• 대기
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• 제17권3호
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• pp.241-253
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• 2007

This paper investigates summer precipitation change in East Asia according to switching surface boundary condition over South Korea and Shantung. Simulations are carried out by ECHO-G/S for 20 years (1980-1999). Surface condition over both areas in ECHO-G/S is represented by ocean (OCN experiment). In OCN experiment, the summer precipitation is considerably underestimated around the Korean peninsula (the dry region) and overestimated over the eastern Tibetan Plateau (the wet region). It may be related that the lack of the heat sources from the unrealistically prescribed land-sea mask weakens northward expansion of rainband and the development of convective precipitation. Moreover the simulated rainband retreats before June in connection with the early genesis of summer monsoon circulation. The systematic bias of the summer precipitation over the dry and wet regions are reduced comparing with the OCN experiment when the land-sea masks over South Korea and Shantung are realistically considered as land (LND experiment). These improvements can be explained by the thermodynamical dissimilarity between land and ocean. Enhanced warming by switching the areas from sea to land has led to develop the thermal low over Yellow Sea with the cyclonic circulation. Thus, this cyclonic circulation supports moistures from the south to the dry region and blocks to the wet region. The heat transport from the land surface to atmosphere plays a key role in the developing convective precipitation in local scale and maintaining the precipitation and the rainband. Therefore, this results indicate that the design of the realistic land-sea distribution is required for the accurate simulation of the regional precipitation.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.202-210
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• 2019

The obstacles modeling is a fundamental and significant issue for path planning and automatic navigation of Unmanned Surface Vehicle (USV). In this study, we propose a novel obstacles modeling method based on high resolution satellite images. It involves two main steps: extraction of obstacle features and construction of convex hulls. To extract the obstacle features, a series of operations such as sea-land segmentation, obstacles details enhancement, and morphological transformations are applied. Furthermore, an efficient algorithm is proposed to mask the obstacles into convex hulls, which mainly includes the cluster analysis of obstacles area and the determination rules of edge points. Experimental results demonstrate that the models achieved by the proposed method and the manual have high similarity. As an application, the model is used to find the optimal path for USV. The study shows that the obstacles modeling method is feasible, and it can be applied to USV path planning.

• 한국정보통신학회논문지
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• 제9권8호
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• pp.1787-1792
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• 2005

원격탐사와 GIS의 접목은 해안정보와 지리정보 뿐만 아니라 교통정보 등에 많이 이용되고 있다. 본 연구는 10m급 중해상도를 가지는 SPOT 위성영상으로 LPF(Low Pass Filtering) 기법으로 해안지역의 섬 경계 추출에 관한 연구이다. 연구대상지역은 남해지역으로 원격탐사기법으로 해안지역에 존재하는 섬을 검출하기 위해 LPT를 적용한 후 Sobel 연산자로 경계검출 한 후 GIS를 활용하여 백터자료를 구축하였다. 분석결과 5${\times}$5 convolution mask를 사용하여 섬 경계 추출하는 것이 가장 효과적인 것으로 나타났다. 본 연구를 바탕으로 배타적 경계수역에서 발생할 해양분쟁에서 과학적이고 합리적인 근거자료의 제시가 가능할 것으로 판단된다.