基于WebGIS的TB级南极遥感影像发布系统关键技术研究

我国已经完成南极地区多种类型高分辨率遥感影像的制图,其产品的数据量达到TB级,对这些影像进行网络共享有助于帮助人们更好地认识南极,也能提升我国在南极事务中的影响力.本文介绍了基于数据库以及WebGIS平台的TB级南极洲遥感影像图网络发布系统的设计与实现方法.以ArcGIS Server作为WebGIS平台,对各类遥感影...     

ETM+遥感地质普查中构造解译与应用

通过ERDAS软件对ETM+影像进行处理,以成矿理论为指导,通过分析和研究黄田地区遥感影像的线性、环形构造,发现研究区内已知的主要矿化集中地基本分布于密集的线性、环形构造影像的交汇部位。     

极地记录冰川和达尔克冰川流速的遥感监测研究

测定南极冰川的流速 ,对于研究南极冰雪物质平衡、南极环境变化及其对全球环境的影响有重大意义。本文论述了利用多时相卫星遥感影像监测冰川变化的原理和方法 ,通过对英格里特 .克里斯泰森海岸不同时期的遥感影像进行几何纠正和配准及叠加处理 ,测量和计算出极地记录冰川和达尔克冰川的平均流速 ,并对它们的变化特点进行了初步的分析和评价。     

基于粗阈值和梯度算法的南极多光谱影像云区的提取

利用Landsat-7的ETM+多光谱影像,提出使用粗阈值以及梯度算法提取极地上空的云。试验结果表明,粗阈值增加了阈值算法的灵活性,并结合梯度算法,由粗到精,达到了较好的极地目标识别效果。     

改进HOT的高分影像自动去薄云算法

为了有效去除薄云对高分光学影像造成的干扰,解决传统算法自动化程度低、去薄云效果不理想的问题,提出改进的薄云最优化变换(Improved Haze-Optimized Transformation,IHOT)算法。首先采用暗原色先验知识从薄云影像中自动选取晴空区,运用薄云最优化变换检测薄云,再创新性地利用植被区域云检测精度较高的特点改进检测结果,最终使用虚拟云点法进行薄云去除。利用高分一号影像进行实验,证明该文提出的算法能够有效地去除薄云对高分影像的影响,尤其对人造地物的色彩和纹理信息恢复效果优于传统算法。     

粤东北地区ETM+遥感图像处理及信息提取

以粤东北地区为研究对象,通过辐射定标、低通滤波处理、分辨率融合、几何校正等处理,对ETM+影像的光谱信息进行综合分析。提取断裂构造信息,以提高该区地质认识并指导下一步地质工作的目的。     

南极中山站地区太阳辐射的某些特征分析

本文根据1990年1～2月南极中山站的太阳辐射的首次观测数据,分析了该地区太阳分光辐射的变化特征,着重讨论了紫外辐射的变化特征和云对太阳辐射各分量的影响。结果表明,南极中山站地区晴天条件下可见光、近红外和紫外辐射占总辐射的42.2％、53.3％和4.5％;总云量的变化和云类的变化对太阳辐射各分量具有显著的影响。     

南极地区常用地图投影及其应用

南极地区常用的地图投影方式有 :极方位立体投影、横轴墨卡托投影、兰伯特正形圆锥投影等三种等角投影。本文在介绍了所有等角投影应满足的一般条件的基础上 ,分别详述了上述三种投影在南极地区的具体应用。并对卫星影像的投影作了探讨。     

近30年南极海冰的变化特征

采用NCEP的1973-2002年南极海冰密集度资料,对近30年南极海冰冰密集度的季节变化、年际变化及其与南极海冰涛动指数的长期变化关系进行了分析研究。结果表明,南极海冰的季节变化特点是海冰融化速度远大于凝结速度,而北极海冰融化速度与凝结速度基本相同。南极海冰存在着明显的年际变化,海冰面积指数呈增加趋势,年平均倾向率为28/10a。而北极海冰年际变化则相反,呈减少趋势,年平均面积指数的倾向率-3.5/10a。南极海冰涛动指数能代表南极地区近1/3的海水变化,是南极海冰变化的重要指数,具有10年、3-5年和2年左右的准振荡周期。     

内蒙古呼伦贝尔草原湖泊变化研究

内蒙古呼伦贝尔地区湖泊数量多,面积大,占内蒙古湖泊总面积的58％.近年来该地区湖泊趋于萎缩,但是已有研究主要关注大型湖泊,缺乏对该地区湖泊整体,尤其是小型湖泊(<1 km2)的研究.通过利用Landsat系列(TM、ETM+、OLI)卫星数据,参照该地区湖泊图集、湖泊名录以及Google Earth高清影像,分析了19...     

Trends in cloud amount and radiative fluxes at Syowa Station,Antarctica

Variations of cloud amount and radiative fluxes are a matter of discussion related to the recent climate change in the Arctic and Antarctic. It is also of great concern related to “from dimming to brightening” recently found. Discussions based on satellite data had been conducted; however, no solid results are obtained from the surface station data for a long term in the recent.At Syowa Station, Antarctica, meteorological observation has been continued for nearly 50 years. During this term, an annual mean cloud amount showed a gradual increase at a rate of 0.014/yr. Radiation budget was observed since 1991 as one of the BSRN stations. Trends of monthly mean radiative fluxes were compared with those of cloud amount and conformable relations were seen during the period from 1991 to 2004. A cloud radiative forcing was estimated. In December, a downward trend in net longwave and net total appeared, while an upward trend in net shortwave was seen, and all corresponded to the decrease of cloud amount in this month. On the other hand in June, an upward trend in net longwave forcing was seen, corresponding to the increase of cloud amount. On an average, cloud radiative forcings at Syowa Station represented those of Antarctic costal stations near sea ice area.     

东南极普里兹湾1990年1—2月大风过程与气旋和锋面活动分析

本文用澳大利亚墨尔本气象中心,苏联南极青年站地面天气图和NOAA-10,NOAA-11极轨卫星云图确定了东南极普里兹湾及其附近海域1990年1—2月份气旋中心位置;讨论了这些气旋的活动特征。分析了实测大风对应的天气系统,天气形势和卫星云图特征,指出普里兹湾沿海存在气旋、锋面以及锋面云和气旋先后相继的影响。锋面及锋面、气旋先后相继影响与500hPa上的强高压脊天气形势、强风与锋面带中纹理非常不均匀区域有密切关系。     

Development of a cloud detection method from whole-sky color images

A method is proposed for detecting clouds from whole-sky color images obtained with an all-sky camera (ASC) system. In polar regions, cloud detection using whole-sky images usually suffers from large uncertainties in fractional cloud cover retrievals because of large solar zenith angles (SZAs) and high surface albedo, which cause “whitening” in the images. These problems are addressed by using differences between real images and virtual clear-sky images for a particular observation time with the same SZA. The method is applied to ASC images obtained at Ny-Ålesund, Svalbard in May of 2005–2007, and the results are compared with Micro-Pulse Lidar (MPL) measurements. When no clouds were detected by MPL, the false cloud detection rate from ASC classification was 2.1% in total hours. Conversely, when clouds were detected by MPL, the ASC classification underestimated the clouds by 11.6%. In most cases, this occurred when MPL detected very optically thin clouds. Furthermore, the variability of cloud fractions estimated by MPL and ASC was roughly constant regardless of the SZA. Thus, it is confirmed that the method developed in this study is valid for cloud detection from whole-sky color images.     

Estimation of Surface Temperature and Rainfall in Ghana

Geografisk Tidsskrift, Danish Journal of Geography 97: 76–85, 1997.

Daily Meteosat images for 1989 have been analysed for the purpose of mapping surface temperature and rainfall in Ghana. The images in the time-series are georeferenced and the maximum value composite (MVC) technique is applied to the temperature calibrated IR-channel images after a cloud screening of the images. The cloud covered areas are outlined and traced using the Meteosat visible channels. Stratiform clouds are detected using surface albedo while cumuliform clouds are detected based on a technique calculating the spatial variability within a 5 pixel by 5 pixel window around each point in the image. The cloud covered parts of the scene are then delimitated by comparing the normal albedo values and the spatial variance in albedo.

The paper then discusses how the outlined procedure can be applied in an environmental monitoring context. For each of the months June to November 1989 the mean monthly rainfall amounts at 35 meteorological stations are plotted against the mean surface temperature. It is found that apart from the month of June statistical significant linear relationships are obtained and that the scattering around the line is decreasing for increasing sampling length.     

基于卫星热红外辐射信息的新疆强震震例分析

利用NOAA-14极轨气象卫星红外波段的探测数据,对遥感数据进行多种处理,采用影像目视解释和提取地表辐射亮温值的方法,对新疆的三次强震进行分析,结果发现在地震前都出现了热红外异常,这为地震监测提供了一个重要信息。     

1993年中山站地区“臭氧洞”和UV┐B的特征分析

本文给出了１９９３年在东南极中山站（６９．３８°Ｓ，７６．３７°Ｅ）地区首次运用ＷＭＯ（世界气象组织）认可的Ｂｒｅｗｅｒ臭氧分光光谱仪，进行臭氧和ＵＶ－Ｂ地面的同步观测结果。观测表明中山站地区在１９９３年８月初到１１月底频繁出现臭氧低于２００ＤＵ的值；１２月初臭氧值恢复正常。在整个“臭氧洞”期间，臭氧值起伏变化很大，并且和７０ｈＰａ到５０ｈＰａ上空的温度变化密切相关，臭氧的日变化不很明显。中午时刻有生物效应的ＵＶ－Ｂ辐射通量与臭氧斜程柱总量呈负指数关系；云和太阳高度角控制着ＵＶ－Ｂ辐射通量日变化过程。ＵＶ－Ｂ光谱扫描的结果表明２９５－３２５ｎｍ波段内的光谱强度比３１５－３２５ｎｍ的光谱强度更受臭氧变化的影响。消除云和气溶胶对ＵＶ－Ｂ辐射过程的部分影响，对每天中午时刻３００．５ｎｍ和３２３．５ｎｍ光谱强度比值计算，反映出了“臭氧洞”期间臭氧值降低是ＵＶ－Ｂ辐射增强的重要因子。     

Extracting fair-weather data from atmospheric electric-field observations at Syowa Station, Antarctica

At Syowa Station (69.0°S, 39.6°E), located on East Ongul Island near the continent of Antarctica, atmospheric electric-field observations started in 1968 and had been carried out intermittently. An improved electric-field mill at Syowa Station had and obtained better-quality atmospheric electric-field data from February 2005 to January 2006. After a 1-year interruption, the observations resumed in January 2007.The atmospheric electric-field data from Syowa Station are often contaminated due to local disturbances caused by near-ground meteorological phenomena. We examined correlations between the atmospheric electric field and near-ground weather from February 2005 to January 2006 and from February 2007 to January 2008, and proposed a criterion to extract “fair-weather” electric-field data based on wind speed and cloud coverage data. The diurnal variation of fair-weather data in January followed the shape of the so-called Carnegie curve. Fair-weather data obtained during a substorm showed some correspondence between the atmospheric electric field and variations in the geomagnetic field. This newly developed extraction method may enable the use of atmospheric electric-field data for studying the solar terrestrial environment.     

Environmental magnetic measurements of marine sediments from Antarctica: implications to paleoclimate changes during the past 15 ka

ＥｎｖｉｒｏｎｍｅｎｔａｌｍａｇｎｅｔｉｃｍｅａｓｕｒｅｍｅｎｔｓｏｆｍａｒｉｎｅｓｅｄｉｍｅｎｔｓｆｒｏｍＡｎｔａｒｃｔｉｃａ：ｉｍｐｌｉｃａｔｉｏｎｓｔｏｐａｌｅｏｃｌｉｍａｔｅｃｈａｎｇｅｓｄｕｒｉｎｇｔｈｅｐａｓｔ１５ｋａＨｏｕＨｏｎｇｍｉ...