信息影像的应用（中）

6 气象卫星信息影像的应用气象卫星获取的信息影像,卓有成效地应用于天气预报、灾害天气预警及全球性气候变化研究,作为一种遥感信息源,备受青睐,长盛不衰。气象卫星家族包括与地球自转同步的“静止”气象卫星和与太阳同步的极轨气象卫星。分别位于36000km和 600～1400 km的高度。前者可覆盖全球北纬60°到南纬60°之间的地区,24小时可对地观     

中国近海卫星测高数据的重力异常反演—— I. Stokes公式逆运算+2D FFT法

简要介绍了基于Stokes公式逆运算基础上的重力异常FFT反演方法。据此 ,在对 4年的Topex/Poseidon卫星测高数据和一年半的ERS 1/ 35天卫星测高数据的预处理基础上 ,反演了中国海域 (0°～ 4 0°N ,10 5°～ 135°E)的 30′× 30′重力异常———IGG。通过与实际船测资料和国际同行提供的重力模型相比 ,IGG总体精度达到 10× 10 - 5m/s2 。     

空间辐射致冷器的热平衡计算和分析

一、引言侦察卫星、预警卫星、气象卫星、资源探测卫星等都要使用多光谱遥感探测仪器。在红外波段使用的红外探测器必须在低温下工作以提高其灵敏度、缩短响应时间、拉宽响应波长范围、降低本底噪声。例如,碲镉汞探测器要冷却到80～100K;工作波长8～12微米的锗掺汞探测器要在30K 左右的低温下工作。     

新拌混凝土的力学特性

本文作者使用了一台可三向加压的设备对新拌混凝土的剪切强度作了研究。采用的试捧直径100mm、高200mm,试验温度为21℃及4℃,试捧放置时间为40～160min。对每一时间与温度组合特性下其试验结果都用莫尔—库仑(Mohr-Coulomb)及罗尔(Ro-we)的剪切强度理论进行分析。在拌合稳定及存在10%的变形破坏条件下,前者得出内摩擦角的值为37°～41°而后者为18°～21°。这两种理论都表明新拌混凝土的聚合力最初为零,而随着放置时间的增长而增加。     

南黄海辐射沙洲附近海域悬浮泥沙的遥感反演研究

利用2003年实测的悬浮体样品和遥感反射率数据以及美国NOAA气象卫星AVHRR数据的可见光波段,进行了南黄海辐射沙洲附近海域悬浮泥沙的遥感反演研究.结果发现:悬沙浓度和实测遥感反射率之间存在很好的线性关系(R2=0.9537, n=39),利用该关系式进行该区悬沙遥感反演取得了较好的结果.遥感反演证明,研究区悬沙浓度值由高至低从沙洲中部向沙洲周围延伸;悬沙的分布呈现出明显的季节性,秋季悬沙浓度值一般为春季的1/5;且秋季悬沙的平面扩散范围要小于春季的扩散范围.以上研究结果可为我国海岸带泥沙实时监测和悬浮泥沙遥感定量研究提供必要的基础资料.     

我国新一代极轨气象卫星（风云三号） 工程地面应用系统

风云三号气象卫星是实现全球、全天候、多光谱、三维、定量遥感的我国第二代极轨气象卫星系列,已成为世界气象组织在亚洲的重要业务卫星,为提高我国气象卫星在世界气象组织卫星观测系统中的地位奠定了重要的基础,世界气象组织已将风云三号气象卫星纳入世界气象卫星全球观测业务序列。依靠我国自主力量设计与建设的新一代极轨气象卫星风云三号地面应用系统首次利用海内外接收站网实现了上、下午星全球资料的高时效获取,首次利用国产卫星实现了大气三维探测,实现了臭氧和辐射收支等探测的高精度处理,突破了卫星资料定量反演、数值预报同化应用以及气候应用等核心技术。     

平面波入射假设引起的方位向极化SAR数据校正

在雷达波束照射区域内 ,由于实际波束为球面波 ,使每个象素对应于不同的入射角。在成像数据处理过程中 ,人们将入射波视为平面波 ,将所有象素对应的入射角近似为雷达视角。为了对平面波入射假设引起的方位向极化合成孔径雷达 (POLSAR)数据进行校正 ,本文提出POLSAR数据校正因子 ,并推导出校正因子表达式。数值结果表明 :校正因子可以被近似为实数。当雷达视角小于 4 0°～ 4 5°时 ,校正因子随雷达视角的增大而变小 ,当雷达视角大于 4 0°～ 4 5°时 ,校正因子随雷达视角的增大而变大。结果还表明 ,雷达视角范围为 10°～ 4 0°效果较为理想     

一种高温测量电路

在诸多种类的温度测量中,本文所阐述的温度测量电路具有较广泛的实用性,电路简洁、明了,有较高的测量精度和较强的抗干扰能力。 原理电路图 图指的电路是根据白噪声公式: E_n=(4KTRB)~(1/2)来测量温度,可测得的温度范围是10°K～2500°K并且有0.1°K的精度。     

液氖的制取和应用

为了获得极低温,除液氢(冷至14—30°K)和液氦(冷至1.5—5°K)之外可使用惰性液氖,它能使温度达到24—43°K的范围。下面列出作为致冷剂的氖、氢和氦的物理性能:     

东海区海表温度与中上层渔获量关系的时空分析

从GIS的空间分析的角度研究渔业产量同海洋环境要素的关系 ,结合东海区( 118.5°～ 130°E ,2 4°～ 36°N) 1987～ 1998年的海表温度场及同期的中上层鱼类的渔获量数据 ,定量地刻划出温度场与温度梯度场分别与渔捞量之间关系 ,并进一步寻找渔场同环境要素之间关系的空间变化规律     

星载遥感器的可见和近红外波段的绝对定标

在洁净海洋上空,卫星遥感器在可我谱区中接收到的信号主要来自于大气分子 射,根据大气辐射传输机理利用观测海洋的方法,对星载遥感器的可见和近红外通道进行绝对辐射定标。为了克服大气气溶胶散射对辐射定标 影响,利用组合可见和近红外通道同时观测高亮云层和洁净海面对ＮＯＡＡ－１４ ＡＶＨＲＲ作出了精确的辐射定标。     

可见光和热红外辐射定标方法浅述

随着遥感技术的发展，遥感影像的应用越来越为人们所关注。而遥感影像的处理成为不可缺少的关键环节。在遥感数据的采集过程中，由于受到仪器本身的误差及自然环境诸多因素的影响，不可避免的产生种种误差。为了获得真实反映地物信息的图像，必须进行纠正。本详细介绍了引起辐射畸变的因素以及各种辐射纠正的方法，并以NOAA为例详细分析了其产生畸变的原因，并着重介绍了三种辐射定标方法：反射率法、辐亮度基法和辐照度基法，结果显示辐照度基法较为理想。     

Satellite-to-satellite tracking and satellite gravity gradiometry (Advanced techniques for high-resolution geopotential field determination)

The purpose of satellite-to-satellite tracking (SST) and/or satellite gravity gradiometry (SGG) is to determine the gravitational field on and outside the Earth's surface from given gradients of the gravitational potential and/or the gravitational field at satellite altitude. In this paper both satellite techniques are analysed and characterized from a mathematical point of view. Uniqueness results are formulated. The justification is given for approximating the external gravitational field by finite linear combination of certain gradient fields (for example, gradient fields of single-poles or multi-poles) consistent to a given set of SGG and/or SST data. A strategy of modelling the gravitational field from satellite data within a multiscale concept is described; illustrations based on the EGM96 model are given.     

金枪鱼渔场分析预报模型及系统的开发

以收集到的卫星遥感反演海表温度和金枪鱼历史捕捞产量资料为基础,统计建立了金枪鱼渔场的贝叶斯概率预报模型.以实现金枪鱼渔场预报为目标,采用控件式地理信息系统(GIS)技术,成功开发了大洋金枪鱼渔场的分析预报系统.对历史数据进行了模型回报试验,试验结果表明,金枪鱼渔场综合预报的准确性达到70%以上,渔场示范试验预报准确性也达到60%以上,对渔业捕捞生产具有一定的指导意义.     

Assessment of a bidirectional reflectance distribution correction of above-water and satellite water-leaving radiance in coastal waters

Water-leaving radiances, retrieved from in situ or satellite measurements, need to be corrected for the bidirectional properties of the measured light in order to standardize the data and make them comparable with each other. The current operational algorithm for the correction of bidirectional effects from the satellite ocean color data is optimized for typical oceanic waters. However, versions of bidirectional reflectance correction algorithms specifically tuned for typical coastal waters and other case 2 conditions are particularly needed to improve the overall quality of those data. In order to analyze the bidirectional reflectance distribution function (BRDF) of case 2 waters, a dataset of typical remote sensing reflectances was generated through radiative transfer simulations for a large range of viewing and illumination geometries. Based on this simulated dataset, a case 2 water focused remote sensing reflectance model is proposed to correct above-water and satellite water-leaving radiance data for bidirectional effects. The proposed model is first validated with a one year time series of in situ above-water measurements acquired by collocated multispectral and hyperspectral radiometers, which have different viewing geometries installed at the Long Island Sound Coastal Observatory (LISCO). Match-ups and intercomparisons performed on these concurrent measurements show that the proposed algorithm outperforms the algorithm currently in use at all wavelengths, with average improvement of 2.4% over the spectral range. LISCO's time series data have also been used to evaluate improvements in match-up comparisons of Moderate Resolution Imaging Spectroradiometer satellite data when the proposed BRDF correction is used in lieu of the current algorithm. It is shown that the discrepancies between coincident in-situ sea-based and satellite data decreased by 3.15% with the use of the proposed algorithm. This confirms the advantages of the proposed model over the current one, demonstrating the need for a specific case 2 water BRDF correction algorithm as well as the feasibility of enhancing performance of current and future satellite ocean color remote sensing missions for monitoring of typical coastal waters.     

以心率为指标的动态生理分析软件的设计

通过开发出集动态心率分析、体力疲劳状况分析和体力劳动强度分析为一体的动态心率分析软件系统，从而使对被测人员的动态心率分析、体力疲劳程度分级和体力劳动强度分级变得简便易行。该软件在Ｗｉｎｄｏｗｓ９５环境下采用Ｖｉｓｕａｌ Ｂａｓｉｃ５．０语言及Ａｃｃｅｓｓ数据库编制而成，具有功能强、界面美观、操作方便和运行可靠稳定等特点，是一套较为理想的生理分析软件。     

Thermal and stress studies of normal incidence Mo/B4C multilayers for a 6.7 nm wavelength

Wavelength, reflectance, and stress stability of Mo/B(4)C multilayers were studied as a function of postdeposition annealing up to 900 °C. These multilayers are of interest as normal incidence coatings for wavelengths above the boron K-absorption edge. Mo/B(4)C multilayers deposited at low sputtering pressure have high compressive stress. Zero stress can be achieved at 360 °C-370 °C, but annealing at <200 °C is sufficient to reduce stress by ～40%. This stress relaxation is accompanied with a multilayer period expansion of ～0.02 nm and a <0.5% decrease in normal incidence reflectivity. The multilayer period remains stable up to ～600 °C, while intrinsic stress changes from compressive to tensile. A four-layer model with amorphous molybdenum and boron carbide layers separated by amorphous layers of molybdenum borides (Mo(x)B(y)) is presented. These interlayers are present already in the as-deposited state and continue to grow with increasing temperature. Their presence lowers the optical contrast and the achievable reflectivity. However, they also increase multilayer thermal stability. At temperatures >600 °C, a noticeable decrease in reflectivity associated with the phase transition from amorphous to crystalline molybdenum boride is observed. This is accompanied with an increase in interface and surface roughness and a change in stress as a function of temperature.     

Snow-melt run-off studies using remote sensing data

Snow-covered area (SCA) is a critical input in snow-melt run-off studies. It is difficult to get timely information about SCA, especially of mountain watersheds, by conventional survey methods, including aerial surveys. With the advent of satellite remote sensing, it has now become possible to obtain reliable and regular SCA data. This has led to the development of snow-melt run-off simulation and forecasting models using SCA derived from LANDSAT and NOAA data; the models in use in USA and India are described.     

Workshop on Bridging Satellite Climate Data Gaps

Detecting the small signals of climate change for the most essential climate variables requires that satellite sensors make highly accurate and consistent measurements. Data gaps in the time series (such as gaps resulting from launch delay or failure) and inconsistencies in radiometric scales between satellites undermine the credibility of fundamental climate data records, and can lead to erroneous analysis in climate change detection. To address these issues, leading experts in Earth observations from National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Adminstration (NOAA), United States Geological Survey (USGS), and academia assembled at the National Institute of Standards and Technology on December 10, 2009 for a workshop to prioritize strategies for bridging and mitigating data gaps in the climate record. This paper summarizes the priorities for ensuring data continuity of variables relevant to climate change in the areas of atmosphere, land, and ocean measurements and the recommendations made at the workshop for overcoming planned and unplanned gaps in the climate record.