On using a generalized linear model to downscale daily precipitation for the center of Portugal: an analysis of trends and extremes     

Mário Pulquério  Pedro Garrett  Filipe Duarte Santos  Maria João Cruz 《Theoretical and Applied Climatology》2015,120(1-2):147-158

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北斗二号与北斗三号完好性参数设计差异分析     

辛洁  郭靖蕾  田翌君  郭睿  刘帅  张之学 《测绘科学》2021,46(5):14-19

针对能够标识北斗二号与北斗三号系统服务完好性的参数差异问题,该文从完好性参数定义、导航电文结构、参数内容和播发方式等方面对北斗二号和北斗三号系统完好性参数播发现状进行了比对分析,并对各类参数的工程实现情况进行了比较,结果表明:在兼容北斗二号基本导航服务相关系统完好性参数的基础上,北斗三号增加了可快速标识服务精度及预测精度的完好性参数;受多方面的约束与局限,北斗二号仅具备提供单频改正的广域差分增强服务的能力,且无相关国际标准规范支撑,而北斗三号为能获取国际民航组织测试认证,已立足于国际相关标准规范进行了可支撑单、双频改正的星基增强服务工程实现.  相似文献   

航空重力测量的空中数据处理与分析     

尹伟言  周睿  田源  赵俊  李琦 《测绘与空间地理信息》2021,44(10):196-199,203

针对航空重力测量的原始扰动数据,本文介绍了数据处理的一般流程,内容包括原始数据检查、零点漂移校正、平均高程面归算、交叉点搜寻、内符合精度评价、离散数据的格网化等方面,详细说明了每一步数据处理的理论模型,并通过工程实例对计算结果进行了讨论和分析,为今后开展大规模航空重力测量业务作出一定的尝试和探索.  相似文献   

河北矾山超钾质岩浆氧逸度及含水性特征的磷灰石地球化学记录     

舒小超  孟凡巍  陶瑞  王坤 《地质学报》2023,97(12):4101-4116

产于华北克拉通北缘的晚三叠世矾山超钾质碱性岩杂岩体主要由单斜辉石岩和辉石正长岩等组成,以发育内生磷灰石-磁铁矿矿床而闻名。本文选取矾山杂岩体中的磷灰石为研究对象,通过测试磷灰石的主微量元素及原位Sr-Nd同位素组成以探讨母岩浆的氧逸度及含水性特征。研究表明,矾山磷灰石以轻稀土元素富集、重稀土元素亏损为特征,显示出缺乏显著Ce异常的“右倾”的稀土配分型式,且具有较低的Ga含量及较高的δEu值,暗示杂岩体具有较高的岩浆氧逸度,这也得到了磷灰石Mn氧逸度计的支持。所有磷灰石以高Sr、低Y为特征,具有较高的Sr/Y(>30)和La/Yb(>90)比值,且Sr/Y与La/Yb存在明显的正相关关系,表明矾山超钾质岩浆具有较高的含水量。矾山磷灰石的原位Sr-Nd同位素投点位于地幔序列,明显偏离地壳趋势。母岩浆的“氧化且富水”特征是矾山杂岩体得以发生磷灰石-磁铁矿矿化的重要因素,其主要与板片俯冲过程中蚀变洋壳对岩石圈地幔的交代作用有关。通过对比矾山杂岩体与全球范围内其他地质环境中磷灰石的成分数据,发现具有“高Sr、低F、少Cl”特征的磷灰石可作为识别超钾质碱性岩杂岩体(及其相关金属矿床)的...  相似文献   

Time frame of 753–680 Ma juvenile accretion during the São Gabriel orogeny,southern Brazilian Shield     

L.A. Hartmann  R.P. Philipp  J.O.S. Santos  N.J. McNaughton 《Gondwana Research》2011,19(1):84-99

The time frame of the three main geological events in the Neoproterozoic Cambaí Complex, juvenile São Gabriel belt in the southern Brazilian Shield is established by integrating field mapping, back-scattered electron imaging and sensitive high-resolution ion microprobe (SHRIMP II) U–Pb dating of 96 zircon crystals from nine granitic and metasedimentary rock samples. The three events are: (1) voluminous flat-lying paragneisses (Cambaizinho Complex) and orthogneisses (Vila Nova gneisses) between 735 and 718 Ma, (2) tonalite–trondhjemite association (Lagoa da Meia-Lua Suite) between 710 and 690 Ma, and (3) late granodiorite intrusions (Sanga do Jobim Suite) at 680 Ma. An additional older volcanic event (Campestre Formation) was dated at 753 Ma. These results are most significant for the reconstruction of West Gondwana.  相似文献   

Hydrostratigraphic analysis of the Darling River valley (Australia) using electromagnetic induction data and a spatially constrained algorithm for quasi-three-dimensional electrical conductivity imaging   总被引：1，自引：0，他引：1  

John Triantafilis  Fernando Ac��cio Monteiro Santos 《Hydrogeology Journal》2011,19(5):1053-1063

Efforts are being made to improve the irrigation efficiency in the Murray-Darling River Basin, Australia, to deal with predicted rainfall decline and to reduce the incidence of secondary soil and water salinization. The latter commonly occurs as a result of locating water reservoirs upon relic drainage channels. To better manage irrigation, information is required about the spatial distribution of soil type and the stratigraphic features capable of redistributing deep-draining water. In previous research, electromagnetic (EM) induction instruments (e.g. EM38 and EM34) have been used to map the distribution of soil type, hydrological processes (e.g. deep drainage) and vadose-zone features. The aim of this research is to demonstrate how a joint inversion of EM38 and EM34 data, using a one-dimensional spatially constrained algorithm for quasi three-dimensional (quasi-3D) electrical conductivity imaging, can be used to infer the areal distribution of soil types and physiographic and hydrogeological units. The quasi-3D modeling of true electrical conductivity provides a framework for future environmental monitoring and management to mitigate the hydrological processes that drive localized secondary salinization in the study area.  相似文献   

Seasonal variability in somatic and reproductive investment of the bivalve Scrobicularia plana (da Costa, 1778) along a latitudinal gradient     

Sílvia Santos  Joana F.M.F. Cardoso  Célia Carvalho  Pieternella C. Luttikhuizen  Henk W. van der Veer 《Estuarine, Coastal and Shelf Science》2011

Monthly investment in soma and gonads in the bivalve Scrobicularia plana is described for three populations along its distributional range: Minho estuary, Portugal; Westerschelde estuary, The Netherlands and Buvika estuary, Norway. Seasonal cycles in body mass (BMI), somatic mass (SMI) and gonadal mass (GMI) indices were observed for all populations. In Portugal, BMI and SMI peaked in mid-autumn, while in The Netherlands both indices were at their highest in mid-spring. Norway showed a different pattern with two distinct peaks: one in mid-autumn and a second peak in spring. GMI reached maximum values in July in Portugal and Netherlands and in June in Norway. Overall, mean BMI and SMI were lower in Portugal while mean GMI was lower in Norway. The spawning period lasted the whole summer in Portugal, but was shorter (only two months) in The Netherlands and Norway. The reproductive investment in The Netherlands was significantly higher than in Portugal and Norway, with the lowest values being observed in Norway. Differences in annual cycles between populations were attributed to environmental factors, namely temperature and food availability. Temperature seems important in shaping the reproductive pattern with more northern populations showing shorter reproductive periods starting later in the year, and a lower reproductive output. In addition, winter water temperatures can explain the lower mean body and somatic mass values observed in Portugal. Food availability influenced the physiological performance of the species with peaks in somatic mass coinciding with phytoplankton blooms. This relation between physiological performance and environmental factors influences S. plana distribution, densities and even survival, with natural consequences on its commercial importance.  相似文献   

Structural-stratigraphic control on the Umitaka Spur gas hydrates of Joetsu Basin in the eastern margin of Japan Sea   总被引：1，自引：0，他引：1  

Antonio Fernando Menezes Freire  Ryo Matsumoto  Luiz Alberto Santos 《Marine and Petroleum Geology》2011,28(10):1967-1978

Integrated geological, geochemical, and geophysical exploration since 2004 has identified massive accumulation of gas hydrate associated with active methane seeps on the Umitaka Spur, located in the Joetsu Basin on the eastern margin of Japan Sea. Umitaka Spur is an asymmetric anticline formed along an incipient subduction zone that extends throughout the western side of the Japanese island-arc system. Seismic surveys recognized chimney structures that seem strongly controlled by a complex anticlinal axial fault system, and exhibit high seismic amplitudes with apparent pull-up structures, probably due to massive and dense accumulation of gas hydrate. Bottom simulating reflectors are widely developed, in particular within gas chimneys and in the gently dipping eastern flank of the anticline, where debris can store gas hydrates that may represent a potential natural gas resource. The axial fault system, the shape of the anticline, and the carrier beds induce thermogenic gas migration to the top of the structure, and supply gas to the gas hydrate stability zone. Gas reaching the seafloor produces strong seepages and giant plumes in the sea water column.  相似文献   

长江口水下三角洲泥质区近期沉积物粒度变化特征及其影响因素   总被引：4，自引：0，他引：4  

张瑞  汪亚平  高建华  潘少明 《海洋地质与第四纪地质》2011,(5):9-16

河口水下三角洲是河流和海洋环境共同作用的产物,沉积地层中蕴藏了许多环境变化信息.在长江口水下三角洲泥质区采集了柱样SC09,首先利用放射性同位素210Pb确定了沉积柱样的平均沉积速率,其次对沉积柱样以0.2 cm间隔进行高分辨率取样,获得了沉积物粒度参数,然后提取了沉积物粒度敏感组分,并对其进行了经验模态分解(EMD)...  相似文献   

极地近岸海洋环境监测系统的研制及应用   总被引：1，自引：0，他引：1  

王项南  刘松堂  石建军  田川  朱锐  麻常雷 《海洋技术学报》2011,30(2):35-40

目前极地海洋环境监测只能采用船基调查方式在南极夏季进行,在国家“十一五”863计划的支持下,设计研制了极地近岸海洋环境自动监测系统,该系统能够对包括温度、盐度、深度、pH、有效光合辐照度(PAR)、氧化还原电位(ORP)、叶绿素、海流等在内的生态要素及动力要素进行自动长期监测.该系统布放在南极长城站近岸海域,获得了大量...  相似文献