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This paper describes a geographic information system(GIS)-based method for observing changes in topography caused by the initiation, transport, and deposition of debris flows using highresolution light detection and ranging(LiDAR) digital elevation models(DEMs) obtained before and after the debris flow events. The paper also describes a method for estimating the volume of debris flows using the differences between the LiDAR DEMs. The relative and absolute positioning accuracies of the LiDAR DEMs were evaluated using a real-time precise global navigation satellite system(GNSS) positioning method. In addition, longitudinal and cross-sectional profiles of the study area were constructed to determine the topographic changes caused by the debris flows. The volume of the debris flows was estimated based on the difference between the LiDAR DEMs. The accuracies of the relative and absolute positioning of the two LiDAR DEMs were determined to be ±10 cm and ±11 cm RMSE, respectively, which demonstrates the efficiency of the method for determining topographic changes at an scale equivalent to that of field investigations. Based on the topographic changes, the volume of the debris flows in the study area was estimated to be 3747 m3, which is comparable with the volume estimated based on the data from field investigations. 相似文献
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Debris flow in metropolitan area — 2011 Seoul debris flow 总被引：4，自引：2，他引：2
Chan-Young Yune Yun-Ki Chae Joongcheol Paik Gihong Kim Seung-Woo Lee Heung-Seok Seo 《山地科学学报》2013,10(2):199-206
A large number of debris flows occurred simultaneously at around 8:30 to 8:50 a.m. on July 27, 2011, at the center of Seoul, Korea. This area is located in the southern part of Seoul and is a densely populated district. As a result of the debris flow event, 16 people were killed, 30 houses were buried, and 116 houses were damaged around Umyeon Mountain, a relatively small mountain with a height of 312.6 m. Since the debris flow event, field investigations on the initiation and transportation zones of debris flows have been carried out. Rainfall data were collected from the automatic weather stations (AWSs) which are operated by the Korea Meteorological Administration (KMA). Video files recorded by residents were also acquired and used to analyze the flow characteristics of the debris flow. Field investigation shows that about 40 debris flows occurred around Umyeon Mountain and most of the debris flows were initiated by small slope failures. The effects of the precipitation that triggered the debris flows were analyzed as well. A landslide hazard map which considers slope gradient and aspect, strength of soil, hazard record, rainfall conditions, and vegetation, was constructed and compared with the initiation zones of debris flows. 相似文献
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Response of surface subtidal current to wind and outflow plume in the bay-shape estuary, which had been artificially made by the Samangeum reclamation dike with two sluices in the west coast of Korea, was examined using the ocean radar-derived current data obtained in the summer 2010. The southerly wind was dominant due to Asian summer monsoon and the outflow plume water was discharged by the gate operation of the Shinsi and Garyeok sluices separated by 11 km into the study area that are opened in a southwestward direction. The monthly-mean flow pattern consisted of the westward outflow currents around the two sluices, the along-dike currents between the two sluices and the northward currents in the outer bay. Based upon the complex correlations of subtidal current to wind and outflow jets we explained that the northward mean current in the outer bay be formed by both the southerly wind-driven current and the geostrophic current by mean pressure setup due to the Ekman transport and plume water accumulation in the inner bay, and the along-dike mean current may be induced by the southerly wind that generates on-dike currents in the central region of study area and leads to pressure setup toward the dike between the two sluices. Combination of outflow jets, wind and coastline configuration affects variations of subtidal surface current in the inner bay. Variability of subtidal current in the outer bay is dominated by wind variation. The southerly wind produced the northward current in the outer bay though the outflow plumes from the two sluices turned clockwise from the inner to the outer bay due to the geostrophic balance when the wind was calm. The wind factor was from 2% to 7% depending on the amount of freshwater outflow and wind speed. Occasionally, when plume water discharges were large and the southerly wind was stronger than 5 m/s, a large eddy with a closed loop current was produced off the Shinsi sluice. 相似文献
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Chan-Young Park Seung-Ho Park Choon-Woo Kim Jung-Keuk Kang Ki-Hyune Kim 《Marine Georesources & Geotechnology》1999,17(4):371-386
In order to develop the mineral resources contained in manganese nodules of the deep sea, the Korea Ocean Research & Development Institute (KORDI) has explored the area allocated by the United Nations in the Clarion-Clipperton Fracture Zone in the northeastern Pacific. During research cruises, the seabed surface was photographed every 30 s by the KORDI Deep Tow Imaging System (DTIS). Features such as the coverage and size distribution of manganese nodules on the photographs serve as the essential information to determine the potential mining areas. This article presents (semi)automatic procedures to extract the useful features from the photographs of the seabed surface using digital image processing techniques. The 35-mm films are first digitized by the film scanner. The depth information written on the film is then recognized to compensate for distortions due to nonuniform illumination. The nodule areas on the digitized image are recognized and separated from the background based on the characteristics of the nodules. The nodule coverage and distribution of nodule diameters are then calculated from the processed image. The proposed technique has been applied to sample photographs of the seabed surface. Experimental results indicate that the technique could be utilized as an efficient tool to process the massive collection of photographs of the seabed surface. 相似文献
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歧口凹陷西南缘是岩性油气藏发育区,尤其是沙一段下部发育湖相碳酸盐岩储层,是油气勘探开发的有利目的层段.利用岩心、薄片、扫描电镜等资料,分析沙一段下部碳酸盐岩储层的岩性、物性及储集空间特征.结果表明:研究区主要发育生物碎屑灰岩、鲕粒灰岩、泥晶灰岩和泥晶云岩,其中生物碎屑灰岩和鲕粒灰岩的物性最好,泥晶灰岩和泥晶云岩物性较差.优质储层是沉积作用、成岩作用和构造作用三者共同作用的结果,但储层的类型和规模主要受沉积相的控制,为预测有利储集相带提供依据. 相似文献
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Chan-Young Son Jong-Suk Kim Young-Il Moon Joo-Heon Lee 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(5):1147-1156
This study carried out a comparative analysis of the changes in tropical cyclone (TC) genesis, TC track, and TC intensity focusing on TCs that affected the Korean peninsula (KP) according to three evolutionary patterns (prolonged, abrupt and symmetric-decay) of the abnormal sea surface temperature in the Central-Pacific (CP) region. As a result of the analysis, the activity pattern of TCs was found to vary depending on the evolution patterns of the CP El Niño, and such changes appeared to result in clear variations in the regional rainfall in Korea. In the prolonged-decaying and symmetric-decaying years, the KP received considerable TC rainfall. On the other hand, in abrupt-decaying years, it was subtly affected by the TC rainfall. Although rather limited conditions and relatively short observation data were used to analyze the effects of the evolution pattern of the CP El Niño on TCs, the results can be used to quantitatively identify the spatial features of TCs affecting the KP. These results are expected to be helpful in managing the disaster risks in vulnerable areas, including plans to secure stable water resources in the basin, and in establishing effective and active measures to cope with natural disasters by extreme events over the KP. 相似文献
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