Optical closure of parameterized bio-optical relationships     

贺双颜  贺明霞 《中国海洋湖沼学报》2014,32(2):480-489

An optical closure study on bio-optical relationships was carried out using radiative transfer model matrix operator method developed by Freie Universitt Berlin.As a case study,the optical closure of bio-optical relationships empirically parameterized with in situ data for the East China Sea was examined.Remote-sensing refl ectance(R rs)was computed from the inherent optical properties predicted by these biooptical relationships and compared with published in situ data.It was found that the simulated R rs was overestimated for turbid water.To achieve optical closure,bio-optical relationships for absorption and scattering coeffi cients for suspended particulate matter were adjusted.Furthermore,the results show that the Fournier and Forand phase functions obtained from the adjusted relationships perform better than the Petzold phase function.Therefore,before bio-optical relationships are used for a local sea area,the optical closure should be examined.  相似文献   

Phytoplankton community characteristics in the coastal waters of the southeastern Arabian Sea Phytoplankton community characteristics in the coastal waters of the southeastern Arabian Sea     

MINU P  SHAJU S S  MUHAMED ASHRAF P  MEENAKUMARI B 《海洋学报(英文版)》2014,(12)

Remote sensing applications are important in the fisheries sector and efforts were on to improve the predic-tions of potential fishing zones using ocean color. The present study was aimed to investigat...  相似文献   

Seasonality of oceanic primary production and its interannual variability from 1998 to 2007     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

The seasonality of primary productivity plays an important role in nutrient and carbon cycling. We quantify the seasonality of satellite-derived, oceanic net primary production (NPP) and its interannual variability during the first decade of the SeaWiFS mission (1998 to 2007) using a normalized seasonality index (NSI). The NSI, which is based upon production half-time, t(1/2), generally becomes progressively more episodic with increasing latitude in open ocean waters, spanning from a relatively constant rate of primary productivity throughout the year (mean t(1/2) ~5 months) in subtropical waters to more pulsed events (mean t(1/2) ~3 months) in subpolar waters. This relatively gradual, poleward pattern in NSI differs from recent estimates of phytoplankton bloom duration, another measure of seasonality, at lower latitudes (~40°S–40°N). These differences likely reflect the temporal component of production assessed by each metric, with NSI able to more fully capture the irregular nature of production characteristic of waters in this zonal band. The interannual variability in NSI was generally low, with higher variability observed primarily in frontal and seasonal upwelling zones. The influence of the El Niño–Southern Oscillation on this variability was clearly evident, particularly in the equatorial Pacific, where primary productivity was anomalously episodic from the date line east to the coast of South America in 1998. Yearly seasonality and the magnitude of annual production were generally positively correlated at mid-latitudes and negatively correlated at tropical latitudes, particularly in a region bordering the Pacific equatorial divergence. This implies that increases of annual production in the former region are attained over the course of a year by shorter duration but higher magnitude NPP events, while in the latter areas it results from an increased frequency or duration of similar magnitude events. Statistically significant trends in the seasonality, both positive and negative, were detected in various patches. We suggest that NSI be used together with other phenomenological characteristics of phytoplankton biomass and productivity, such as the timing of bloom initiation and duration, as a means to remotely quantify phytoplankton seasonality and monitor the response of the oceanic ecosystem to environmental variability and climate change.  相似文献   

剪切应变异常带近等距控矿模式—以粤西河台金矿为例   总被引：4，自引：0，他引：4  

朱江建 《地质与勘探》2014,50(3):454-463

本文研究了河台金矿富矿体的分布规律并对河台金矿与富矿体有关的热液成矿期进行了构造-流体成矿数值模拟研究。研究表明,河台金矿的富矿体在平面上表现为左阶近等距的分布规律;剖面上也表现为近等距的分布规律,并都有北东向侧伏的规律。其中,据统计,河台金矿云西矿床相邻品位富集中心在侧伏方向上的距离为85~179m;河台金矿高村矿床相邻品位富集中心在侧伏方向上的距离为62~302m。剪切应变异常带是有利于发生剪切滑动与成矿的扩容区,且本区数值模拟产生的平面剪切应变异常带具有与富矿体分布特征一致的左阶近等距性。由此提出,剪切滑动之前剪切应变异常带的近等距性决定了剪切滑动后矿体的近等距性。以上控矿模式称为剪应变异常带近等距控矿模式。剪切应变异常带对矿体的控制可能形成于剪切应变异常带形成期的剪切滑动控矿及剪切应变异常带形成之后的微裂隙扩张控矿。将该模式控制的近等距性的矿体进行矿体统计分析预测,有望实现一定的找矿效果。  相似文献   

资源一号02C卫星多光谱数据真彩色模拟技术研究     

王忠武  刘顺喜 《东北测绘》2014,(1):13-16

资源一号02C卫星多光谱数据没有蓝色波段,给制作真彩色影像带来了一定困难。本文针对02C卫星多光谱波段的特点,分析了常用线性模拟蓝波段影像方法,选取多景不同时相的、覆盖山地或平地的真实数据进行加权法和平均值法的对比试验,定性与定量分析后的结果表明：基于加权法生成蓝波段的真彩色模拟结果,无论是从整体色调方面,还是从典型地类的颜色方面,均优于基于平均值法生成蓝波段的真彩色模拟结果,可进一步深入研究后进行规模化应用。  相似文献   

Characterization of spatial and temporal variation of suspended sediments in the Yellow and East China Seas using satellite ocean color data     

SeungHyun Son  Yong Hoon Kim  Hae-Cheol Kim  Kwang-Soon Park 《地理信息系统科学与遥感》2014,51(2):212-226

Total suspended sediment (TSS) data concentrations are retrieved from two sets of satellite ocean color data (the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua and the Korean Geostationary Ocean Color Imager (GOCI)) using an existing regional model to characterize spatial and temporal variation of TSS in the Yellow and East China Seas. MODIS-derived TSS maps show that TSS concentrations are, in general, high along the Korean and Chinese coasts including the Bohai Sea and the Yangtz River estuary, and lower in the middle of the Yellow Sea and the southeastern area of the East China Sea. The monthly average of 10-year MODIS data reveals that TSS values are highest during winter (January to February) and lowest in summer (July to August). Short-term TSS concentrations retrieved from GOCI data showed the dominant influence of semi-diurnal tidal changes on sediment dynamics through temporal (hourly) and spatial distribution in coastal zones of the Yellow sea. The results presented here demonstrate that the satellite-derived TSS products can be utilized as an application tool for future studies on long- and short-term sediment dynamics of turbid coastal waters. In particular, GOCI observations provide unique important capabilities to characterize and quantify the water properties at high temporal (hourly) and spatial (0.5 km) resolutions in the turbid coastal waters of the Yellow Sea and its vicinities.  相似文献   

颜色和形态学在交通标志识别中的应用研究     

姜雪宁  万幼川  何培培 《测绘与空间地理信息》2014,(12)

从自然场景中识别出交通标志是智能交通系统中的一个重要问题,本文提出了一种基于颜色和形态学的交通标志识别方法.该方法在HSV彩色空间进行颜色阈值分割,并采用形态学重构提取目标区域.再通过标记法检测目标区域形状,检测出交通标志.最后,利用SIFT算法进行模板匹配,识别出交通标志.实验证明,该方法在识别正确率和运行效率上具有明显优势.  相似文献   

双波长卫星激光测距     

张忠萍  李人东  杨福民  扈荆夫 《天文学进展》2005,23(2):99-109

双波长卫星激光测距不必借助大气改正模型，利用双波长往返时间差就可以进行大气折射改正，采用皮秒级事件计时器等技术测量往返时间差，修正精度可以达到毫米量级，介绍了这一领域的研究进展、双波长大气改正的基本原理，分析了双波长激光测距的精度，最后对双波长卫星激光测距前景进行了展望。  相似文献   

火成岩岩石薄片智能识别及分类方法     

曹蒙  王志章  李冰涛  曲康  裴升杰  贾小玉 《地质论评》2023,69(2):2023020001-2023020001

在油气勘探、评价及开发中,岩性识别和薄片鉴定是十分重要的基础工作,准确的薄片识别结果可以为勘探和开发提供可靠的依据。传统的人工判定方法或实验室分析方法具有主观性强、效率低、自动化程度低等问题。目前基于内容的智能图像识别技术在准确性和具体应用方面还面临着许多难题。论文基于国内外相关研究成果与油气勘探与开发中岩芯薄片图像的特点及要求,设计并研制成功薄片图像自动识别系统和薄片智能鉴定系统。利用图像梯度分布和色彩分析进行火成岩岩石薄片智能分类,对所有像素进行类别划分进而得到整体的鉴定结果,实现了省时、高效、高精度的薄片智能鉴定成果。  相似文献   

基于红绿色觉异常人群的路况地图色彩设计研究     

朱海红  夏梦 《测绘工程》2015,(12):1-6

红绿色觉异常人群对于明度变化的感受比正常视觉者更加敏感,可以弥补色相辨别的缺陷。通过针对黄色明度对比实验得出红绿色觉异常人群对明度对比各等级的视觉感受,找出对红绿色觉异常人群既可以容易识别又不会觉得刺眼的明度对比范围。实验结果引入地图设色,结合色彩象征意义,做出红绿色觉异常人群和正常人群通用的路况地图。在路况信息清晰表达前提下,尽可能保留色彩象征意义,并保证地图的观赏性。通过路况地图色彩明度对比实验制作出红绿色觉异常人群既能无障碍识别又带有警示象征意义的路况地图。  相似文献