• 농업과학연구
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• 제46권1호
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• pp.205-217
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• 2019

The aim of this study was to identify land resources because food production and supply in North Korea have been at risk due to variations in its seasonal climate. More than three-fifths of the soils are locally derived from the weathering of granitic rocks or various kinds of schists developed from crystalline rocks. Well-developed reddish brown soils derived from limestone are found in the North Hwanghae province and in the southern part of the South Pyeongan province. Additionally, a narrow strip of similarly fertile land runs through the eastern seaboard of the Hamgyong and Kangwon Provinces. The loss of clay particles and organic matter are major causes of degradation in the soil physical and chemical properties in North Korea. 75% of the areas converted from forests became croplands, and 69% of the land converted to croplands came from forests. The net forest loss was quite small from the 1990s to the 2000s. However, deforestation in areas with a slightly lower elevation and gentler slope between 1997 and 2014 led to severe soil erosion resulting in a drastic change in the physical and chemical properties of the soil which influenced cropland stability and productivity. Therefore, the drastic changes in land cover as well as in the physical and chemical properties of the soil caused by various geographical features have seriously influenced the productivity of crops in North Korea.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.177-184
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• 2003

Numerical simulation on marine wind and sea surface elevation was carried out using both three-dimensional hydrostatic and non-hydrostatic models and a simple oceanic model from 0900 LST, August 13 to 0900 LST, August 15, 1995. As daytime easterly meso-scale sea-breeze from the eastern sea penetrates Kangnung city in the center part as basin and goes up along the slope of Mt. Taegullyang in the west, it confronts synoptic-scale westerly wind blowing over the top of the mountain at the mid of the eastern slope and then the resultant wind produces an upper level westerly return flow toward the East Sea. In a narrow band of weak surface wind within 10km of the coastal sea, wind stress is generally small, less than l${\times}$10E-2 Pa and it reaches 2 ${\times}$ 10E-2 Pa to the 35 km. Positive wind stress curl of 15 $\times$ 10E-5Pa $m^{-1}$ still exists in the same band and corresponds to the ascent of 70 em from the sea level. This is due to the generation of northerly wind driven current with a speed of 11 m $S^{-1}$ along the coast under the influence of south-easterly wind and makes an intrusion of warm waters from the southern sea into the northern coast, such as the East Korea Warm Current. On the other hand, even if nighttime downslope windstorm of 14m/s associated with both mountain wind and land-breeze produces the development of internal gravity waves with a hydraulic jump motion of air near the coastal inland surface, the surface wind in the coastal sea is relatively moderate south-westerly wind, resulting in moderate wind stress. Negative wind stress curl in the coast causes the subsidence of the sea surface of 15 em along the coast and south-westerly coastal surface wind drives alongshore south-easterly wind driven current, opposite to the daytime one. Then, it causes the intrusion of cold waters like the North Korea Cold Current in the northern coastal sea into the narrow band of the southern coastal sea. However, the band of positive wind stress curl at the distance of 30km away from the coast toward further offshore area can also cause the uprising of sea waters and the intrusion of warm waters from the southern sea toward the northern sea (northerly wind driven current), resulting in a counter-clockwise wind driven current. These clockwise and counter-clockwise currents much induce the formation of low clouds containing fog and drizzle in the coastal region.

• 자원환경지질
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• 제15권2호
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• pp.65-88
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• 1982

In the last ten years, marine geological and geophysical survey and research were conducted by Japanese, Russian and American scientists in the East Sea of Korea (Japan Sea). Many research results were published. However, regional research of the geology of the continental margin of the Korean Peninsula was not conducted. This study has made on attempt to classify submarine strata and stratigraphic boundaries. The study has revealed characters of submarine geology and structure. Isopach maps of each identified stratigraphic unit have been constructed as the results of this study. The study was conducted on the basis of analyses of marine seismic surveys carried out in the continental margin of the East Sea between Kangneung and Pohang. Three depositional basins were identified in the study area and they were named as, Mukho Basin, Hupo Basin and Pohang Basin. The Mukho Basin is developed in continental slope and shelf in the area between Kangneung and Samcheog. Quaternary and Pliocene sediments attain a maximum thickness of 900 m. Basement rocks are interpreted as granite and gneiss. They are correlated with granite-gneiss of the Taebaecksan Series of Pre-cambrian age and the Daebo granite of Jurassic age. The Hupo Basin is developed in the continental shelf between Uljin and Youngdeok. Quaternary and Pliocene sediments attain a maximum thickness of 600 m. Basement rocks were interpreted as granite and gneiss and they are correlated with metamorphic rocks of Pre-cambrian age and the Daebo granites, comprising the Ryongnam Massif. The Pohang Basin is developed in the area between Pohang and Gangu. This basin contains Miocene and older sediments. Basement rocks are not shown. Many faults are developed within the continental shelf and slope. These faults strike parallel with the coast line. A north-south direction is predominant in the southern study area. However, in the northern study area the faults strike north, and north-west. The faults are parallel to each other and are step faults down-thrown to the east or west, forming horst and graben structures which develop into sedimentary basins. Such faults caused the development of submarine banks along the boundary between the continental shelf and slope. This bank has acted as a barrier for deposition in the Hupo Basin. Paleozoic sedimentary rocks distributed widely in the adjacent land area are absent in the Mukho Basin. This suggests that the area of the basin was situated above the sea level until the Pliocene time. The study area contains Pliocene sediments in general. These sediments overlie the basement complex composed of metamorphic rocks, granites, Cretaceous (Kyongsang System) sedimentary rocks and Miocene sedimentary rocks. These facts lead to a conclusion that the continental shelf and slope of the study area were developed as a result of displacements along faults oriented parallel to the present coast line in the post Miocene time.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.142-142
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• 2022

Adjusting weather radar data is a prerequisite for its use in various hydrological studies. Effect of spatial variables are considered to adjust weather radar data in many of these researches. The existence of diverse topography in South Korea has increased the importance of analyzing these variables. In this study, some spatial variable like slope, elevation, aspect, distance from the sea, plan and profile curvature was considered. To investigate different topographic conditions, tried to use three radar station of Gwanaksan, Gwangdeoksan and Gudeoksan which are located in northwest, north and southeast of South Korea, respectively. To form the suitable fuzzy model and create the best membership functions of variables, ANFIS-PSO model was applied. After optimizing the model, the correlation coefficient and sensitivity of adjusted Quantitative Precipitation Estimation (QPE) based on spatial variables was calculated to find how variables work in adjusted QPE process. The results showed that the variable of elevation causes the most change in rainfall and consequently in the adjustment of radar data in model. Accordingly, the sensitivity ratio calculated for variables shows that with increasing rainfall duration, the effects of these variables on rainfall adjustment increase. The approach of this study, due to the simplicity and accuracy of this method, can be used to adjust the weather radar data and other required models.

• 한국지구과학회지
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• 제25권2호
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• pp.94-108
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• 2004

얼음골 주변의 지표면 변화에 따른 중규모 대기순환장에 미치는 효과를 보기위하여 수치실험을 실시하였다. 얼음골 남북 경사면에서 발생하는 순환장은 지형과 단파복사에 의한 영향으로 다르게 나타나며, 비대칭을 이룬다. 그리고 이러한 비대칭은 18시까지 계속된다. 야간의 경우, 도로건설에 따른 대기순환장의 차이는 크지 않다. 이것은 주간 단파 복사에 의한 현열플럭스가 감소하며, 현열플럭스외의 다른 요소는 크게 영향을 미치지 않는다는 것을 의미한다. 도로의 건설은 현열플러스의 증가와 관련되고, 주간의 경우, 지형에 의한 곡풍과 결합하여 도로가 없는 경우에 비하여 상승류가 강하여진다. 최대풍속은 4.67 m/s이다. 그리고 이때 도로의 위치역시 주요한 요인으로 작용한다.

• The Korean Journal of Ecology
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• 제20권5호
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• pp.329-337
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• 1997

Study of population density and biomass of soil microarthropods in soil, herbaceous leaf litter and wood leaf litter was conducted at 4 sites with different flora in Mt. Jumbong, a nature reserve area, in Korea from Aug. 1994 to May 1996. Total 47, 849 individuals of soil microarthropods in soil were collected and identified into 6 different classes, and 16 orders. The composition, densities, and dominant group of soil microarthropods were different among 4 sampling sites. Collembola was the most abundant group with 50.7% at South-facing slope and 50.6% at the North-facing slope. But Acari was the most abundant group with 49.8% at Altitude 900m site and 47.7% at Altitude 1100m site. Two group ranged 87-95% of total individuals. A/C ratio was less than 1.0 at 4 sampling sites during the all sampling seasons. As a result of biomass evaluation, rato of Acari was decreased but ratio of Diplopoda, coleoptera, Araneae, Diptera and Chilopoda was increased. About 70% of total orders and densities were found in less than 5cm soil depth. The composition, densities, and dominant group of soil microarthropods were different among soil, herbaceous litter and wood litter. Collembola was the most abundant group in herbaceous and wood litter. A/C ratio was less than 1.0 in litter during the sampling seasons. As a result of biomass evaluation in litter, ration of Araneae and Collembola was very high, but ratio of Acari was low.

• 한국지역지리학회지
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• 제17권3호
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• pp.348-356
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• 2011

현재까지의 조산운동 기록에 의하면 백두산은 언젠가는 분화가 얼어날 것이다. 본 연구는 백두산 화산폭발 시뮬레이션을 통해 용암류와 화산재가 미치는 영향범위를 예측하고자 하였다. 시뮬레이션은 화산폭발지수 7, 계절은 가을에서 봄에 분화가 일어날 것을 가정하여 적용하였다. 시뮬레이션 결과 용암은 중국쪽 사면으로 흘렀고, 화산재는 북한지역으로 확산되었다. 화산재는 9시간 만에 울릉도 지역까지 확산되었다. 북한의 27개 시 군 행정구역 중에서 61개 도시와 마을이 화산재의 영향을 받는 것으로 예측되었으며, 많은 양의 화산재가 농경지, 도시지역, 산림지역에 퇴적되었다. 연구결과는 북한에서 재난 대비, 남 북 및 중국과의 공동 연구를 위한 정보로 활용될 수 있기를 기대한다.

• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.64-73
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• 2012

The angle of solar panels is calculated using solar radiation model for the efficient solar power generation. In ideal state, the time of maximum solar radiation is represented from 12:08 to 12:40 during a year at Gangneung and it save rage time is12:23. The maximum solar radiation is 1012$W/m^2$ and 708$W/m^2$ inc lear sky and cloudy sky, respectively. Solar radiation is more sensitive to North-South (N-S) slope angle than East-West (E-W) azimuth angle. Daily solar radiation on optimum angle of solar panel is higher than that on horizontal surface except for 90 days during summer. In order to apply to the real atmosphere, the TMY (typical meteorological Year) data which obtained from the 22 solar sites operated by KMA(Korea Meteorological Administration) during 11 years(2000 to 2010) is used as the input data of solar radiation model. The distribution of calculated solar radiation is similar to the observation, except in Andong, where it is overestimated, and in Mokpo and Heuksando, where it is underestimated. Statistical analysis is performed on calculated and observed monthly solar radiation on horizontal surface, and the calculation is overestimated from the observation. Correlationis 0.95 and RMSE (Root Mean Square Error) is10.81 MJ. The result shows that optimum N-S slope angles of solar panel are about $2^{\circ}$ lower than station latitude, but E-W slope angles are lower than ${\pm}1^{\circ}$. There are three types of solar panels: horizontal, fixed with optimum slope angle, and panels with tracker system. The energy efficiencies are on average 20% higher on fixed solar panel and 60% higher on tracker solar panel than compared to the horizontal solar panel, respectively.

• 한국수자원학회논문집
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• 제44권3호
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• pp.179-188
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• 2011

본 연구에서는 강원도의 지역인자를 이용하여 지점 강우량과 면적 강우량의 관계를 파악하였다. 강원도는 면적의 대부분이 산지로 형성된 산악지형이며 태백산맥 동쪽 (영동지방)은 경사가 급하여 해안평야의 발달이 취약하고, 태백산맥 서쪽 (영서지방)은 경사가 완만하여 남 북한강의 대하천이 발달하고 곳곳에 산지가 분포되어 있는 복잡한 지형이다. 강원도 지역의 확률강우량 공간분포를 산정하기 위하여 강원도 인근의 기상관측소 66개소의 자료를 이용하였으며, 강우의 공간분포를 분석하기위하여 PRISM을 적용하였다. 적용결과를 도시한 결과 지형 조건 (고도 및 경사)과 지역적인 조건(영동 및 영서지방, 북한강 지역 및 남한강 지역)에 따라 적정하게 분포된 것으로 나타났으며, 교차검증을 통한 분석결과 RRBIAS 및 RRMSE가 모두 0.1 이하의 낮은 값을 나타내어 PRISM 분석이 적정하게 수행되었음을 알 수 있었다. 따라서 본 연구에서 적용한 PRISM 모형이 강원도 내 확률강우량의 공간분포를 예측하는데 유용한 것으로 판단된다.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.219-228
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• 2002

Based on the five-year (October 1992 through September 1997) Topex/Poseidon altimeter measurements, we describe the statistical characteristics of the eddy variability in the East Sea in terms of sea surface height anomaly, slope variability, and eddy kinetic energy (EKE). The sea surface height anomalies in the East Sea are produced with standard corrections from Topex/Poseidon measurements. In order to eliminate the high frequency noise in the sea surface height anomaly data, the alongtrack height anomaly data was filtered by about 40 km low-pass Lanczos filter based on Strub et al. (1997) and Kelly et a1. (1998). We find that there exists a distinct spatial contrast of high eddy variability in the south and low eddy energy in the north, bordering the Polar Front. In the northwestern area $(north\;of\;39^{\circ}N\;and\;west\;of\;133^{\circ}E)$ from the Polar Front where the eddies frequently appear, the EKE is also considerabel. The high kinetic energy in the southern East Sea reveals a close connection with the paths of the Tsushima Warm Current, suggesting that the high variability in the south is mainly generated by the baroclinic instability process of the Tsushima Warm Current. This finding is supported by other studies (Fu and Zlontnicki, 1989; Stammer, 1997) wh.ch have shown the strong eddy energy coupled in the major current system. The monthly variation of the EKE in both areas of high and low eddy variability shows a strong seasonality of a high eddy kinetic energy from October to February and a relatively low one from March to September. The sequential pattern of wind stress curl shows resemblance with those of monthly and seasonal EKE and the two sequences have a correlation of 0.82 and 0.67, respectively, providing an evidence that wind stress curl can be the possible forcing for the monthly and seasonal variation of the EKE in the East Sea. The seasonality of the EKE also seems to correlate with the seasonality of the Tsushima Warm Current. There also exists the large spatial and interannual variabilities in the EKE.