贵州高原起伏地形下日照时间的时空分布   总被引：1，自引：0，他引：1       下载免费PDF全文

袁淑杰  缪启龙  邱新法  谷小平 《应用气象学报》2008,19(2):233-237

由于坡度、坡向和地形之间相互遮蔽等局地地形因子的影响, 实际起伏地形下的日照时间与水平面上的日照时间有一定差异。该文建立了一种基于数字高程模型 (DEM) 的起伏地形下日照时间的模拟方法, 计算了起伏地形下贵州高原100 m×100 m分辨率日照时间的时空分布。结果表明:坡度、坡向、地形遮蔽对日照时间的影响较大, 实际起伏地形下日照时间的空间分布具有明显地域特征。1月太阳高度角较低, 坡度、坡向的作用非常明显, 地形遮蔽面积较大, 日照时间的空间差异较多, 日照时间为16~142 h, 最大值约为最小值9倍; 7月太阳高度角较高, 地形遮蔽面积相对较小, 日照时间的空间差异相对较少, 日照时间为133~210 h, 最大值为最小值1.6倍, 但由于7月日照时间相对较多, 局地地形对日照时间影响仍明显。4月、10月日照时间及其变化幅度介于1月和7月之间。  相似文献   

Seafloor Habitat Mapping on the Oregon Continental Margin: A Spatially Nested GIS Approach to Mapping Scale,Mapping Methods,and Accuracy Quantification     

Andrew Lanier  Chris Romsos  Chris Goldfinger 《Marine Geodesy》2013,36(1-2):51-76

We implement a geographic information system (GIS) to map surficial geologic habitats (SGH) with varying scales at Nehalem Bank, Oregon, USA. Geologic interpretation was first used to produce a regional-scale SGH map of mega habitats. Local-scale algorithmic classification techniques were then implemented where data density and richness permitted the mapping of meso (10 m-1 km) macro scale (1–10 m) habitat features. We use a ranked-(data) density approach to assess the distribution and quality of input data for the regional SGH map. We then apply a virtual reference dataset and error matrix technique to assess the thematic accuracy of local-scale maps.  相似文献   

Processing Multibeam Backscatter Data     

Qiu-hua Tang  Xing-hua Zhou  Zhong-chen Liu  AND De-wen DU 《Marine Geodesy》2013,36(3):251-258

A new highly precise source of data has recently become available using multibeam sonar systems in hydrography. Multibeam sonar systems can provide hydrographic quality depth data as well as high-resolution seafloor sonar images. We utilize the seafloor backscatter strength data of each beam from multibeam sonar and the automatic classification technology so that we can get the seafloor type identification maps. In this article, analyzing all kinds of error effects in backscatter strength, data are based on the relationship between backscatter strength and seafloor types. We emphasize particularly analyzing the influences of local bottom slope and near nadir reflection in backscatter strength data. We also give the correction algorithms and results of these two influent factors. After processing the raw backscatter strength data and correcting error effects, we can get processed backscatter strength data which reflect the features of seafloor types only. Applying the processed backscatter strength data and mosaicked seafloor sonar images, we engage in seafloor classification and geomorphy interpretation in future research.  相似文献   

TEM investigations of South Atlantic Ridge 13.2°S hydrothermal area     

TAO Chunhui  XIONG Wei  XI Zhenzhu  DENG Xianming  XU Yixian 《海洋学报(英文版)》2013,32(12):68-74

According to the exploration contract about polymetallic sulfides in the SWIR （Southwest Indian Ridge） signed by China with the International Seabed Authority, to delineate sulfide minerals and estimate resource quantity are urgent tasks. We independently developed our first coincident loop Transient Electromagnetic Method （TEM） device in 2010, and gained the TEM data for seafloor sulfide at South Atlantic Ridge 13.2°S in June 2011. In contrast with the widely applied CSEM （Marine controlled-source electromagnetic） method, whose goal is to explore hydrocarbons （oil/gas） of higher resistivity than seawater from 102 to 103 m below the sea floor, the TEM is for low resistivity minerals, and the target depth is from 0 to 100 m below the sea floor. Based on the development of complex sulfide geoelectrial models, this paper analyzed the TEM data obtained, proposing a new method for seafloor sulfide detection. We present the preliminary trial results, in the form of apparent resistivity sections for both half-space and full-space conditions. The results cor- respond well with the observations of the actual hydrothermal vent area, and the detection depth reached 50-100m below the bed, which verified the capability of the equipment.  相似文献   

New discovery of seafloor hydrothermal activity on the Indian Ocean Carlsberg Ridge and Southern North Atlantic Ridge—progress during the 26th Chinese COMRA cruise   总被引：1，自引：0，他引：1  

TAO Chunhui  WU Guanghai  DENG Xianming  QIU Zhongyan  HAN Chenhu  LONG Yanmei 《海洋学报(英文版)》2013,32(8):85-88

The 26th Chinese COMRA (China Ocean Mineral Resources Research & Development Association) cruise was an important cruise. The Carlsberg Ridge (CR) of the Northwest Indian Ocean and the North Atlantic Ridge (NAR), in which less investigation has been carried out for hydrothermal activities, were investigated and studied during the first two legs of the 26th COMRA cruise. During the first leg, we found one hydrothermal activity field located in the CR at 3.5 -3.8 N on the Northwest Indian Ocean Ridge (NWIR), and sampled seafloor polymetallic sulfide deposits where only abnormalities were found before. During the second leg, we found a new hydrothermal anomaly field located in the NAR at 4 -7 N. The discovery of two hydrothermal and anomaly fields filled in the gap of hydrothermal investigation and study in the corresponding regions for China.  相似文献   

Liquefaction in the coastal environment: An analysis of case histories     

R. C. Chaney  H. Y. Fang 《Marine Georesources & Geotechnology》2013,31(3-4):343-370

Abstract

The stability of coastal and underwater slopes and seafloor sediments is of major importance for waives, breakwaters, pipelines, jacket platforms, and gravity platforms. A major source of instability in cohesionless sediments is the result of the liquefaction. This paper explores the various mechanisms causing liquefaction in the marine environment and then reviews a large number of case studies.  相似文献   

声速误差对圆走航水下控制点定位影响分析     

孙文舟  殷晓冬  夏文杰 《大地测量与地球动力学》2020,40(12):1299-1302

针对圆走航定位声速剖面测量不准确引起水下控制点坐标解算存在偏差的问题,首先介绍了声速不确定性对测距误差的影响,并将声速测距误差分成背景声速剖面误差、随机误差、测距误差长周期项和测距误差短周期项,再通过分析坐标改正数方程得到不同声速测距误差项对控制点坐标定位的影响。最后,设计2组仿真实验对该理论进行验证,实验结果与理论推导的结论一致。  相似文献   

West Pacific and North Indian Ocean Seafloor and Their Ocean-Continent Connection Zones: Evolution and Debates     

ZHANG Guowei  LI Sanzhong  GUO Anlin  SUO Yanhui 《《地质学报》英文版》2017,91(6):2283-2301

The Indian Ocean and the West Pacific Ocean and their ocean-continent connection zones are the core area of "the Belt and Road". Scientific and in-depth recognition to the natural environment, disaster distribution, resources, energy potential of “the Belt and Road” development, is the cut-in point of the current Earth science community to serve urgent national needs. This paper mainly discusses the following key tectonic problems in the West Pacific and North Indian oceans and their ocean-continent connection zones (OCCZs): 1. modern marine geodynamic problems related to the two oceans. Based on the research and development needs to the two oceans and the ocean-continent transition zones, this item includes the following questions. (1) Plate origin, growth, death and evolution in the two oceans, for example, 1) The initial origin and process of the triangle Pacific Plate including causes and difference of the Galapagos and West Shatsky microplates; 2) spatial and temporal process, present status and trends of the plates within the Paleo- or Present-day Pacific Ocean to the evolution of the East Asian Continental Domain; 3) origin and evolution of the Indian Ocean and assembly and dispersal of supercontinents. (2) Latest research progress and problems of mid-oceanic ridges: 1) the ridge-hot spot interaction and ridge accretion, how to think about the relationship between vertical accretion behavior of thousands years or tens of thousands years and lateral spreading of millions years at 0 Ma mid-oceanic ridges; 2) the difference of formation mechanisms between the back-arc basin extension and the normal mid-oceanic ridge spreading; 3) the differentials between ultra-slow dian Ocean and the rapid Pacific spreading, whether there are active and passive spreading, and a push force in the mid-oceanic ridge; 4) mid-oceanic ridge jumping and termination: causes of the intra-oceanic plate reorganization, termination, and spatial jumps; 5) interaction of mantle plume and mid-oceanic ridge. (3) On the intra-oceanic subduction and tectonics: 1) the origin of intra-oceanic arc and subduction, ridge subduction and slab window on continental margins, transform faults and transform-type continental margin; 2) causes of the large igneous provinces, oceanic plateaus and seamount chains. (4) The oceanic core complex and rheology of oceanic crust in the Indian Ocean. (5) Advances on the driving force within oceanic plates, including mantle convection, negative buoyancy, trench suction and mid-oceanic ridge push, is reviewed and discussed. 2. The ocean-continent connection zones near the two oceans, including: (1) Property of continental margin basement: the crusts of the Okinawa Trough, the Okhotsk Sea, and east of New Zealand are the continental crusts or oceanic crusts, and origin of micro-continent within the oceans; (2) the ocean-continent transition and coupling process, revealing from the comparison of the major events between the West Pacific Ocean seamount chains and the continental margins, mantle exhumation and the ocean-continent transition zones, causes of transform fault within back-arc basin, formation and subduction of transform-type continental margin; (3) strike-slip faulting between the West Pacific Ocean and the East Asian Continent and its temporal and spatial range and scale; (4) connection between deep and surface processes within the two ocean and their connection zones, namely the assembly among the Eurasian, Pacific and India-Australia plates and the related effect from the deep mantle, lithosphere, to crust and surface Earth system, and some related issues within the connection zones of the two oceans under the super-convergent background. 3. On the relationship, especially their present relations and evolutionary trends, between the Paleo- or Present-day Pacific plates and the Tethyan Belt, the Eurasian Plate or the plates within the Indian Ocean. At last, this paper makes a perspective of the related marine geology, ocean-continent connection zone and in-depth geology for the two oceans and one zone.  相似文献   

崎岖海底OBC地震数据全波形反演策略     

赫建伟  周家雄  王宇  张盼  王新领 《世界地质》2017,36(1):274-282

针对崎岖海底引起的波场传播和全波形反演处理的复杂性,本文提出相应的反演策略。通过对崎岖海底网格特殊处理解决正演和静校正时的地形近似问题。全波形反演采用快速多尺度算法、宽角补偿策略和静校正处理策略。结果表明,该反演策略在大大提高反演效率的同时,能兼顾深部和远偏移距反演效果,并能针对海水误差情况选择策略,在崎岖海底情况下得到好的全波形反演结果。  相似文献   

海底天然气水合物中甲烷逸出对全球气候的影响   总被引：4，自引：3，他引：1  

方银霞  黎明碧  初凤友 《地球物理学进展》2004,19(2):286-290

全球气候变化会降低海底天然气水合物的稳定性导致水舍物失稳分解,反过来天然气水合物分解释放出的大量甲烷气,又会对全球气候变化产生巨大的影响,地质历史上许多重大地质事件(如LPTM事件)都可能与天然气水合物的分解释气作用有关．除了地质历史上强烈的甲烷突然释放事件,现代海底的渗漏或喷口也连续不断地向海水甚至大气输入甲烷,从而影响着全球气候变化．由于天然气水合物中甲烷逸出对全球气候影响的研究刚刚起步,还缺乏海洋沉积物和海水中甲烷传输的恰当模式,甲烷在海水中的溶解度、甲烷的氧化作用及上升流等因素对其的影响程度,以及它对大气甲炕和二氧化碳浓度变化的具体贡献等目前还很不清楚,亟需深化研究．  相似文献