Flood management consists many aspects such as hazard assessment, vulnerability assessment, exposure assessment, risk assessment, early warning system, damage assessment as well as risk mitigation planning. Conventional flood management are depending on the ground based monitoring of rainfall and river discharge. Many parts of the world are not covered by these sensor networks in one hand and these ground based systems are costly. Most of the tropical countries have high flood risk and low financial and institutional capacity to afford ground based system. While conventional flood management is time and cost intensive, spaceborne remote sensing provides timely and low-cost data in comparison to field observation, and is the obvious choice for most developing countries affected by flooding. Many aspects of flood management are being aided with the advancement of remote sensing technology. More precise and near real time flood detection, lead time in flood early warning system, accurate and advance inputs of hydrological models are now blessed by space technology. Many methods and approaches have been developed to overcome the constrains in the application of spaceborne remote sensing in flood management. Application of satellite remote sensing in flood hazard assessment is well documented, however, the application of space technology in other aspects of the flood management is also promising. Therefore, this review paper focuses on the applicability of spaceborne remote sensing and in most of the aspects in flood management.
Natural Hazards - Inner Mongolia, located in the northern China, is a natural disaster-prone region. This study is dedicated to making a comprehensive and quantitative analysis of the... 相似文献
The fundamental researches about thermal physical properties of rocks have much concern in oil and gas field. They go through four stages and are applied in thermal structure of lithosphere, thermal evolution of sedimentary basins, geotechnical engineering and geothermal area. This article summarized the current research progress on the basis of thermal physical properties of rocks and proposed the development of tendency for the future. Moreover, some cylindrical heat pipe, disc heat pipe, spherical heat pipe based on in-situ measurement method and prediction model based on mathematical statistics have been developed. The scholars discuss the internal relation between thermal conductivity parameter of rocks and other physical properties by a large number of experiments. The researches show that the thermal conductivity of rocks is affected by many factors, and the petrologic characteristic is the most important factor. The porosity of rocks, filled fluid properties, acoustic characteristics are also related to thermal conductivity, which is affected by temperature, pressure and anisotropy. In consideration of the study of thermal physical properties of rocks, we proposed the following tendency for the future. First of all, shale gas is regarded as a hot spot in oil-gas exploration and the formation mechanism and the formation of shale gas reservoir are under the control of thermal physical properties of shale gas, but the relationship among thermal conductivity and organic porous, organic carbon content, gas content, fractured characteristics remains unknown. Therefore, exploring the thermal physical properties of gas-bearing shale is an important research direction in oil and gas field. Secondly, the study of big data represents the general trend. Though the database of rocks thermal parameter is continually expanding, measuring in-situ thermal conductivity continuously in well is the best method to get the accurate in-situ thermal conductivity of rocks. Hence, the development of logging method principle and logging instruments based on thermal physical properties of rocks is a necessary trend for the future. 相似文献
Wetland plant communities in the plateau lakes of Yunnan Province, China, have decreased significantly over the past decades. To better understand this degradation, we analyzed the processes and characteristics of changes in wetland plant communities in two of the largest lakes in Yunnan Province, Dianchi and Erhai lakes. We collected records of native and alien plant communities in the two lakes from literature published from the 1950s to current period. We calculated plant community types and their area in some historical periods when related data were reported, and analyzed the relationship between changes in plant communities and water pollution. In Dianchi Lake, 12 community types of native plant communities, covering over 80% of the surface in the 1950s and 1960s, were reduced to four types covering 2.4% by the late 2000s. Alien plant communities started to appear in the lake in the late 1970s, and have since come to cover 4.9% of the lake surface, thereby becoming dominant. In Erhai Lake, 16 community types of native plant communities, covering 47.1% of the lake surface in the late 1970s, declined to 10 community types, covering 9.3% of the surface, by the late 2000s. Alien plant communities appeared in the middle 1980s, and at present cover 0.7% of the surface area. It was indicated that changes in plant communities were significant related to water eutrophication. The area occupied by native and alien plant communities was, respectively, negatively and positively related to the content of nutrients in water. This showed lacustrine pollution played an important role in native plant loss and alien plant invasion in the two plateau lakes. 相似文献
Land cover classification (LCC) in arid regions is of great significance to the assessment, prediction, and management of land desertification. Some studies have shown that the red-edge band of RapidEye images was effective for vegetation identification and could improve LCC accuracy. However, there has been no investigation of the effects of RapidEye images’ red-edge band and vegetation indices on LCC in arid regions where there are spectrally similar land covers mixed with very high or low vegetation coverage information and bare land. This study focused on a typical inland arid desert region located in Dunhuang Basin of northwestern China. First, five feature sets including or excluding the red-edge band and vegetation indices were constructed. Then, a land cover classification system involving plant communities was developed. Finally, random forest algorithm-based models with different feature sets were utilized for LCC. The conclusions drawn were as follows: 1) the red-edge band showed slight contribution to LCC accuracy; 2) vegetation indices had a significant positive effect on LCC; 3) simultaneous addition of the red-edge band and vegetation indices achieved a significant overall accuracy improvement (3.46% from 86.67%). In general, vegetation indices had larger effect than the red-edge band, and simultaneous addition of them significantly increased the accuracy of LCC in arid regions. 相似文献