基于TRMM降尺度和MODIS数据的综合干旱监测模型构建

京津冀地区是我国优质冬小麦的主产区之一,但在全球气候变暖影响下,该地区干旱灾害频发,因此准确监测京津冀地区旱情既能为区域农业生产提供科学指导,又起到保障国家粮食安全等重大战略作用。综合考虑干旱发生过程中大气降水—植被生长—土壤水分盈亏等致旱因子,首先利用GWR（Geographically Weighted Regression）模型对TRMM（Tropical Rainfall Measuring Mission）3B43数据进行降尺度处理,得到1 km分辨率的降水状态参数（Precipitation Condition Index,PCI）;再结合MODIS（Moderate-Resolution Imaging Spectroradiometer）数据,得到植被状态指数（Vegetation Condition Index,VCI）、温度状态指数（Temperature Condition Index,TCI）,最后基于多元回归模型构建综合干旱指数（Comprehensive Drought Index,CDI）,以实现对京津冀地区干旱时空监测评价。结果表明：（1）基于GWR模型与占比系数法得到的1 km空间分辨率TRMM年数据、月尺度数据,不仅在空间分辨率上相比原始TRMM数据得到很大的提升,并且数据精度也通过了检验,表明降尺度分析提高了TRMM数据对研究区降水时空特征的描述能力;（2）监测模型结果与京津冀地区所经历的干旱历程等实际旱情基本一致,并且CDI指数与标准化降水指数（Standardized Precipitation Index,SPI）做相关分析,其相关系数R在0.45~0.85之间,与作物受旱面积做相关分析,相关系数R介于在-0.81~-0.86之间,与作物标准化单产进行相关分析,其相关系数R均大于0.6,并且均通过P<0.05的显著性检验,表明本文所构建的综合干旱监测模型在京津冀地区是适用的。     

Satellite-based indices in the analysis of land cover for municipalities in the province of Siena, Italy

Territorial indicators based on the satellite measured reflected or emitted energy can provide valuable information on the spatial evolution of a territory. Information regarding land use, biomass coverage and radiant temperature were obtained from remotely obtained measurements for each municipality in the Province of Siena. Remotely sensed data were combined into different indices to compare characteristics of land cover between territories and create an information base for continued study. A classification was performed on a municipal level and land use classes were grouped together and a general index of use pressure was created. A vegetation index was used to compare biomass densities. A radiant temperature index was calculated using measure thermal infrared emissions. The results of these analyses allowed researchers to examine the intra and inter-municipal spatial heterogeneity within the Province. A comparison between the results of each index was made and the problems related to the use of such indices were examined.     

Riparian vegetation dynamics and evapotranspiration in the riparian corridor in the delta of the Colorado River, Mexico

Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow of the Lower Colorado River has entered the riparian corridor below the last diversion point for water in Mexico. These flows include flood releases from US dams and much smaller administrative spills released back to the river from irrigators in the US and Mexico. These flows have germinated new cohorts of native cottonwood and willow trees and have established an active aquatic ecosystem in the riparian corridor in Mexico. We used ground and remote-sensing methods to determine the composition and fractional cover of the vegetation in the riparian corridor, its annual water consumption, and the sources of water that support the ecosystem. The study covered the period 2000-2004, a flood year followed by 4 dry years. The riparian corridor occupies 30,000ha between flood control levees in Mexico. Annual evapotranspiration (ET), estimated by Moderate Resolution Imaging Spectrometer (MODIS) satellite imagery calibrated against moisture flux tower data, was about 1.1myr(-1) and was fairly constant throughout the study period despite a paucity of surface flows 2001-2004. Total ET averaged 3.4x10(8)m(3)yr(-1), about 15% of Colorado River water entering Mexico from the US Surface flows could have played only a small part in supporting these high ET losses. We conclude that the riparian ET is supported mainly by the shallow regional aquifer, derived from agricultural return flows, that approaches the surface in the riparian zone. Nevertheless, surface flows are important in germinating cohorts of native trees, in washing salts from the soil and aquifer, and in providing aquatic habitat, thereby enriching the habitat value of the riparian corridor for birds and other wildlife. Conservation and water management strategies to enhance the delta habitats are discussed in light of the findings.     

卫星遥感在大雾生消动态监测中的应用

利用ＧＭＳ－５静止气象卫星资料，研究大雾生消动态遥感监测方法，并用此方法对沪宁高速公路大雾进行实时监测，取得了较好的效果。     

大气气溶胶地基光学遥感物联网系统研究

研究了大气气溶胶地基光学遥感物联网系统的设计问题.根据其应用特点从传感层、传输层、数据层、应用层这几个组成部分对系统进行了设计,并初步实现.测试表明:设计的大气气溶胶地基光学遥感物联网系统具有支持数据实时共享、无人值守运行、快速数据融合、环境参数在线显示、历史数据快速查询和分析、仪器远程管理维护等优点,可实现大气气溶胶特性的网络化和自动化观测,对研究气溶胶对环境和气候的影响具有重要应用价值.     

基于RS与GIS的规划用地生态适宜性评价

利用遥感影像获取研究区土地利用类型,并运用GIS空间分析功能,分析了影响开发区规划用地生态适宜性的7个因子,并以此对生态适宜性进行综合评价,得到了定量化的评价结果,为区域规划奠定了基础。     

集成遥感和GIS的元胞自动机城市生长模拟

元胞自动机（Cellular Automata, CA）因其“自下而上”的自组织性能够呈现复杂的全局结构，越来越多地应用于城市生长和演化模拟。从历史遥感影像中提取了对城市生长影响较大的空间距离变量，结合实测数据和规划数据，挖掘基于Logistic回归的地理CA转换规则，建立了Logistic CA模型。在自主开发的基于GIS的地理模拟框架下，以中小尺度城市上海市嘉定区为例，利用该Logistic CA模型模拟和重建了该区1989~2006年城市生长过程。将模拟结果与遥感影像分类的结果进行逐象元比较，获取混淆矩阵和Kappa系数，从而对模型模拟结果进行评价。研究表明:Logistic CA模型适合于中小尺度城市生长模拟，模拟结果与城市实际形态相符，精度较好。最后，基于嘉定区城市发展态势不变的假设，预测了其2010年城市生长的可能情景。     

三峡水库156米蓄水位消落区植被恢复遥感动态监测研究

基于2007～2009年的Landsat5 TM、HJ 1A/1B CCD遥感数据，利用像元二分法对三峡水库156 m蓄水位消落区的植被覆盖度进行了计算，分析了消落区植被恢复的时空变化特征，探讨了植被恢复时空变化的影响因子。2007、2008、2009年3 a 156 m蓄水位消落区植被覆盖度分别为512%、515%、492%，其中支流消落区的植被覆盖度高于干流，这与地形条件有关，坡度的大小决定了消落区植被覆盖的空间差异。2008年与2007年消落区植被覆盖状况基本一致，而2009年的植被覆盖度低于之前两年，这与三峡大坝水位调度方案不同有关，退水较晚时，植被生长时间较短，其植被覆盖度较低。研究结果表明，在正常的调度、一定的地形条件下，淹没数月的消落区植被具有一定的自然萌生能力。     

基于时空数据融合的江汉平原水稻种植信息提取

及时、准确监测水稻种植面积,对区域粮食政策制定、粮食安全以及农业发展具有重要意义。然而我国南方地区水稻生长期内降水充沛的气候特点使得遥感影像"云污染"现象严重,为解决水稻种植信息遥感提取存在可用数据不足的问题,以江汉平原为例,利用时空数据融合模型(Spatial and Temporal Data Fusion Approach,STDFA)将Landsat 8 OLI与时序MODIS数据融合,重构出具有高时-空分辨率特征数据,然后采用面向对象的SVM分类方法对研究区内水稻种植信息进行提取,结果如下:融合后的红与近红外波段反射率与真实反射率的相关系数分别为0.84和0.81,研究区水稻提取精度为94.46%,Kappa系数为0.91。说明时空融合模型能够较好地重构出高时空分辨率数据,从而实现多云雨地区农作物种植信息遥感提取。     

Landsat5 TM遥感影像上太湖蓝藻水华反射光谱特征研究

利用ENVI遥感软件的FLAASH工具对2005年10月17日大规模蓝藻水华暴发的太湖Landsat5 TM影像进行大气校正处理,反演获得蓝藻水华和其他地物类型的遥感反射率图像,提取了不同集聚程度蓝藻水华的可见波段至近红外波段反射率数据,并与陆生植被、无蓝藻水面等地物的光谱反射率进行了比较。研究表明,与陆生植被、无蓝藻水面相比,蓝藻水华在TM2波段和TM4波段具有更高的反射率,在可见光波段整体反射率略高于陆生植被,在TM5、TM7波段则受水的影响反射率很低。从蓝藻水华、陆生植被的细胞生理结构、生长环境、复杂的遥感反射、散射及透射模型方面初步讨论了光谱差异的原因。