZ at regional scales. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

基于Archimedean Copula函数的风浪联合统计分析     

董胜  翟金金  陶山山 《中国海洋大学学报(自然科学版)》2014,44(10):134-141

选取渤海海域某导管架平台24年的年最大波高和相应风速,基于Gumbel分布对2个边缘分布的拟合优度检验,采用Archimedean Copula函数族中的4种函数构建两变量联合概率分布模型,并进行了拟合优度评价。利用优选出的Clayton Copula函数,计算风浪联合分布的联合重现值。以海洋平台响应作为约束条件,进行了二维Clayton Copula函数的风浪联合统计分析。研究结果表明:基于Copula函数构造的二维分布,考虑了风浪之间的相关性,在相同重现值设计参数下,可以降低导管架平台的结构响应,从而可以降低海洋平台的环境条件设计标准。  相似文献   

Spatio-temporal distribution of dissolved sulfide in China marginal seas     

吴晓丹  吴斌  宋金明  李学刚 《中国海洋湖沼学报》2014,32(5):1145-1156

With sulfide increasingly recognized as an important parameter to assess the oxidation-reduction level in aqueous environment, research on its geochemical behavior is becoming important. Water samples collected in Bohai Sea(1–19 August, 2010), Yellow Sea(20–30 November, 2010) and East China Sea(3–17 June, 2010 and 1–10 November, 2010) were used to determine the occurrence and distribution of dissolved sulfide by methylene blue spectrophotometric method. Results show that:(1) horizontally, concentration of dissolved sulfide significantly varied from the coastal region to the open sea and profoundly influenced by physical processes. High values occurred in the river-sea boundary zone "marginal filter" due to rich riverine input, frequent upwelling and active exchange in shelf edge. Terrestrial input from adjacent rivers and the current cycling contributed to the high sulfide appeared in western Bohai Sea, eastern Shandong Peninsula, and northeast of Changjiang(Yangtze) River estuary. Especially, relative higher sulfide values occurred in Yellow Sea, which is consistent with the variation of salinity largely due to the hydrodynamic feature;(2) vertically, measurement of dissolved sulfide in bottom water was higher and more variable than that in surface water caused by the wind-induced resuspension and dissimilatory sulfate reduction. Moreover, nutrient-type profile clearly identified that oxidation plays a major role in the biogeochemistry cycle of sulfide in water;(3) seasonally, investigation for East China Sea in June and November reflected seasonal variation of Changjiang River Diluted Water, Kuroshio Current, and Taiwan Warm Current. Concentration in June was much higher than that sampled in November at most stations. Mean concentration of dissolved sulfide varied seasonally from 2.26 μg/L(June) to 1.16 μg/L(November) in surface and 3.00 μg/L(June) to 1.56 μg/L(November) in bottom. Progress in the field is slow and more effort is needed to ensure the accuracy and reliability of determination and estimate the natural or anthropogenic contribution of dissolved sulfide in ecosystems.  相似文献   

南海南北大陆边缘盆地构造演化差异性对油气成藏条件控制   总被引：6，自引：2，他引：4       下载免费PDF全文

解习农  张成  任建业  姚伯初  万玲  陈慧  康波 《地球物理学报》2011,54(12):3280-3291

南海大陆边缘盆地由于边界条件的差异,形成了离散型、走滑-伸展型和伸展-挠曲复合型3类陆缘盆地.这些盆地由于其构造演化差异性,导致了盆地沉积充填存在较大差异,相应地导致这些盆地油气成藏条件及油气资源量的巨大差异.南海北部离散型大陆边缘盆地主要发育湖相泥岩和海相泥岩烃源岩,尽管存在较好的湖相烃源岩,但由于各断陷分隔且面积较...  相似文献   

鄂尔多斯盆地东南部二叠系物源分析   总被引：9，自引：1，他引：8  

屈红军  马强  高胜利  梅志超  苗建宇 《地质学报》2011,85(6):979-986

近几年鄂尔多斯盆地东南部上古生界陆续发现新的天然气区带,显示出巨大的勘探潜力,因此对盆地东南部二叠系物源的研究对于确定储集砂体展布规律具有重要价值。以钻测井、岩心及周边露头资料为基础,通过露头剖面古流向测定、重矿物分析、边缘相分析、相带分析的方法,确定了研究区二叠系的物源方向;研究认为鄂尔多斯盆地东南部二叠系山西组与石盒子组物源可分为北北东、北北西及南部三个方向,以延安为中心区域属于汇水区;山2段南部物源影响范围较大,影响到延安以北区域;盒8段北部物源范围较大,越过了延安,相应的南部物源范围后撤。  相似文献   

华北陆块南缘燕山期花岗岩带岩浆演化:以小秦岭—外方山地区为例   总被引：2，自引：1，他引：1  

王振强  徐建昌  冯建之  祁冬梅  杨钢  孙卫志 《现代地质》2011,25(6):1032-1046

根据华北陆块南缘小秦岭—外方山地区中生代花岗岩的时空分布特征,将其形成过程划分为160～155 Ma(Ⅰ)、150～125 Ma(Ⅱ)、120～110 Ma(Ⅲ)3个期次,与中国北方大规模岩浆活动期次并不完全一致。这3期花岗岩的地球化学元素演化较为特殊,Ⅰ期花岗岩(南泥湖、上房沟等岩体)与Ⅲ期花岗岩的地球化学特征较为相似,均以异常高的K含量、明显的负Eu异常及重稀土元素分馏较弱或不分馏为主要特征,为A型花岗岩。Ⅱ期花岗岩为偏铝质—弱过铝质高钾钙碱性系列花岗岩,富集Rb、Th、U和K等大离子亲石元素,亏损Nb和Ta等高场强元素,P2O5含量随SiO2含量增加呈递减趋势,为I型花岗岩,大部分样品Sr>300.00×10-6,Y<19.00×10-6,Yb<1.90×10-6,具有埃达克岩的属性。时代由老至新,Ⅰ、Ⅱ、Ⅲ花岗岩呈现出A型—I型—A型的演化规律。Ⅰ期花岗岩形成于挤压构造背景下的局部伸展环境;Ⅱ期花岗岩则形成于华北陆块南缘构造体制转换阶段,是地壳加厚导致的下地壳部分熔融的产物;Ⅲ期花岗岩则是扬子与华北陆块拼合后,板块逐渐稳定,岩石圈发生伸展,下地壳岩石减压熔融形成的。  相似文献   

Bivariate frequency analysis: discussion of some useful concepts in hydrological application     

Sheng Yue  Peter Rasmussen 《水文研究》2002,16(14):2881-2898

Basic concepts such as conditional probability distributions, conditional return periods, and joint return periods are important to understand and to interpret multivariate hydrological events such as floods and storms. However, these concepts are not well documented in the open literature. This paper assembles and clarifies these concepts, and illustrates their practical utility. Relationships between joint return periods and univariate return periods are also derived. These concepts and relationships are demonstrated by applying a bivariate extreme value distribution to represent the joint distribution of flood peak and volume from an actual basin. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献