High-frequency ocean radar derived characteristics of sea surface currents in the Ariake Sea,Japan     

Kazuhiro Aoki  Tomoya Kataoka 《Journal of Oceanography》2018,74(4):431-437

Composite analysis was conducted using high-frequency radar data obtained during 2006–2015 in order to gain a better understanding of the current field in the Ariake Sea. The seasonally averaged surface current in the Ariake Sea was directed southward in all seasons, except around river mouths during summer. Heavy rainfall enhanced the outflow along the eastern coast of the Shimabara Peninsula from Isahaya Bay to the southern area 2–5 days after heavy rainfall. Spring–neap differences were clearly seen in the southward current along the Shimabara Peninsula. Interannual variation in the M₂ tidal current amplitude was synchronized with the lunar nodal cycle.  相似文献   

Variability in Particle Mixing Rates in Sediments with Polymetallic Nodules in the Equatorial Eastern Pacific as Determined from Measurements of Excess <Superscript>210</Superscript>Pb     

Kiseong Hyeong  Inah Seo  Hyun-Bok Lee  Chan Min Yoo  Sang-Bum Chi  In Kwon Um 《Ocean Science Journal》2018,53(2):355-368

Radionuclide activities of ²¹⁰Pb and ²²⁶Ra were measured to determine bioturbation coefficients (D_b) in seven sediment cores from the Korean licensed block for polymetallic nodules in the Clarion–Clipperton Fracture Zone. Variability in D_b is considered in the context of the sedimentological, geochemical, and geotechnical properties of the sediments. D_b values in the studied cores were estimated using a steady-state diffusion model and varied over a wide range from 1.1 to 293 cm²/yr with corresponding mixing depths (L) of 26 to 144 cm. When excepting for spurious results obtained from cores where diffusive mixing does not apply, D_b values range from 1.1 to 9.0 cm²/yr with corresponding mixing depths (L) of 26 to 63 cm. Such wide variability in D_b and L values is exceptional in sites with water depths of ～5000 m and is attributed in this study to an uneven distribution of sediment layers with different shear strengths and total organic carbon (TOC) contents, caused by erosion events. The studied cores can be grouped into two categories based on lithologic associations: layers with high maximum shear strength (MSS) and low TOC content, showing a narrow range of D_b values (1.1–9.0 cm²/yr); and layers with low MSS and high TOC content, yielding much higher D_b values of over 30 cm²/yr. The distribution of different lithologies, and the resultant spatial variability in MSS and labile organic matter content, controls the presence and maximum burrowing depth of infauna by affecting their mobility and the availability of food. This study provides a unique case showing that shear strength, which relates to the degree of sediment consolidation, might be an important factor in controlling rates of bioturbation and sediment mixing depths.  相似文献   

Evolution Characteristics of Government-Industry-University-Research Cooperative Innovation Network for China’s Agriculture and Influencing Factors: Illustrated According to Agricultural Patent Case   总被引：1，自引：0，他引：1  

Erling Li  Fei Yao  Jiaxin Xi  Chunyang Guo 《中国地理科学(英文版)》2018,28(1):137-152

Under the special background of China, the cooperative innovation between different government-industry-university-research institutes plays an increasingly important role in the agricultural field. However, the existing literature has paid little attention to it. Considering the cooperation patents, published in the agriculture field stemming from the Full-text Database of China Patents as the study object, the spatial and institutional attribute of the authors as the data source, and by combining the social network and spatial econometrics analysis, this paper analyzes the structure evolution characteristics of cooperative innovation networks of agricultural government-industry-university-research institute in the city level of China in 1985–2014, based on the triple helix theory, with the influence factors discussed. This shows that, 1) since 1985, China's agricultural innovation level has been substantially increased, but the development degree of the cooperative innovation network is low, and the patent cooperation mainly relies on authors in the same unit; 2) enterprises play a leading role in the agricultural cooperative innovation. The effect of the government and hybrid organizations driven by the government is not obvious; 3) the cooperative innovation in the province and city dominates, and a multi-pole pattern has been formed. The cooperative innovation network structure evolves from a single helix empty core and double helix multi core to a double helix hierarchical network; 4) the city's science, education funding and personnel investment are key factors determining the agricultural cooperative innovation, while the agricultural development of the city presents slight negative impacts on it. The spatial mismatch of supply and demand is present in the technical cooperative innovation of China's agriculture. Therefore, the science enhancement and education investment to big agricultural provinces should be promptly implemented.  相似文献   

Impacts of tourism development on the physical environment of Mussoorie,a hill station in the lower Himalayan range of India     

Sangeeta Sundriyal  Vijay Shridhar  Sandeep Madhwal  Kamal Pandey  Vikram Sharma 《山地科学学报》2018,15(10):2276-2291

Tourism in mountainous regions is a significant source of revenue generation. However, it has also been associated with many adverse environmental consequences. This study aims at assessing the negative impacts of the incessant upsurge in tourism development on the physical environment of Mussoorie, a well-known mountain tourist destination in India. The impact indicators for the region were identified and assessed by qualitative and quantitative analysis of field observations. The observations indicated the aggravation of traffic congestion, atmospheric pollution, undisposed solid waste, water scarcity and infrastructure unavailability as the prevalent issues, especially during the peak tourist months. The extent of the consequential damage to the environment was evaluated by conducting an assessment of tourism-induced human disturbance on the natural landscape of the town. Slope, slope aspect, vegetation cover, road network and drainage network were incorporated as the determining landscape attributes to prepare thematic maps of landscape quality (perceivable intrinsic properties) and landscape fragility (vulnerability to anthropogenic disturbances) using GIS technique. An absorption capacity map was finally prepared to characterize the study area into regions of different conservation needs. The results identified the need for planning appropriate preservation strategies for different tourist places in the town. The study can be used by the policy makers for implementing the regulatory measures against potential disturbances due to mass-tourism.  相似文献   

Combining pixel and object based image analysis of ultra-high resolution multibeam bathymetry and backscatter for habitat mapping in shallow marine waters     

Daniel Ierodiaconou  Alexandre C. G. Schimel  David Kennedy  Jacquomo Monk  Grace Gaylard  Mary Young  Markus Diesing  Alex Rattray 《Marine Geophysical Researches》2018,39(1-2):271-288

Habitat mapping data are increasingly being recognised for their importance in underpinning marine spatial planning. The ability to collect ultra-high resolution (cm) multibeam echosounder (MBES) data in shallow waters has facilitated understanding of the fine-scale distribution of benthic habitats in these areas that are often prone to human disturbance. Developing quantitative and objective approaches to integrate MBES data with ground observations for predictive modelling is essential for ensuring repeatability and providing confidence measures for habitat mapping products. Whilst supervised classification approaches are becoming more common, users are often faced with a decision whether to implement a pixel based (PB) or an object based (OB) image analysis approach, with often limited understanding of the potential influence of that decision on final map products and relative importance of data inputs to patterns observed. In this study, we apply an ensemble learning approach capable of integrating PB and OB Image Analysis from ultra-high resolution MBES bathymetry and backscatter data for mapping benthic habitats in Refuge Cove, a temperate coastal embayment in south-east Australia. We demonstrate the relative importance of PB and OB seafloor derivatives for the five broad benthic habitats that dominate the site. We found that OB and PB approaches performed well with differences in classification accuracy but not discernible statistically. However, a model incorporating elements of both approaches proved to be significantly more accurate than OB or PB methods alone and demonstrate the benefits of using MBES bathymetry and backscatter combined for class discrimination.  相似文献   

Global Statistical Assessment and Cross-Calibration with Jason-2 for Reprocessed HY-2 A Altimeter Data     

Maofei Jiang  Ke Xu  Yalong Liu 《Marine Geodesy》2018,41(3):289-312

HY-2 A (Haiyang-2 A) satellite was launched on August 16, 2011 and radar altimeter is one of its main payloads. We reprocessed two years of HY-2 A altimeter sensor geophysical dataset records (SGDR) data. This paper presents the main results in terms of reprocessed HY-2 A altimeter data quality: verification of data availability and validity, monitoring several relevant altimeter parameters, and assessment of the HY-2 A altimeter system performances. A cross-calibration analysis of reprocessed HY-2 A altimeter data with Jason-2 was conducted. The reprocessed HY-2 A altimeter data show good quality and have a low level of noise with respect to Jason-2. The same geophysical correction methods were used to calculate the sea surface height (SSH) for the two missions. The mean standard deviations of the crossover differences for HY-2 A and Jason-2 are 5.24 cm and 5.34 cm, respectively. The mean standard deviation of the crossover differences between HY-2 A and Jason-2 is 5.37 cm. These show that HY-2 A can provide SSH measurements at almost the same level of accuracy as Jason-2. The relative SSH bias between HY-2 A and Jason-2 due to the Ultra Stable Oscillator (USO) drift is obviously observed, and it can affect the calculation of mean sea level and should be further studied and corrected.  相似文献   

Erratum to: Relationships between intensity of the Kuroshio current in the East China Sea and the East Asian winter monsoon     

Ming Yin  Xin Li  Ziniu Xiao  Chongyin Li 《海洋学报(英文版)》2018,37(9):119-119

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Multibeam sonar backscatter data processing     

Alexandre C. G. Schimel  Jonathan Beaudoin  Iain M. Parnum  Tim Le Bas  Val Schmidt  Gordon Keith  Daniel Ierodiaconou 《Marine Geophysical Researches》2018,39(1-2):121-137

Multibeam sonar systems now routinely record seafloor backscatter data, which are processed into backscatter mosaics and angular responses, both of which can assist in identifying seafloor types and morphology. Those data products are obtained from the multibeam sonar raw data files through a sequence of data processing stages that follows a basic plan, but the implementation of which varies greatly between sonar systems and software. In this article, we provide a comprehensive review of this backscatter data processing chain, with a focus on the variability in the possible implementation of each processing stage. Our objective for undertaking this task is twofold: (1) to provide an overview of backscatter data processing for the consideration of the general user and (2) to provide suggestions to multibeam sonar manufacturers, software providers and the operators of these systems and software for eventually reducing the lack of control, uncertainty and variability associated with current data processing implementations and the resulting backscatter data products. One such suggestion is the adoption of a nomenclature for increasingly refined levels of processing, akin to the nomenclature adopted for satellite remote-sensing data deliverables.  相似文献   

Dynamical system analysis of a five-dimensional cosmological model     

A. Savaş Arapoğlu  Ezgi Yalçınkaya  A. Emrah Yükselci 《Astrophysics and Space Science》2018,363(10):215

A five-dimensional cosmological model including a single perfect fluid is studied in the framework of dynamical system analysis. All the critical points of the system are listed with their stability properties and some representative phase diagrams are explicitly shown. It is found that the stabilization of extra dimension is possible and the observed flatness of the three-dimensional space is provided for certain ranges of the equation of state parameter of the fluid. The model suggested here can be considered as a simplified model for examining the possible effects of the extra dimensions in the early universe.  相似文献   

Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg     

Xiao-Man Tian  Li-Ying Zhu  Sheng-Bang Qian  Lin-Jia Li  Lin-Qiao Jiang 《天文和天体物理学研究(英文版)》2018,(2)

New multi-color BV RcIcphotometric observations are presented for the W UMa type eclipsing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119 yr,including CCD data to construct the O-C curve, and performed detailed O-C analysis. The O-C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic variation exist. The period is decreasing at a rate of P =-1.04(±0.18) × 10~(-10) d cycle~(-1) and, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P_3= 82.7(±3.6) yr and an amplitude of A = 0.028(±0.002) d may be explained by magnetic activity of one or both components or the light travel time effect caused by a distant third companion with M_3(i′= 90?) = 0.511 M_⊙.  相似文献