湿地生态系统雷达遥感监测研究进展

Progress in Monitoring Wetland Ecosystems by Radar Remote Sensing

湿地是地球上最具生产力和最富生物多样性的生态系统之一。湿地具有很高的资源价值、经济价值、环境效益和多种生态功能。湿地研究己成为当前地理科学、环境科学和生态科学等多学科交汇研究的一个热门领域。目前国内外在对湿地研究过程中，采用遥感技术的关注焦点已逐渐从光学遥感转移到雷达遥感上。采用雷达遥感数据监测湿地的研究，经过了20—30年的研究历程，虽取得了一定的研究成果，但是面对复杂性较为突出的湿地生态系统来说，仍有诸多问题需要深入研究。本文从雷达遥感系统的主要参数波长、极化、入射角，以及湿地雷达遥感监测的主要相关专题时相、环境影响和采用的分析技术方面，回顾了国内外主要地理科学文献上发表的相关研究成果，并总结分析了研究结论和研究发展趋势。

Wetlands is important ecosystems with high productivity and abundant biology diversity. Wetlands have high resource values, economic values, environmental values and a variety of ecological functions. Wetlands research has become a highlighted domain that associates with geography, environment and ecology. The earliest article about wetlands monitoring by radar remote sensing appeared around 1970. Afterwards, many satellites radar sensors were launched, such as SEASAT, ERS, JERS-1, Radarsat, Envisat, ALOS and TerraSAR-X; many space shuttle radar sensors were used, such as SIR-A, SIR-B, SIR-C/X-SAR and SRTM; many airplane sensors were applied, such as AIRSAR, EMISAR and E-SAR. Researchers have published a lot of papers about wetlands and radar data. Monitoring wetlands by radar remote sensing have undergone for 20-30 years and yielded many achievements. But a great number of problems for complicated wetlands still need to be further researched. In this paper, main radar parameters including wave length, polarization, and incident angle were discussed, and involved issues such as temporal and environmental effects and analysis technologies were reviewed. Research conclusions published in geographical literatures and development trends were also analyzed. The latest literature shows that multi-dimension radar dataset has been used for wetlands location determi- nation, area estimation, and environmental condition analysis. Wetlands mapping based on radar data is not limited in research. This trend can speed up the use of radar data, and expand the application diversity. It has been a programmed process for flooding region mapping from radar data. Radar data in environment monitoring have become accepted tools in the studies such as epidemic region mapping, rangeland management and pollution prevention. Radar remote sensing plays an important role in protecting fragile wetlands environment. Under any weath- er conditions, radar system can provide high resolution observation data, so it has become a special earth resource monitoring technology. In addition, radar remote sensing can provide land cover type information and underground physical characteristics that cannot be detected by other spectral bands. With the development of multi-bands, multi-polarization, and multi-angle radar remote sensing system, its information value will be continuously boosted.