Flood and waterlogging monitoring over Huaihe River Basin by AMSR-E data analysis

In this paper, we investigated the potential of Advanced Microwave Scanning Radiometer for Earth Observation System （AMSR-E） for flood monitoring. The proposed approach was based on the polarized ratio index （PRI）, which was computed by using AMSR-E data at 37GHz, vertically and horizontally polarized brightness temperature values and the water surface fraction （WSF） got by using the PRI at 37GHz. Moderate Resolution Imaging Spectroradiometer （MODIS） data were used to validate the WSF values. The analysis of flood and waterlogging using the WSF map on July 6, 2003 indicates that the use of WSF for flood and waterlogging disaster assessment is feasible. Utilizing the correlation of WSF derived from AMSR-E and water area derived from MODIS, the water area of the Huaihe River Basin were computed by only using AMSR-E data in the summer of 2003, which overcame the influence of cloud on water estimation using MODIS data during flood.     

A high precision comprehensive evaluation method for flood disaster loss based on improved genetic programming

Precise comprehensive evaluation of flood disaster loss is significant for the prevention and mitigation of flood disasters. Here, one of the difficulties involved is how to establish a model capable of describing the complex relation between the input and output data of the system of flood disaster loss. Genetic programming （GP） solves problems by using ideas from genetic algorithm and generates computer programs automatically. In this study a new method named the evaluation of the grade of flood disaster loss （EGFD） on the basis of improved genetic programming （IGP） is presented （IGP-EGFD）. The flood disaster area and the direct economic loss are taken as the evaluation indexes of flood disaster loss. Obviously that the larger the evaluation index value, the larger the corresponding value of the grade of flood disaster loss is. Consequently the IGP code is designed to make the value of the grade of flood disaster be an increasing function of the index value. The result of the application of the IGP-EGFD model to Henan Province shows that a good function expression can be obtained within a bigger searched function space; and the model is of high precision and considerable practical significance. Thus, IGP-EGFD can be widely used in automatic modeling and other evaluation systems.     

一种有效的离散数据场等值线生成方法

给出了一种有效的离散数据三角形网格等值线生成算法，首先在Delaunay三角剖分算法中引入了闭合点概念，通过在三角形网格生成过程中动态删除闭合点，减少搜索点集大小，提高了原来三角形剖分算法的速度；其次在三角形网格等值线生成算法中提出了凸边和凸边三角形的概念，通过建立凸边链表和凸边三角形链表，并以凸边进行等值线跟踪，简化了三角形网格等值线搜索算法，提高了等值线生成效率。最后在气象天气图离散站点数据基础上给出了详细测试数据，并给出了天气图等值线绘制效果图。     

EOS/MODIS资料在渭河洪涝动态监测中的应用

通过对MODIS资料中植被、水体、土壤等不同地物的光谱特性进行分析,提出了一种用于洪涝灾害监测的遥感资料处理流程和量化判识指标及淹没面积估算方法.并在2003年渭河流域洪涝灾害的监测中进行了实际应用,效果良好.     

THE SIMULATED STORAGE CAPACITY OF FLOOD AND WATERLOGGING IN THE TYPICAL AGRICULTURAL REGION IN JIANGHAN PLAIN

１ＩＮＴＲＯＤＵＣＴＩＯＮＪｉａｎｇｈａｎＰｌａｉｎｉｓｏｎｅｏｆｔｈｅｉｍｐｏｒｔａｎｔｂａｓｅｓｏｆＣｈｉｎａ′ｓａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｖｉｔｙｌｏｃａｔｅｄｉｎｔｈｅｍｉｄｄｌｅＣｈａｎｇｊｉａｎｇＲｉｖｅｒｖａｌｌｅｙｏｆｃｅｎｔｒａｌＣｈｉｎａ．ＴｈｅＪｉａｎｇｈａｎｐｌａｉｎａｐｐｒｏｘｉｍａｔｅｌｙ６．６×１０４ｋｍ２ｉｎａｒｅａａｎｄｏｖｅｒ３０ｍｉｌｌｉｏｎｉｎｐｏｐｕｌａｔｉｏｎｉｓｔｈｅｒｅｎｏｗｎｅｄ“ｃｏｕｎｔｒｙｏｆｆｉｓｈａｎｄｒｉｃｅ＂ｉｎ…     

一种CINRAD雷达基数据读取丢失的改进方法

多普勒天气雷达是目前世界上最先进的气象雷达,已成为对灾害性天气监测、预警的重要手段之一.雷达基数据的读取是做雷达应用软件的基础,针对目前常规方法对雷达基数据的读取遇到的数据丢失的问题,提出一种改进方法.通过对大量数据的分析和读取,发现新的方法能够有效地提取出丢失数据,并且能够根据丢失数据的重要性对图像进行修正,对小尺度龙卷天气的分析有重要意义.     

Comparative analysis of microwave brightness temperature data in Northeast China using AMSR-E and MWRI products

With such significant advantages as all-day observation, penetrability and all-weather coverage, passive microwave remote sensing technique has been widely applied in the research of global environmental change. As the satellite-based passive microwave remote sensor, the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) loaded on NASA’s (National Aeronautics and Space Administration of USA) Aqua satellite has been popularly used in the field of microwave observation. The Microwave Radiation Imager (MWRI) loaded on the Chinese FengYun-3A (FY-3A) satellite is an AMSR-E-like conical scanning microwave sensor, but there are few reports about MWRI data. This paper firstly proposed an optimal spatial position matching algorithm from rough to exact for the position matching between AMSR-E and MWRI data, then taking Northeast China as an example, comparatively analyzed the microwave brightness temperature data derived from AMSR-E and MWRI. The results show that when the antenna footprints of the two sensors are filled with either full water, or full land, or mixed land and water with approximate proportion, the errors of brightness temperature between AMSR-E and MWRI are usually in the range from −10 K to +10 K. In general, the residual values of brightness temperature between the two microwave sensors with the same spatial resolution are in the range of ±3 K. Because the spatial resolution of AMSR-E is three times as high as that of MWRI, the results indicate that the quality of MWRI data is better. The research can provide useful information for the MWRI data application and microwave unmixing method in the future.     

RESEARCH ON SYSTEM OF FLOOD DISASTER CONTROL AND REDUCTION SUPPORTED BY GIS IN MEDIUM AND SMALL BASINS

Southeast China coastal areas belong to subtropical monsoon climatic zone,thus easily affected by floods resulted from typhoons and rainstorm.Since the areas of river basins are small,rivers flood regulation capacities are low,and therefore flood hazard is grave.In the paper,taking the Yongjiang basin in southeast China as an example,the approaches and methods of geographic information system(GIS) applied to flood disaster control and reduction research on small basin are explred.On GIS help the rainfall-runoff calculation model and the river dchannel flood routing model are developed.And the evaluating flood submerged are and the damage assessment models are built supported by digit elevation models.Lastly the decision support system on GIS supported for flood control in research basin has been set up.This greatly improves flood-proofing decision-making capacities in river basin,and provides valuable information and a mode for flood prevention and reduction in the medium and small basin .Meanwhile,the research indicates that technologies of GIS provide a powerful tool for flood disaster control.     

A comparison of Argo nominal surface and near-surface temperature for validation of AMSR-E SST

Satellite SST(sea surface temperature) from the Advanced Microwave Scanning Radiometer for the Earth Observing System(AMSR-E) is compared with in situ temperature observations from Argo profiling floats over the global oceans to evaluate the advantages of Argo NST(near-surface temperature: water temperature less than 1 m from the surface). By comparing Argo nominal surface temperature(~5 m) with its NST, a diurnal cycle caused by daytime warming and nighttime cooling was found, along with a maximum warming of 0.08±0.36°C during 14:00–15:00 local time. Further comparisons between Argo 5-m temperature/Argo NST and AMSR-E SST retrievals related to wind speed, columnar water vapor, and columnar cloud water indicate warming biases at low wind speed(5 m/s) and columnar water vapor 28 mm during daytime. The warming tendency is more remarkable for AMSR-E SST/Argo 5-m temperature compared with AMSR-E SST/Argo NST, owing to the effect of diurnal warming. This effect of diurnal warming events should be excluded before validation for microwave SST retrievals. Both AMSR-E nighttime SST/Argo 5-m temperature and nighttime SST/Argo NST show generally good agreement, independent of wind speed and columnar water vapor. From our analysis, Argo NST data demonstrated their advantages for validation of satellite-retrieved SST.     

一种改进的Apriori挖掘算法

针对制约Apriori算法效率的瓶颈问题,提出了一种基于Apriori的改进算法,算法只需要遍历一次事务数据库,避免了Aprori算法多次扫描事务数据库和产生大量的候选项集,同时利用项集的有序性改进了判断连接的方式,优化了连接步骤,减少了判断时间.实验结果表明,改进的Apriori算法在运行效率上有一定的提高.     

Effects of surface waves and ship heave-and-roll on CTD data and processing method for CTD data

The effects of surface waves and ship heave-and-roll on CTD data are discussed. The heave-and-roll produces spurious step-like structures in the CTD data. Derivation of a formula for calculating the probe's fall speed is discussed. Several current techniques for CTD sensor lag correction are analyzed and compared. It is shown the lag correction procedure presented here, which is based on the Giles-McDougall technique, can be employed to treat CTD data from regions with slow or fast T-S variations, for instance, in strong seasonal thermocline. False salinity spikes or humps in data corrected with this procedure are significantly reduced. The project is supported by the Natural Science Foundation of China and Chinese Education Committee     

Geometrical feature analysis and disaster assessment of the Xinmo landslide based on remote sensing data

At 5:39 am on June 24, 2017, a landslide occurred in the village of Xinmo in Maoxian County, Aba Tibet and Qiang Autonomous Prefecture(Sichuan Province, Southwest China). On June 25, aerial images were acquired from an unmanned aerial vehicle(UAV), and a digital elevation model(DEM) was processed. Landslide geometrical features were then analyzed. These are the front and rear edge elevation, accumulation area and horizontal sliding distance. Then, the volume and the spatial distribution of the thickness of the deposit were calculated from the difference between the DEM available before the landslide, and the UAV-derived DEM collected after the landslide. Also, the disaster was assessed using high-resolution satellite images acquired before the landslide. These include Quick Bird, Pleiades-1 and GF-2 images with spatial resolutions of 0.65 m, 0.70 m, and 0.80 m, respectively, and the aerial images acquired from the UAV after the landslide with a spatial resolution of 0.1 m. According to the analysis, the area of the landslide was 1.62 km2, and the volume of the landslide was 7.70 ± 1.46 million m3. The average thickness of the landslide accumulation was approximately 8 m. The landslide destroyed a total of 103 buildings. The area of destroyed farmlands was 2.53 ha, and the orchard area was reduced by 28.67 ha. A 2-km section of Songpinggou River was blocked and a 2.1-km section of township road No. 104 was buried. Constrained by the terrain conditions, densely populated and more economically developed areas in the upper reaches of the Minjiang River basin are mainly located in the bottom of the valleys. This is a dangerous area regarding landslide, debris flow and flash flood events Therefore, in mountainous, high-risk disaster areas, it is important to carefully select residential sites to avoid a large number of casualties.     

一种面向现代GPU的大规模地形渲染技术

将地形数据均匀地划分为分页,通过基于视点的预加载方法和分页缓冲池管理技术实现海量地形数据的实时调度.沿用LOD算法基本思想,将已加载的分页再划分为若干个分块,以分块为单位进行批量渲染,并把不同细节等级分块之间的裂缝处理提前至预处理阶段进行,减少CPU的实时运算量.实验表明,该算法能使CPU与GPU之间更协调的工作,实现了大规模三维地形的高效渲染.     

一种自适应阈值选择方法

提出了一种新的自适应阈值选择方法。该方法基于图像的灰度级特征，以前景和背景最大程度地分开为判据，定义了新的阚值识别函数来选择最佳的阈值，对图像进行分割。同时，还给出了该方法的应用实例和分割结果的比较与分析。结果表明该方法不仅对灰度级谷地明显的图像适用，而且对灰度级谷底不太明显的图像，也能达到比较满意的分割效果。     

Study of denoising method for nonhyperbolic prestack seismic reflection data

Removing random noise in seismic data is a key step in seismic data processing. A failed denoising may introduce many artifacts, and lead to the failure of final processing results. Seislet transform is a wavelet-like transform that analyzes seismic data following variable slopes of seismic events. The local slope is the key of seismic data. An earlier work used traditional normal moveout(NMO) equation to construct velocity-dependent(VD) seislet transform, which only adapt to hyperbolic condition. In this work, we use shifted hyperbola NMO equation to obtain more accurate slopes in nonhyperbolic situation. Self-adaptive threshold method was used to remove random noise while preserving useful signal. The synthetic and field data tests demonstrate that this method is more suitable for noise attenuation.     

The use of UAVs for landslide disaster risk research and disaster risk management: a literature review

On a global scale,from 2005 to 2019,there were 275 high-magnitude,low-frequency disasters that involved 14,172 fatalities and four million affected people.Similar patterns have taken place during longer periods of time in recent decades.This paper aims to analyse the contribution of the international landslide research community to disaster risk reduction and disaster risk management in reference to the use of Unmanned Aerial Vehicles(UAVs)in a literature review.The first section notes the relevance of disaster risk research contributions for the implementation of initiatives and strategies concerning disaster risk management.The second section highlights background information and current applications of drones in the field of hazards and risk.The methodology,which included a systematic peer review of journals in the ISI Web of Science and SCOPUS,was presented in the third section,where the results include analyses of the considered data.This study concludes that most current scholarly efforts remain rooted in hazards and post-disaster evaluation and response.Future landslide disaster risk research should be transdisciplinary in order to strengthen participation of the various relevant stakeholders in contributing to integrated disaster risk management at local,subnational,national,regional and global levels.     

An improved siphon drainage method for slope stabilization

The siphon drainage is an effective measure for the slope groundwater control. However,for the traditional siphon drainage, limitations such as siphon lift restriction and poor reliability in longterm service prevent it from being widely used. In this study, an improved siphon drainage method with inclined borehole penetrating the deep part of the slope is proposed to overcome the limitations suffered by the traditional method. Through experimental research, theoretical analysis and engineering practice,the reliability and capability of the proposed method are investigated. The results demonstrate that with the inclined pipe the height difference between the control point of the groundwater level and the orifice can be controlled to be less than the height of the water column corresponding to the local atmospheric pressure. As a result, deep drainage can be achieved.In addition, by controlling the diameter of siphon drainage pipe not larger than 4 mm, a plug flow can be formed in the siphon pipe, which can prevent air accumulation in the siphon process and a continuous and effective siphon drainage is achieved. Through a practical project running smoothly since September 2013, it is found that the proposed method can effectively drain the groundwater deep in the slope and the maximum drawdown of groundwater level in boreholes can reach 8.5 m with an average drainage flow of 5.5 m3/d. The practical results also illustrate that 4 mm siphon pipe can be used to realize deep slope drainage and restart siphon automatically.     

Disaster reduction stick equipment: A method for monitoring and early warning of pipeline-landslide hazards

Oil and gas pipelines are of great importance in China, and pipeline security problems pose a serious threat to society and the environment.Pipeline safety has therefore become an integral part of the entire national economy. Landslides are the most harmful type of pipeline accident, and have directed increasing public attention to safety issues.Although some useful results have been obtained in the investigation and prevention of pipeline-landslide hazards, there remains a need for effective monitoring and early warning methods, especially when the complexity of pipeline-landslides is considered.Because oil and gas pipeline-landslides typically occur in the superficial soil layers, monitoring instruments must be easy to install and must cause minimal disturbance to the surrounding soil and pipeline. To address the particular characteristics of pipelinelandslides, we developed a multi-parameter integrated monitoring system called disaster reduction stick equipment. In this paper, we detail this monitoring and early warning system for pipeline-landslide hazards based on an on-site monitoring network and early warning algorithms.The functionality of our system was verified by its successful application to the Chongqing Loujiazhuang pipeline-landslide in China. The results presented here provide guidelines for the monitoring, early warning, and prevention of pipeline geological hazards.