On subtropical remote sensing in China：Research status，key tasks and innovative development approaches

Abstract

The subtropical region of China covers a vast area with special and unique geographical characteristics. Typical geographical characteristics include complex natural landscape with a mass of mountains and forests, cloudy and rainy climate, and rich biodiversity. And the subtropical region is the major producing areas of rice in China. Moreover, the subtropical region has abundant rivers, lakes, and mineral resources, which induce the sewage from the mining area spread widely along the river basins. All these geographical characteristics lead to high ecological environment sensitivity and frequent natural disasters of subtropical region in China. The characteristics of remote sensing for large range of rapid observation make it essential for precise monitoring of natural resources and environmental disasters in the wide subtropical region. Furthermore, it is urgent to develop special remote sensing theory and technology for subtropical region in China, so as to support the sustainable development and ecological civilization construction. In recent years, many researchers have gradually paid their attention to the subtropical satellite remote sensing. Internationally, the research topics mainly include land use cover change, urban environmental monitoring, wetland mapping, earthquake damage and its secondary disaster monitoring, water quality monitoring, vegetation biomass inversion, and aerosol parameter inversion and so on. In China, scholars mainly focus on some specific applications, such as flood disaster monitoring, mangrove monitoring, and forest degradation etc. These works provide abundant cases and raw materials for the formation and development of the theoretical system of subtropical remote sensing. However, most of the current studies just concentrated on some particular objects, local areas, or specific problems. So far, the theory and technology system of subtropical remote sensing is still in its infancy, and lacks in systematic analysis on characteristics of research status, fundamental problems and future development. In this paper, we first described the basic characteristics of subtropical region of China and the related practice researches in remote sensing. In this part, we analyzed the practice of remote sensing in subtropical region from the perspective of remote sensing data sources, including optical, hyperspectral, microwave, and multi-source data. Furthermore, we discussed the common problems of the practical researches in subtropical remote sensing. In this part, we analyzed and pointed out the two fundamental problems of subtropical remote sensing, i.e. the problems of geographical objects and remote sensing information. Accordingly, we elucidated the key tasks and scientific problems derived from the two fundamental problems. Then, we analyzed the historical opportunity of subtropical remote sensing development, and put forward the core scientific problems and development approaches of subtropical remote sensing that should be focused on in the future. In conclusion, there are some basic features and common problems in subtropical remote sensing. The innovation and development of subtropical remote sensing, including the collaborative observations of multiple sensors and various platforms, are inevitable trend. This paper aims to explore the development ideas for theories and methods of subtropical remote sensing. Meanwhile, we commit to clarify the innovation direction of subtropical remote sensing technology and application. Most important of all, we hope to promote the application of remote sensing in resource and environment monitoring, disaster prevention and reduction, and ecological civilization construction in the subtropical region of China.