共查询到20条相似文献，搜索用时 296 毫秒
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用于海洋-大气辐射传递计算的光学参数数据库 总被引：1，自引：1，他引：1
开发和建立了用于海洋-大气辐射传递计算的光学参数数据库.它包括海中主要成分(纯海水、浮游植物、悬移质、可溶有机物)的固有光学参数(光谱吸收系数、光谱散射系数等)及大气中主要气溶胶的有关光学参数.在这些光学参数中,大多数是来自现场的直接测量,一些是间接测量获取,还有一些是通过理论计算得到. 相似文献
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漫衰减系数是一个重要的海洋光学参数,能够为水体环境变化、水质分析以及水产养殖等方面提供基础性数据。针对目前船载实地测量效率与分辨率低、卫星遥感反演精度与分辨率较低的局限性,本文提出一种基于机载LiDAR测深水体波形的漫衰减系数提取方法。该方法首先通过分层异构模型的机载LiDAR波形分解算法得到水体散射回波,利用激光在水体中的衰减特性,构建漫衰减系数提取模型,最终获取大面积水域漫衰减系数的空间分布。采用西沙甘泉岛与江苏连云港两个航次的实测数据对所提算法进行了验证,本算法无需每个测深点的水底底部回波强度和深度即可反演得到漫衰减系数,并且在浑浊水域也可取得较好的效果,表明在中国近海利用机载LiDAR测深系统能够有效获取高精度的漫衰减系数。 相似文献
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黄海、东海上空春季气溶胶光学特性观测分析 总被引：11，自引：5，他引：11
2003年春季国家卫星海洋应用中心等几家单位在黄海和东海海区进行了为期40 d的二类水体信息测量试验,试验中使用手持太阳辐射计对海区上空大气光学特性进行了观测,并获得了大量晴空天气条件下的大气光学数据.利用本次试验获取的测量数据得到了黄海、东海海区春季的大气气溶胶光学特性,其中包括气溶胶光学厚度和气溶胶粒子谱分布.采用Langley方法对测量得到的太阳直射辐射量进行处理得到了海区上空气溶胶光学厚度,利用得到的气溶胶光学厚度来反演气溶胶粒子谱分布.反演结果表明无云情况下黄海、东海上空的气溶胶光学厚度在0.2~0.4左右,且气溶胶粒子谱分布的变化趋势也很接近;海区上空霾层较厚时测量得到的气溶胶光学厚度明显增大,最大接近0.8;气溶胶粒子谱分布的变化趋势发生了明显的变化. 相似文献
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Dispersion of reflectances in air and oil between 400 and 700 nm of a suiteof scolecodont concentrates with known Conodont Alteration Index was determined using a reflected light microscope. Refractive and absorptive indices of these scolecodonts were calculated using their determined reflectances.Morphologically, scolecodonts in carbonate show similar granular morphology to that of graptolites. Fine structural details of scolecodonts can be observed under reflected light.Reflectances, refractive and absorptive indices of scolecodonts at 546 nm increase with increase of the Conodont Alteration Index, indicating that these properties of scolecodonts can be used to determine the maturity of sediments.Dispersion of the optical properties of scolecodonts follows similar trends to those for vitrinite, natural bitumen and graptolites, indicating similar molecular structural changes with increasing maturity. 相似文献
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一种水下激光成像的新方法 总被引：1，自引：0，他引：1
在我国沿海近岸,急需通过激光同步扫描方法建立1套浑水观测系统,解决水下视觉问题。本文研究了激光在水下的传输特性,结合散射光的分布特性,确定同步扫描的光学结构设计,通过对获得的系统各类信号特性的分析,设计合适的成像系统;并从理论和水池试验两方面分别论证了这种系统消除散射影响的有效性;论述了这种系统在浑水中的宽视角场和全景深的优良特性。 相似文献
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Development of atmospheric correction algorithm for Geostationary Ocean Color Imager (GOCI) 总被引：2，自引：0，他引：2
Jae-Hyun Ahn Young-Je Park Joo-Hyung Ryu Boram Lee Im Sang Oh 《Ocean Science Journal》2012,47(3):247-259
This paper describes an atmospheric correction algorithm for Geostationary Ocean Color Imager (GOCI) and its early phase evaluation. This algorithm was implemented in GOCI Data Processing System (GDPS) version 1.1. The algorithm is based on the standard SeaWiFS method, which accounts for multiple scattering effects and partially updated in terms of turbid case-2 water correction, optimized aerosol models, and solar angle correction per slot. For turbid water correction, we used a regional empirical relationship between water reflectance at the red (660 nm) and near infrared bands (745 nm and 865 nm). The relationship was derived from turbid pixels in satellite images after atmospheric correction, and processed using aerosol properties derived for neighboring non-turbid waters. For validation of the GOCI atmospheric correction, we compared our results with in situ measurements of normalized water leaving radiance (nL w ) spectra that were obtained during several cruises in 2011 around Korean peninsula. The match up showed an acceptable result with mean ratio of the GOCI to in situ nL w (??), 1.17, 1.24, 1.26, 1.15, 0.86 and 0.99 at 412 nm, 443 nm, 490 nm, 555 nm, 660 nm and 680 nm, respectively. It is speculated that part of the deviation arose from a lack of vicarious calibration and uncertainties in the above water nLw measurements. 相似文献
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Mnica V. Orellana Timothy W. Petersen Alan H. Diercks Samuel Donohoe Pedro Verdugo Ger van den Engh 《Marine Chemistry》2007,105(3-4):229-239
Dissolved organic matter (DOM) is a major carbon reservoir for the global carbon cycle, and its molecules play a key role in the biogeochemistry of the ocean. Colloidal DOM macromolecules assemble to form polymer hydrogels known as marine microgels. Marine microgels represent one of the most dynamic pools of organic carbon in the ocean. However, their optical characteristics and their contribution to ocean optical properties are largely unknown. In this work, we explore the optical and proteomic properties of spontaneously assembled DOM polymer microgels. Microgels from cultures and from Puget Sound seawater were sorted and counted using a dual-laser (365 nm/365 nm) high-speed cell sorter. This sorter has been adapted to interface with a scanning monochromator to measure the fluorescence emission spectrum of the microgels over the range from 300 to 850 nm. Surprisingly, the microgels show a broad fluorescence emission from 420 to 520 nm when excited with UV light. The microgels were classified according to their blue autofluorescence, and by three criteria that are used to define microgels: 1) staining with chlortetracycline 2) the ability to undergo phase transitions at low pH, and 3) dispersion following calcium chelation by EDTA. 相似文献
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Zexia Qiu Hangzhou Wang Tao Li Hong Song Yuanqian Wu Tingting Yan Ying Chen 《海洋学报(英文版)》2021,40(3):134-141
An irradiance profile measurement approach and profiling system were developed to measure the solar irradiance profile of the Arctic sea ice using fiber optic spectrometry. The approach involved using a miniature spectrometer to sense light signals collected and transmitted from a fiber probe. The fiber probe was small, and could thus move freely in inclined bore holes drilled in sea ice with its optical entrance pointing upward. The input-output relationship of the system was analyzed and built. Influence factors that determined the system output were analyzed. A correctional system output approach was proposed to correct the influence of these factors, and to obtain the solar irradiance profile based on the measurements outputted by this system. The overall performance of the system was examined in two ice floes in the Arctic during the 9 th Chinese National Arctic Research Expedition. The measured solar irradiance profiles were in good agreement with those obtained using other commercially available oceanographic radiometers. The derived apparent optical properties of sea ice were comparable to those of similar sea ice measured by other optical instruments. 相似文献
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It is shown that an optical beam-attenuance meter integrated into an Aanderaa current meter is a suitable device for measuring time series of fluxes of suspended material in turbid estuarine water. Some typical applications are presented. 相似文献
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Waters along China coast are very turbid with high concentrations of suspended sediment nearly all the time,especially at the Hangzhou Bay,the Changjiang (Yangtze) River Estuary and the shoal along Jiangsu Province.In these turbid and optically complex waters,the standard MODIS ocean color products tend to have invalid values.Because the water-leaving radiances in the near-infrared (NIR) are significant resulting from the strong scattering of suspended particles,the standard MODIS atmospheric correction algorithm often gets no results or produces significant errors.And because of the complex water optical properties,the OC3 model used in the standard MODIS data processing tends to get extremely high chlorophyll-a (Chl-a) concentrations.In this paper,we present an atmospheric correction approach using MODIS short wave infrared (SWIR) bands based on the fact that water-leaving radiances are negligible in the SWIR region because of the extreme strong absorption of water even in turbid waters.A regional Chl-a concentration estimation model is also constructed for MODIS from in situ data.These algorithms are applied to MODIS Aqua data processing in the China coastal regions.In situ data collected in the Yellow Sea and the East China Sea in spring and autumn,2003 are used to validate the performance.Reasonably good results have been obtained.It is noted that water-leaving reflectance in the NIR bands are significant in waters along the China coast with high sediment loadings.The satellite derived and in-situ reflectance spectra can match in the turbid waters along China coast,and there is relatively good linear relationship between satellite derived and in-situ reflectance.The RMSE value of Rrs(λ) is 0.0031 sr ?1 for all the nine ocean color bands (412 to 869 nm).The satellite-derived Chl-a value is in the reasonable range and the root mean square percentage difference is 46.1%. 相似文献
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黄海、东海海区水体散射特性研究 总被引：32，自引：0，他引：32
半分析模型是水色遥感反演算法的研究热点,而水体后向散射系数对建立半分析水色反演模型是非常重要的参数.通过对黄海、东海海区的水体固有光学量测量数据进行分析,得到水体总后向散射系数与水体总散射系数的关系为乘幂关系,颗粒物后向散射系数随光谱变化的指数在高低浑浊度水体有很大差异,并初步得到黄海、东海海区水体的后向散射系数与总悬浮物浓度的关系,从而为水色半分析模型建立和水光学辐射计算提供一组散射特性模型. 相似文献
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An Nd:YAG-based airborne lidar system has been used to measure the optical properties of littoral waters off the northwest Scottish coast. The small-scale structure of subsurface scattering layers was also investigated. Methods of solving the Lidar Sensing Equation in the single scattering approximation are described and the values of the derived extinction indices presented. The extinction index averaged over a series of five flights to the northeast of the Gulf Stream was k = 0.224 m -1 with a standard deviation of 0.212 m -1 . Further, it was demonstrated that, in coastal waters, optical inhomogeneities with dimensions between 50 m and 200 km obey the power law Sp k ~ k -P with the parameter P close to two. In turbid or transparent areas, the water extinction index can change by several tenths of a percent with respect to the surrounding water mass. This suggests that the observed nonmonotonic behavior of the power spectra of the water extinction index fluctuations is caused by the outer scale of turbulence, in particular, by the bottom depth at the measurement site. 相似文献
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The optical coefficients of soot particles are measured in a flow-through optical cell at the wavelength 635 nm in a dry atmosphere and in an atmosphere saturated with water vapor. Two types of systems modeling atmospheric soot aerosols and differing in the degree of hygroscopicity of their particles are investigated and compared. One of the systems contains hydrophobic acetylene soot, and the other contains hydrophilic soot obtained through modification of the initial soot by vapors of glutaric acid. The results show that the optical properties of hydrophobic soot depend only slightly on the conditions of moistening, whereas the optical properties of hydrophilic soot change abruptly upon its moistening because of the formation of a hydrate shell. In the atmosphere saturated with water-vapor, the monomolecular layer of a hydrophilic organic substance leads to the watering of particles and an abrupt (more than twofold) increase in the cross section of light scattering. A further growth of the hydrophilic component of soot particles initiates the formation of micron drops on them, thus resulting not only in the natural effect of light scattering enhancement but also in a noticeable light absorption increase. In particular, a light absorption enhancement by a factor of 3.5 is characteristic of particles of enriched hydrophilic soot. 相似文献