长江三角洲主要水体水质污染的遥感研究

用遥感技术来进行水环境监测是近年来常用的手段之一。由于不同污染水体的绿度、温度和透明度差异反映了物理场的不同，因此，在遥感技术中用NOAA／AVHR气象卫星测定绿度、温度和透明度三类数据可完整地识别不同水体的水质变化。采用气象卫星的复合比值合成图像和色调-饱和度-明度变换技术，有效地反映长江三角洲主要水体的水质污染情况，并且可同上海市航空遥感综合调查与研究资料和太湖的水质研究资料互相印证，其水质类型可以用数据予以确定和解释。本研究反映了长江三角洲全区主要水体水质的宏观分布，为水质污染的宏观监测提供了依据，表明气象卫星在以水质研究为主的环境遥感中的优越性。它具有覆盖面广、时相连续、费用低廉的优势，宜于对大区域内具一定面积的水体作连续性的宏观监控观察，这是单一的航空红外或彩红外遥感技术无法相比的。但是，它存在着分辨率低的缺点，必须指出，在处理过程中在上海市、苏锡常、苏北的南通、泰州、东台等河流纵横的地区，显示了众多与苏州河、蕴藻浜相同的6级水异常点区，反映这些地区存在着广泛分布的水污染问题，它们将影响这些地区的可持续性发展。由于受NOAA气象卫星分辨率低的限制，无法精确标出它们的确切位置。因此，在应用中对污染剧化应予重点监控的部位可以按照需要开展适量的彩红外航空遥感、航天小卫星或资源卫星遥感，互相结合补充予以解决。

Remote sensing study of main waterbody pollution in Changjiang delta region

With the rapid development of our economy, water pollution is becoming more and more of public concern. Remote sensing technology has proved to be a fast and economical method in monitoring the water environment. In general aero infrared photos or Landsat images or hyperspectral remote sensing or space micro-satellite data are used in monitoring urban and the suburbs environment, but these data are costly and hard to be found. To normal water, NOAA/AVHRR ch2 - chl < 0; but in eutrophication water ch2 - ch1 > 0. This band combination can be a discerning signal of normal water and abnormal water. Since different polluted water bodies show different hues, temperatures, and transparency, the three are indicators of water physical status and are integrated into one indivisible part. So the NOAA/AVHRR images are used to measure hue, temperature, and transparency, in order to discern the different pollution level of water bodies in the Changjiang delta region by remote sensing. Based on ratio composed images of NOAA/AVHRR and HLS transformed images, the Changjiang delta region main water body quality is studied in this paper. The result is verified by Taihu Lake water survey data and Shanghai aero-remote sensing investigation data, and the water quality types can be identified by digital values. Our research shows that the NOAA/AVHRR based method has the advantages of continuous monitoring and researching on large-scale water body pollution. This research also makes clear the large scale distribution of the Changjiang delta region main water body quality and provides evidence for macroscopically monitoring of water quality. The NOAA/AVHRR method has the merits of large scale, being continuous, and cheap in cost, it is suitable for use in regional monitoring of water quality continuously. This merit can not be replaced by the aero infrared photos, Landsat images, or hyperspectral remote sensing. But on the other hand, we must point out that it also has the disadvantage of low resolution. In this study, due to the low resolution, a lot of abnormity of data occurred in Shanghai, Suzhou, Wuxi, and Changzhou, but their precise locations are hard to be made out. In real environment monitoring application, the aero infrared photos, Landsat images, hyperspectral remote sensing, and low resolution images should be used together to obtain their best results.