Detection of macroalgae blooms by complex SAR imagery

Increased frequency and enhanced damage to the marine environment and to human society caused by green macroalgae blooms demand improved high-resolution early detection methods. Conventional satellite remote sensing methods via spectra radiometers do not work in cloud-covered areas, and therefore cannot meet these demands for operational applications. We present a methodology for green macroalgae bloom detection based on RADARSAT-2 synthetic aperture radar (SAR) images. Green macroalgae patches exhibit different polarimetric characteristics compared to the open ocean surface, in both the amplitude and phase domains of SAR-measured complex radar backscatter returns. In this study, new index factors are defined which have opposite signs in green macroalgae-covered areas, compared to the open water surface. These index factors enable unsupervised detection from SAR images, providing a high-resolution new tool for detection of green macroalgae blooms, which can potentially contribute to a better understanding of the mechanisms related to outbreaks of green macroalgae blooms in coastal areas throughout the world ocean.     

Rectangular footing on soil with depth-degrading stiffness: Vertical and rocking impedances under conditional existence of surface waves

The response of rectangular rigid footings resting on an elastic soil of shear modulus decreasing monotonically with depth is studied. Such profiles are typically encountered after ground improvement. The propagation characteristics of SV/P surface waves are investigated, showing the appearance of cut-off frequencies above which surface waves do not exist. The semi-analytical method of the subdivision of the footing/soil contact area is then used for solving the boundary value problem, whereby the influence functions for the sub-regions are determined by integration of the corresponding surface-to-surface Green׳s functions. Impedance functions are presented over a wide range of frequencies for typical values of the non-homogeneity parameters, the Poisson׳s ratio and the foundation geometry. The salient features that are associated with the non-homogeneity and the appearance of cut-off frequencies are elucidated.     

Utilization pattern of Olympic parks and its application in Beijing

With great promotion of mega-events in both quantities and qualities in China, the research of Mega-events has been increased. As a global hallmark event, the Olympics, with their enormous scale, universal at- traction for the media and tremendous political significance, have increasingly drawn attention from the researchers. It is obvious that Beijing has been greatly impacted by the 2008 Olympic Games as the host. The event aroused close attention of researchers, especially the problem how the Olympic stadiums and facilities can be utilized after Olympic Games. The paper employed 3 methods to conduct a survey, that is, sending questionnaires to tourists, in- terviewing with government officers, and collecting information about former Olympic Parks from Internet and literatures. The utilization of former Olympic Parks after Games was summarized and some experiences were refined. Besides, 3 main bodies including government, business operators and visitors which formed basic driving forces to influence the park′s use were analyzed. At the same time, the paper believes that 3 topics affect the park′s utilization involving ′prepare to use′, ′how to use it′ and ′how to manage it′, and Beijing Olympic Park can also follow that thinking and reference in the further practices. Based on it, suggestions are given that Beijing Olympic Park can be planned spatially from 3 layers, the point, line and area, based on their function and infrastructure in the Games, and the area would be shaped as a new urban center with multi-functions while Mega-events and sport events are still the main content of the park.     

利用背景噪声互相关观测近对跖点台站间体波格林函数

本文利用秦岭周边和南美地区的部分台站2012—2014年记录的地震事件垂直分量数据,获取了166个台站对之间的互相关函数,从中观测到了近对跖点台站之间的体波格林函数.在此基础上,我们计算了理论地震图的互相关,其结果与实际数据获得的结果很相似,推测格林函数的能量来源应主要是大地震引起的地球自由振荡.更进一步的研究表明,不同的震源机制对于互相关结果中不同震相的振幅有较大影响,走滑断层引起的地震并不能产生较好的互相关结果.通过对比不同位置台站对的互相关结果,本文认为互相关得到的体波格林函数包含了传播路径信息.     

Equipartitioning is not sufficient for Green's function extraction

The extraction of the Earth's Green's function from field fluctuations is a rapidly growing area of research.The principle of Green's function extraction is often related to the requirement of equipartitioning,which stipulates that the energy of field fluctuations is distributed evenly in some sense.We show the meaning of equipartitioning for a variety of different formulations for Green's function retrieval.We show that equipartitioning is not a sufficient condition,and provide several examples that illustrate this point.We discuss the implications of lack of equipartitioning for various schemes for the reconstruction of the Green's function in seismology.The theory for Green's function extraction is usually based on a statistical theory that relies on ensemble averages.Since there is only one Earth,one usually replaces the ensemble average with a time average.We show that such a replacement only makes sense when attenuation is taken into account,and show how the theory for Green's function extraction for oscillating systems can be extended to incorporate attenuation.     

Siliceous microfossil succession in the recent history of Green Bay,Lake Michigan

Quantitative analysis of siliceous microfossils in a ²¹⁰Pb dated core from Green Bay of Lake Michigan shows clear evidence of eutrophication, but a different pattern of population succession than observed in the main deposition basins of the Great Lakes. Sediments deposited prior to extensive European settlement (ca A.D. 1850) contain high relative abundance of chrysophyte cysts and benthic diatoms. Quantity and composition of microfossils deposited during the pre-settlement period represented in our core is quite uniform, except for the 30–32 cm interval which contains elevated microfossil abundance and particularly high levels of attached benthic species. Total microfossil abundance and the proportion of planktonic diatoms begins to increase ca 1860 and rises very rapidly beginning ca 1915. Maximum abundance occurs in sediments deposited during the 1970's, with a secondary peak in the late 1940's — early 1950's. Increased total abundance is accompanied by increased dominance of taxa tolerant of eutrophic conditions, however indigenous oligotrophic taxa, particularly those which are most abundant during the summer, are not eliminated from the flora, as in the lower Great Lakes. It appears that a combination of silica resupply from high riverine loadings and replacement of indigenous populations by periodic intrusions of Lake Michigan water allow sequential co-existence of species usually exclusively associated with either eutrophic or oligotrophic conditions.     

Structure of fougerite and green rusts and a thermodynamic model for their stabilities

Fougerite is a new iron oxide, a mixed M(II)–M(III) hydroxide, a member of the green rust group. Its structure consists of a brucitic layer of Fe(III)–Fe(II)–Mg(II), where the excess of the positive charge due to Fe³⁺ is compensated in the interlayer by anions. The limits of composition are structurally and geochemically constrained, and the stabilities of the mineral and green rusts are obtained by a thermodynamic model of a regular solid solution, for different compensating anions and for any allowed composition of the brucitic layer.     

Improvement of kerogen structural interpretations based on oxidation products isolated from aqueous solutions

A detailed investigation of kerogen oxidation products remaining in aqueous solutions after the usual isolation of degradation products by extraction with ether or precipitation, was carried out for the first time in kerogen structural studies. Three shale samples were investigated: Green River shale (type I kerogen), Toarcian shale, Paris Basin (type II), and Mannville shale, Canada (type III). The yields of acids from aqueous solutions were noticeable: 12.98, 15.32 and 22.32%, respectively, based on initial kerogens. Qualitative and quantitative capillary GC/MS analysis showed that the ratios of different kinds of identified acids depended much on the type of precursor kerogen. Some of the acids identified in aqueous solutions have not been found earlier among the degradation products of the same kerogen samples, or were obtained in different ranges and yields. Consequently, slight modifications were suggested of the image on the nature of various types of kerogens based on examination of ether-soluble acids only. Namely, slightly higher proportions of aromatic and alkane-polycarboxylic acids in the total oxidation products of both type I and type II kerogens indicated larger participation of aromatic and alicyclic and/or heterocyclic structures in these two kerogens. On the other hand, for type III Mannville shale kerogen, a somewhat larger share of aliphatic type structures was demonstrated.     

2008 年与2009 年黄海绿潮漂移路径分析

利用卫星资料分析了2008年和2009年黄海绿潮的漂移路径的差异,基于QSCAT(Quick Scatterometer)卫星风场及海洋模式表层环流模拟结果,分析了绿潮漂移路径差异的动力机制。结果表明:2008(2009)年绿潮发生期间黄海海域以南东(偏南)风为主,江苏至山东半岛南岸海域表层平均流为偏北(东北)向,青岛附近海域低频余流为偏西(东)向流,致使绿潮的漂移方向为西北(东北)向,在青岛(烟台-威海)近岸海域发生聚集。2008年和2009年绿潮漂移路径差异,主要由海面风与表层环流的共同作用引起。通过对黄海海域海面风场和表层流场的早期预报,可以提前预判绿潮的影响区域和程度,为政府相关部门防灾减灾工作提供决策支持。