城市绿地景观卫星遥感信息解译——以上海市为例

根据卫星遥感数据的特点,探讨了利用TM数据和SPOT数据对城市绿地景观进行分类的理论和方法,并据此,以上海市为例,把上海市外环线内650km^2范围的绿地景观分为公共绿地、居住区绿地、附属绿地、农林植被和自然植被5大类型,并将每一类型的绿地信息提取出来。     

Remote Sensing Change Detection and Process Analysis of Long-Term Land Use Change and Human Impacts

This study investigates environmental change over a 30-year period and attempts to gain a better understanding of human impacts on an arid environment and their consequences for regional development. Multi-temporal remotely sensed imagery was acquired and integrated to establish the basis for change detection and process analysis. Land cover changes were investigated in two categories, namely categorical change using image classification and quantitative change using a vegetation index. The results show that human-induced land cover changes have been minor in this remote area. However, the pace of growth of human-induced change has been accelerating since the early 1990s. The analysis of the multi-temporal vegetation index also shows no overall trend of rangeland deterioration, although local change of vegetation cover caused by human activities was noticeable. The results suggest that the current trend of rapid growth may not be sustainable and that the implementation of effective counter-measures for environmentally sound development is a rather urgent matter.     

鄱阳湖湿地出露草洲分布特征的遥感研究

利用鄱阳湖区46景不同时相的Landsat MSS/TM/ETM+遥感影像,分别提取鄱阳湖的出露草洲范围,并假定只要一个时期是出露草洲就属于草洲,形成鄱阳湖湿地草洲潜在分布图,并分析鄱阳湖湿地出露草洲的分布特征。研究结果表明：(1)利用出露草洲面积与星子水文站观测水位得到二者的关系,表明出露草洲分布及范围受水位的影响显著,高水位时,大部分草洲被水淹没;低水位时,出露草洲面积大。此外,也受气象因素、草洲植物生长期的水位过程等因素影响;(2)出露草洲面积的季节变化明显：随水位的升高而减少,随水位的下降而增加;在植被生长期的春季和夏季,出露草洲面积逐渐减少,在秋季和冬季,出露草洲面积却逐渐增加;出露草洲面积最大在1月,最小在7月;(3)鄱阳湖潜在草洲的面积达2 441 km2,草洲可能出现的范围占整个鄱阳湖面积的69.5%     

湖南永吉高速公路建设的景观格局影响评价

利用遥感（RS）、全球定位系统（GPS）与地理信息系统技术（GIS）,对湖南省永吉高速公路沿线建设前后的景观进行分类和制图,结合景观结构分析软件Fragstats33和景观生态学方法,从斑块和景观两个层次上研究高速公路建设前后景观格局的变化。结果表明：（1）斑块层次指数中,沿线除公路用地外各景观类型的面积均有所减少,257%的土地转换为公路用地,其中旱地面积减少最多,但是公路建设前后没有改变该区域的优势斑块类型;（2）景观层次指数中,斑块数目和斑块密度的增加与最大斑块指数的减少,都表明景观异质性增加;（3）不同缓冲区分析结果表明：高速公路建设对景观格局的干扰突出表现在距公路较近的500 m缓冲区内。本研究方法在未来路网规划与环境影响评价中具有一定应用前景     

Spatial and temporal variations in NO2 distributions over Beijing,China measured by imaging differential optical absorption spectroscopy

During the CAREBEIJING campaign in 2006, imaging differential optical absorption spectroscopy (I-DOAS) measurements were made from 08:00 to 16:00 on September 9 and 10 over Beijing, China. Detailed images of the near-surface NO₂ differential slant column density (DSCD) distribution over Beijing were obtained. Images with less than a 30-min temporal resolution showed both horizontal and vertical variations in NO₂ distributions. For DSCD to mixing ratio conversion, path length along the lines of I-DOAS lines of sight was estimated using the light-extinction coefficient and Ångstrom exponent data obtained by a transmissometer and a sunphotometer, respectively. Mixing ratios measured by an in-situ NO₂ analyzer were compared with those estimated by the I-DOAS instrument. The obtained temporal and spatial variations in NO₂ distributions measured by I-DOAS for the two days are interpreted with consideration of the locations of the major NO_x sources and local wind conditions. I-DOAS measurements have been applied in this study for estimating NO₂ distribution over an urban area with multiple and distributed emission sources. Results are obtained for estimated temporal and spatial NO₂ distributions over the urban atmosphere; demonstrating the capability of the I-DOAS technique. We discuss in this paper the use of I-DOAS measurements to estimate the NO₂ distribution over an urban area with multiple distributed emission sources.     

Exploring the capacity of radar remote sensing to estimate wetland marshes water storage

This paper focuses on the use of radar remote sensing for water storage estimation in wetland marshes of the Paraná River Delta in Argentina. The approach followed is based on the analysis of a temporal set of ENVISAT ASAR data which includes images acquired under different polarizations and incidence angles as well as different environmental conditions (water level, precipitation, and vegetation condition). Two marsh species, named junco and cortadera, were monitored. This overall data set gave us the possibility of studying and understanding the basic interactions between the radar, the soil under different flood conditions, and the vegetation structure. The comprehension of the observed features was addressed through electromagnetic models developed for these ecosystems. The procedure used in this work to estimate water level within marshes combines a direct electromagnetic model, field work data specifically obtained to feed the model, the actual ASAR measurements and a well known retrieval scheme based on a cost function. Results are validated with water level evaluations at specific points. A map showing an estimation of the water storage capacity and its error in junco and cortadera areas for the date where the investigation was done is also presented.     

Remote sensing and GIS for wetland inventory, mapping and change analysis

A multiple purpose wetland inventory is being developed and promoted through partnerships and specific analyses at different scales in response to past uncertainties and gaps in inventory coverage. A partnership approach is being promoted through the Ramsar Convention on Wetlands to enable a global inventory database to be compiled from individual projects and analyses using remote sensing and GIS. Individual projects that are currently part of this global effort are described. They include an analysis of the Ramsar sites' database to map the distribution of Ramsar sites across global ecoregions and to identify regions and wetland types that are under-represented in the database. Given the extent of wetland degradation globally, largely due to agricultural activities, specific attention is directed towards the usefulness of Earth Observation in providing information that can be used to more effectively manage wetlands. As an example, a further project using satellite data and GIS to quantify the condition of wetlands along the western coastline of Sri Lanka is described and trends in land use due to changes in agriculture, sedimentation and settlement patterns are outlined. At a regional scale, a project to map and assess, using remote sensing, individual wetlands used for agriculture in eight countries in southern Africa is also described. Land cover and the extent of inundation at each site is being determined from a multi-temporal data set of images as a base for further assessment of land use change. Integrated fully within these analyses is the development of local capacity to plan and undertake such analyses and in particular to relate the outcomes to wetland management and to compile data on the distribution, extent and condition of wetlands globally.     

A Calibrated,High‐Resolution GOES Satellite Solar Insolation Product for a Climatology of Florida Evapotranspiration1

Paech, Simon J., John R. Mecikalski, David M. Sumner, Chandra S. Pathak, Quinlong Wu, Shafiqul Islam, and Taiye Sangoyomi, 2009. A Calibrated, High‐Resolution GOES Satellite Solar Insolation Product for a Climatology of Florida Evapotranspiration. Journal of the American Water Resources Association (JAWRA) 45(6):1328‐1342. Abstract: Estimates of incoming solar radiation (insolation) from Geostationary Operational Environmental Satellite observations have been produced for the state of Florida over a 10‐year period (1995‐2004). These insolation estimates were developed into well‐calibrated half‐hourly and daily integrated solar insolation fields over the state at 2 km resolution, in addition to a 2‐week running minimum surface albedo product. Model results of the daily integrated insolation were compared with ground‐based pyranometers, and as a result, the entire dataset was calibrated. This calibration was accomplished through a three‐step process: (1) comparison with ground‐based pyranometer measurements on clear (noncloudy) reference days, (2) correcting for a bias related to cloudiness, and (3) deriving a monthly bias correction factor. Precalibration results indicated good model performance, with a station‐averaged model error of 2.2 MJ m^?2/day (13%). Calibration reduced errors to 1.7 MJ m^?2/day (10%), and also removed temporal‐related, seasonal‐related, and satellite sensor‐related biases. The calibrated insolation dataset will subsequently be used by state of Florida Water Management Districts to produce statewide, 2‐km resolution maps of estimated daily reference and potential evapotranspiration for water management‐related activities.     

基于遥感技术的鄱阳湖-长江水体清浊倒置现象的分析

长期以来,在鄱阳湖和长江的交汇处,江水混浊而湖水清澈,然而,近年来江水清澈而湖水混浊。这种鄱阳湖 长江清浊倒置现象引起了广泛的关注,但鲜有研究人员系统分析这种现象的成因。借助中分辨率成像光谱仪（MODIS）和Landsat影像分析这种清浊倒置现象的起始时间和成因。基于MODIS影像反演的鄱阳湖和长江水体透明度显示在2004年以前鄱阳湖北部的水体透明度明显高于长江,而在2005和2006年长江水体透明度高于鄱阳湖北部,出现清浊倒置现象;同期鄱阳湖北部和长江水体透明度对比分析发现这种水体清浊倒置现象受长江水体透明度增加和鄱阳湖水体透明度下降的双重影响,但鄱阳湖北部水体透明度的变化在其中扮演主要角色;由Landsa影像识别的采（运）砂船数量及其与鄱阳湖北部水体透明度关系的分析表明,自2001年开始的鄱阳湖北部的采砂活动引起此区域水体透明度的显著下降.     

图像挖掘技术在林火影像中的应用

提出了林火遥感图像挖掘的概念,描述了图像挖掘技术在林火遥感图像上的具体应用及实现,针对林火部门每天产生并存储的有价值的林火遥感图像,结合林火上所特有的领域知识,提出了一种通过对林火遥感图像进行图像挖掘,可以将林火遥感图像分成有火或无火两类图像的方法。该方法的实现对帮助林火工作人员及早发现火情,做出火灾预测并采取相应措施具有重大的意义。