弱辐射特征遥感影像的自动伽马校正

为了有效地消除光照不均对成像效果的影响,还原原始图像信息,通过分析Gamma校正函数及对函数包含参数的适应性实验,研究并提出了依据原始图像像素分布自动确定Gamma函数参数值的伽马校正方法,实现了弱辐射特征图像的自动灰度修正。对近海区域的遥感影像进行了辐射校正实验,证明该方法对弱辐射特征的遥感影像有很好的校正效果。     

珠江口二类水体MODIS 数据大气校正

以珠江口海域为主要研究区域,针对近岸二类水体近红外波段离水辐射为0的假设不再成立,导致MODIS标准大气校正算法中用于大气校正的两个近红外波段的气溶胶散射值的高估,引起可见光波段离水辐射值较实际值偏小,甚至出现负值的问题,研究了748,869 nm波段的气溶胶散射及离水辐射之间的关系,提出了珠江口二类水体MODIS数据的大气校正算法。通过与MODIS数据标准大气校正算法、基于短波波段的二类水体MODIS数据大气校正算法相比,表明珠江口二类水体MODIS数据的大气校正算法具有一定的优势。     

沙尘辐射效应对海陆风环流影响的数值试验

本文采用二维中尺度模式,并结合沙尘气溶胶模式研究了当沙尘暴袭击海岸时,沙尘的辐射效应对海陆风环流的强迫作用.结果表明:沙尘的辐射效应对海陆风环流的发展、变化、消亡有着重要的影响,沙尘暴区移到海陆上空不同的位置,沙尘对海陆风环流的辐射强迫作用是不同的.     

面向光学遥感的先进光谱辐射定标技术

辐射定标是光学遥感信息定量化的关键技术之一,它的主要作用体现在(1)在工程研制到在轨运行的全过程中,确定和评估传感器的绝对响应;(2)建立不同平台、不同传感器的辐射量基准,保证相关时间和空间尺度下获得的地球物理数据可以相互比对、转换和融合;(3)通过动态监测,校正传感器的性能衰变,修正大气、照明条件和环境变化等对测量结果的影响,保证测量结果真实反映目标和背景的特征.结合我国空间光学传感器的发展要求,提出了实验室、星上和场地替代辐射定标的实施方案建议.实验室定标的主要作用是建立传感器的输出和已知的、用SI单位表述的入射辐射量之间的定量关系,星上定标能够长期地监测传感器响应的衰变,而场地替代定标可以验证传感器的辐射响应并进行多个传感器的交叉定标.通过这3种独立的定标手段的相互验证和比较,能够有效地提高环境光学遥感信息的定量化水平,保证卫星数据的质量.在综述和比较国内外先进辐射定标技术的基础上,提出采用标准探测器和标准辐射源相融合的辐射定标基本途径,来实现卫星传感器3个阶段的辐射定标,并讨论了技术实现的方案.     

我国海区SeaWiFS资料大气校正

利用光谱辐射传输理论，结合海上同步实测资料，开发出我国海区SeaWiFS资料大气校正模型。经卫星资料处理结果比对，本模型在一类水体，基本消除了412nm和443nm波段离水辐射率小于0的现象；在二类水体，利用临近一类水体的大气条件进行了有效的大气校正；同时建立了670nm,765nm,865nm波段的大气校正模型，这三个面适用于高浓度悬浮泥沙的信息提取。本模型用于处理我国海区的SeaWiFS资料比美国NASA模型更适合我国海区特定的大气和海洋环境，为SeaWiFS资料海洋水色信息提取和我国海洋一号（HY－1）及风云一号（FY－1C）卫星资料的大气校正研究提供了技术基础。     

基于Kongsberg EM多波束的Snippet数据处理方法

多波束声呐记录的海底后向散射片段(Snippet)数据处理成角度响应曲线和地理编码(Mosaic)图像可以 帮助识别海底底质类型和反映地貌形态,这一过程包括辐射校正、角度响应改正(AVG)和几何地理编码,但不同的多波束系统硬件在辐射校正和角度响应改正方法上存在差异且传统处理方法忽略了声呐系统本身的指向性模型随时间变化的事实。以声呐方程为基础,针对Kongsberg EM 多波束系统提出了一套完整的Snippet数据处理流程,并分析了各步骤中存在的可变性,给出了每一步的处理建议,最后将此方法应用于EM2040浅水多波束实测数据,并验证了该方法的有效性和实用性。     

紫外辐射对鱼类及水生无脊椎动物影响的研究进展

全球性的气候变化严重地威胁着自然生态环境间的平衡。在影响生态系统功能的诸多因素中,太阳紫外辐射的增强逐渐成为最受关注的全球性环境问题之一。太阳紫外辐射对地球生物的生命过程有着举足轻重的影响。生物体一旦吸收了高能量的紫外辐射,则可对其各种生理过程产生影响,打破内稳态,尤其是紫外辐射对DNA的损伤作用,是诱导一系列生物效应的主要原因。本文综述了近年来与鱼类及水生无脊椎动物有关的紫外辐射研究。从紫外辐射对生物不同发育时期的影响、生物对紫外线响应方式、紫外辐射与其他因素复合影响三个层面进行总结。通过总结紫外辐射对鱼类及水生无脊椎动物的影响,可为预测紫外辐射在水生生态系统中的作用提供助力,为海洋生物对环境变化的生理响应研究提供参考。     

辐射应力理论在近岸区的应用及其研究进展

概述了波浪辐射应力理论,介绍了波浪辐射应力理论在海洋流体动力学尤其是近岸区的应用,重点分析了该理论在研究近岸波生流、波流相互作用等问题中的应用,总结了波浪辐射应力的研究进展,对辐射应力研究提出了建议。     

垂向变化的波浪辐射应力影响下流场数值研究

采用浪流沙耦合模型COHEREN-SED模型进行黄河三角洲的海流三维运动数值模拟。文中将垂向平均的波浪辐射应力与垂向变化的波浪辐射应力引入至COHERENS-SED,通过该模型进行波浪辐射应力影响下的海流场演变数值研究。研究结果显示波浪辐射应力的存在显著改变了水深小于5m的流场。垂向变化的辐射应力则使得其表层波生沿岸流速大于传统的垂向均匀辐射应力引起的波生沿岸流速,底层则刚好相反。当波浪强度很大时,流场中的波生沿岸流对水深较浅的海岸区海流场影响较大。     

海面微波辐射特性测量与分析

在对海面微波辐射特性现场测量和数据处理的基础上,结合对海面微波辐射理论的初步分析,研究了各种环境参数以及辐射计参数与海洋微波谱特性的相关关系,为海洋微波遥感 资料的分析和解译提供了基础数据。测量结果表明了辐射计参数和环境要素对海面微波辐射特性的影响,而这些影响因素在分析、解译遥感资料时是必需考虑的因素。     

用于遥感测温的双通道红外辐射计

本文介绍了一种用于遥感温度测量的、且与目前大多数星载红外遥感器波段相一致的双通道红外辐射计。该辐射计采用碲镉汞做为探测器。它可用于温度测量,其同步测量数据可用于星载红外遥感器的定标和数据的真实性检验。本文介绍了总体方案、精度计算及光、机、电和数据处理等部分的设计方法。     

基于星载微波辐射计的海洋大气参数反演算法研究

利用3个辐射传输模式对无冰无降水情况下的星载微波辐射计亮温测量进行仿真研究,通过模拟计算结果与同步卫星数据之间的比较分析,确定了用于反演算法研究的前向模式;利用该模式,提出了基于物理的星载微波辐射计海洋大气参数(包括海面风速、海表温度、大气垂直积分水汽量以及积分液态水量)多重线性回归算法。     

Algorithm for the Atmospheric Correction of Shortwave Channels of the MSU-MR Radiometer of the Meteor-M No. 2 Satellite

Izvestiya, Atmospheric and Oceanic Physics - The problem of atmospheric correction for shortwave channels of a multispectral low-resolution scanning radiometer onboard the Meteor-M No. 2 satellite...     

Generation of high resolution sea surface temperature using multi-satellite data for operational oceanography

In the present article, we introduce a high resolution sea surface temperature(SST) product generated daily by Korea Institute of Ocean Science and Technology(KIOST). The SST product is comprised of four sets of data including eight-hour and daily average SST data of 1 km resolution, and is based on the four infrared(IR) satellite SST data acquired by advanced very high resolution radiometer(AVHRR), Moderate Resolution Imaging Spectroradiometer(MODIS), Multifunctional Transport Satellites-2(MTSAT-2) Imager and Meteorological Imager(MI), two microwave radiometer SSTs acquired by Advanced Microwave Scanning Radiometer 2(AMSR2), and Wind SAT with in-situ temperature data. These input satellite and in-situ SST data are merged by using the optimal interpolation(OI) algorithm. The root-mean-square-errors(RMSEs) of satellite and in-situ data are used as a weighting value in the OI algorithm. As a pilot product, four SST data sets were generated daily from January to December 2013. In the comparison between the SSTs measured by moored buoys and the daily mean KIOST SSTs, the estimated RMSE was 0.71°C and the bias value was –0.08°C. The largest RMSE and bias were 0.86 and –0.26°C respectively, observed at a buoy site in the boundary region of warm and cold waters with increased physical variability in the Sea of Japan/East Sea. Other site near the coasts shows a lower RMSE value of 0.60°C than those at the open waters. To investigate the spatial distributions of SST, the Group for High Resolution Sea Surface Temperature(GHRSST) product was used in the comparison of temperature gradients, and it was shown that the KIOST SST product represents well the water mass structures around the Korean Peninsula. The KIOST SST product generated from both satellite and buoy data is expected to make substantial contribution to the Korea Operational Oceanographic System(KOOS) as an input parameter for data assimilation.     

Cosmos-243 as the Starting Point for the Development of Microwave Radiometry Methods of the Earth’s Atmosphere and Surface

On September 23, 1968, the Cosmos-243 satellite was launched into orbit with four radio telescopes directed to the nadir on board. They were designed to measure the microwave radiation of the Earth’s surface and its atmosphere at wavelengths of 0.8, 1.35, 3.4, and 8.5 cm. The onboard infrared radiometer measured radiation in the band of 10–11 µm in the same solid angle as the radio telescopes. This experiment, which was initiated by scientists from the Institute of Radioengineering and Electronics (IRE) and Institute of Atmospheric Physics (IAP) and, in particular, academicians V.A. Kotel’nikov and A.M. Obukhov, broke new ground in the remote sensing of the Earth from space, which is being actively developed.     

A Simple Method to Minimize Orientation Effects in a Profiling Radiometer

Marine optical parameters required for ocean color satellite applications must be measured with high accuracy and errors within the permissible limits. These stringent requirements demand careful measurements of optical parameters. Though the free-fall radiometer is found to be a better option for measuring underwater light parameters as it avoids the effects of ship shadow and is easy to operate, the measurements demand profiling the radiometer vertical in water with minimum tilt. Here we present the results of our observations on the tilts of the radiometer from the measurements in the Arabian Sea. Since there is hardly any study carried-out on the tilt of the profiling radiometer, the result of this study will help in the better design of such marine instruments. The tilt of the radiometer near the surface of the water is attributed to the mode of deployment and environment parameters, while the tilt at depth of the water is influenced by the density variations of the water. Here we also demonstrate a method of deploying the instrument that minimizes the tilt of the instrument at the surface layer of the water.     

Mapping of ice in the Odden by satellite and airborne remote sensing

A detailed analysis of the ice conditions in the Odden area of the Greenland Sea was carried out using data from active and passive microwave sensors, supplemented by airborne data. The study focuses on the 1992–1993 winter season, the only winter during the period 1993–1995 in which an Odden feature formed. The analysis is structured as a hierarchy of spatial resolutions where the overview is obtained by the DMSP SSM/I microwave radiometers having spatial resolutions in the 15–50 km range. Further details in cloud-free situations are obtained by data from the NOAA advanced very high resolution radiometer, which is a scanner in the visible, near-infrared and thermal infrared range with a resolution of 1.1 km. The finest resolution of 25 m per pixel is obtained from the synthetic aperture radar on the ERS-1 satellite.     

Landsat-8 TIRS数据在某核电站温排水监测中应用探讨

为探索Landsat-8 TIRS热红外数据在核电站温排水监测的应用能力,以某核电附近海域为研究区域,采用单窗算法建立核电站附近海域表面温度反演方法,并将该结果与时相接近的MODIS海温产品数据进行了对比分析。结果表明,反演的温度场可较精细地刻画该核电站附近温度场的分布情况,Landsat-8 TIRS数据可实现较高精度的核电站温排水监测。     

Errors in scatterometer-radiometer wind measurement due to rain

An on-board microwave radiometer can correct measurement errors due to rain attenuation for a satellite-borne microwave scatterometer, thereby allowing more accurate determination of the ocean-surface wind vector. In clear weather or when area-extensive homogeneous clouds and rain are present, corrections can be made properly even if the radiometer footprint is much larger than that of the scatterometer. When frontal or cyclonic storms are present, so that the rain and cloud distributions are nonuniform across the footprints, substantial errors remain in the "corrected" scatterometer measurements (in some cases "corrections" actually increase the errors). Simple-geometry simulations are reported here for nonidentical overlapping scatterometer and radiometer footprints with large gradients of attenuation and wind speed. In addition, examples are presented for a hurricane observed by the SEASAT-1 oceanographic satellite. These simulations demonstrate the size of the errors in wind speed (and direction for the hurricane) remaining after "correction." At higher wind speeds, the error is sometimes twice as large as the actual wind speed. The worst errors occur when the scatterometer footprint overlaps two or more radiometer footprints and the attenuation in the scatterometer footprint differs greatly from those in parts of the radiometer footprints. The presence of such large errors is inherent in systems having independent scan patterns for radiometer and scatterometer and having large radiometer footprints. A true radiometer-scatterometer system, having identical coincident footprints comparable in size with typical rain cells, could overcome this problem.     

Wavelet analysis of satellite images for coastal watch

The two-dimensional wavelet transform is a very efficient bandpass filter, which can be used to separate various scales of processes and show their relative phase/location. In this paper, algorithms and techniques for automated detection and tracking of mesoscale features from satellite imagery employing wavelet analysis are developed. The wavelet transform has been applied to satellite images, such as those from synthetic aperture radar (SAR), advanced very-high-resolution radiometer (AVHRR), and coastal zone color scanner (CZCS) for feature extraction. The evolution of mesoscale features such as oil slicks, fronts, eddies, and ship wakes can be tracked by the wavelet analysis using satellite data from repeating paths. Several examples of the wavelet analysis applied to various satellite images demonstrate the feasibility of this technique for coastal monitoring