Research And Implementation Of River Runoff Monitoring System Based On Multi-source Radar Remote Sensing Technology

Rivers are an important source of water for human beings.They are closely related to human life and production.They are also an important part of the Earth's water cycle and play a vital role in regional economic development and climate change.River runoff is one of the most important hydrological elements on land and an essential element of water balance.In recent years,with the advancement of science and technology and the development of human society,people have paid more and more attention to the monitoring of river runoff.However,due to the impact of rising global temperatures,extreme hydrological phenomena such as floods and droughts and the possibility of severe weather such as thunderstorms and heavy rains increase,and river runoff monitoring tasks will directly affect the safety of people in the surrounding areas.Therefore,the use of remote sensing technology to monitor river runoff has become an important research topic.Radar remote sensing has the ability to observe all-time and all-weather,and has the ability to penetrate clouds,rain and fog,and is not susceptible to weather.Therefore,the use of radar altimetry measuring height technology and Synthetic Aperture Radar(SAR)information extraction technology for river remote sensing monitoring research has very important practical significance.This paper takes China's second longest river,the Yellow River,as the research area,based on radar altimetry measuring height technology and SAR image information extraction technology,and carries out remote sensing monitoring research on river width,water level and runoff.River runoff refers to the amount of water passing through a certain cross section of a river in a certain period of time,which can be calculated from hydrological parameters such as river width,water level and flow velocity.Based on multi-source radar remote sensing technology,this paper uses radar altimetry data to extract river water level,and uses SAR image processing to obtain river area information,and calculates river width.Then based on the Manning formula,the relationship between river width,water level and other measured runoff data is processed by the relationship fitting method to construct the river runoff calculation model.It is verified by experiments that the radar altimetry measuring height technology and SAR image information extraction technology can be effectively used in the monitoring of river-related parameters,and it has the potential to improve the monitoring accuracy based on the research.The main work and innovations of this paper can be summarized as the following three aspects:(1)Obtaining river parameters based on multi-source radar remote sensing technologyThis paper proposes a processing method based on multi-source radar remote sensing technology to extract river parameters.Considering the wide river basin and complex geographical environment,it is necessary to consider the effects of nighttime,weather and environment when monitoring rivers by remote sensing technology.According to the above requirements,this paper acquires river water level and river width data based on radar altimetry measuring height technology and SAR image information extraction technology.This method has the characteristics of all weather and weather-free,and can not only complete river runoff under extreme conditions,and obtain river width and water level data more accurately.(2)Constructing multi-source radar remote sensing runoff calculation modelThis paper proposes a multi-source Radar Remote Sensing-Runoff Calculation Model(MRRS-RCM).When calculating river runoff,parameters such as river width,water depth and flow velocity are usually required.However,it is difficult to obtain river flow velocity by current SAR remote sensing technology,and some parameters such as river bottom elevation and river bottom width are difficult to obtain.Based on the Manning formula,this paper converts the flow velocity into the numerical relationship between river width and water depth.The lowest measured water level in recent years is used as the relative river bottom elevation,and the measured runoff is used as the reference runoff,and the water level result extracted by radar remote sensing is converted into Relative to the water depth.Using the relationship fitting method to fit the relative water depth,river width extraction results and measured runoff data,the river empirical parameter rep(used It expresses the unknown water surface slope ‘S' and Manning's roughness coefficient ‘n')was obtained to construct the MRRS-RCM model.(3)Design and implement a river runoff monitoring systemBased on the MRRS-RCM model,this paper designs and implements a river runoff monitoring system.The system mainly realizes the river width calculation function,the river water level calculation function,the river runoff calculation function and the runoff process line drawing function.Among them,the river width calculation function is based on the system extracting the river surface in the SAR image data,calculating the water surface area according to the latitude and longitude information,and dividing by the length of the river section to realize the river width calculation.The river water level calculation function selects the radar altimetry data at the research site by the system,extracts the elevation information of the water surface position,and realizes the water level calculation.The river runoff calculation function is to calculate the river width and river water level calculated above into the river runoff calculation model and calculate the river runoff.The runoff process line drawing function is realized by the system searching the runoff data of the user selection time and the research station,and drawing the runoff process line.