Quantities,composition, and sources of beach debris in Korea from the results of nationwide monitoring

This study assessed the levels of marine debris pollution and identified its main sources in Korea. The surveys were bimonthly conducted by NGO leaders and volunteers on 20 beaches from March 2008 to November 2009. The quantities of marine debris were estimated at 480.9 (±267.7) count ⋅ 100 m⁻¹ for number, 86.5 (±78.6) kg ⋅ 100 m⁻¹ for weight, and 0.48 (±0.38) m³ ⋅ 100 m⁻¹ for volume. The level of marine debris pollution on the Korean beaches was comparable to that in the coastal areas of the North Atlantic ocean and South Africa. Plastics and styrofoam occupied the majority of debris composition in terms of number (66.7%) and volume (62.3%). The main sources of debris were fishing activities including commercial fisheries and marine aquaculture (51.3%). Especially styrofoam buoy from aquaculture was the biggest contributor to marine debris pollution on these beaches.     

GIS-based groundwater potential mapping using artificial neural network and support vector machine models: the case of Boryeong city in Korea

Groundwater productivity-potential (GPP) was analysed using the data mining models of an artificial neural network (ANN) and a support vector machine (SVM) in Boryeong city, Korea. The groundwater-productivity data with specific capacity (SPC) is strongly related to hydrogeological factors, and hence the relation may allow for groundwater potential mapping from hydrogeological factors through the ANN and SVM models. A back-propagation algorithm was used for the ANN model while a polynomial kernel was adopted for the SVM model. For the validation of the GPP maps generated from the ANN and SVM models, the area-under-the-curve analysis was performed using the SPC values of well data. The accuracies achieved from the ANN and SVM models are about 83.57 and 80.83%, respectively. It proves that the ANN and SVM models will be highly conducive to developing useful groundwater resources.     

韩国的地震监测与研究概况

１９９６年１月２８日－２月６日中国地震代表团一行１３人次首次访问韩国并参加第一届中韩数字地震学研讨会。文章概要介绍了韩国的地震预测、地震目录研究、地震活动性研究、地震监测与研究计划。     

Conodonts from the Sesong Slate and Hwajeol Formation (Guzhangian to Furongian) in the Taebaeksan Basin, Korea

Abundant conodont elements have been recovered from the Hwajeol Formation, to allow five zones to be erected: Proconodontus, Eoconodontus notchpeakensis, Cambrooistodus minutus, Cordylodus proavus, and Fryxellodontus inornatus-Monocostodus sevierensis-Semiacontiodus lavadamensis zones, in ascending order. More confident biozones are recognized in the Sesong Slate and lower Hwajeol Formation in the Makgol section, a part of the southern limb of the Baekunsan syncline, Taebaeksan Basin, Korea, especially focusing on the conodont biostratigraphic boundary of two units, and the subdivision potential of the previous "Proconodontus Zone", lowermost biozone of the Hwajeol Formation. Similarly, only a few conodont elements recovered from upper 14.5 m interval, namely the Furongian portion of the Sesong Slate, in the Makgol section did not allow erection of a biozone. Nevertheless, this part of the unit plus the basal 2.5 m interval of the Hwajeol Formation is characterized by the occurrence of Prooneotodus rotundatus(Druce and Jones), Teridontus nakamurai(Nogami), Phakelodus elongatus(An) and Phakelodus tenuis Müller. This interval marks the early Furongian "Prooneotodus rotundatus Zone". The rest of the measured section yielded relatively abundant conodonts, so three conodont biozones are proposed, based on the successive appearance of key species: Proconodontus tenuiserratus, Proconodontus posterocostatus, and Proconodontus muelleri zones, in ascending order, and thus allowing subdivision of the previous "Proconodontus Zone". The four conodont biozones are correlated with the relevant biozones of North and South China, and North America.     

Surface and upper-level features associated with wintertime cold surge outbreaks in South Korea

The surface and upper-level features associated with a sharp drop of wintertime daily temperature over South Korea is investigated in this study. This sharp drop in daily temperature is called a cold surge and is one of the most hazardous weather phenomena in East Asian winters. An upper-level baroclinic wave of 60°wavelength propagating eastward at a phase speed of 12°longitude per day across the continent of northern China from the west of Lake Baikal toward the eastern coast of China causes the outbreak of cold air over South Korea. The cooling associated with the upper-level baroclinic wave is found at all altitudes under the geopotential height-fall center near the tropopause. The development in the ridge seems to derive the early evolution of the eastward-propagating sinusoidal wave, whereas the trough is connected directly with the tropospheric temperature-drop. An enhancement of the wintertime East Asian jet stream after the outbreak of a cold surge is a response to the steep temperature gradient associated with the developing baroclinic wave.     

山东地区与朝鲜半岛地区地震的相关性

系统分析了山东及朝鲜半岛地区历史地震记载的情况和特点，分析表明，两区的历史与现代地震资料有较强的互补性强震具有同步涨落，遥相呼应的相关性，这种相关性天时间上具有步进次序关系，受高层次地震活动韵所制约；空间上则有相近纬度优势呼应现象。初步认为，这两个地区地震的相关现象与共同受到西太平洋消减带的俯冲推挤作用有关。     

Local Meteorological and Synoptic Characteristics of Fogs Formed over Incheon International Airport in the West Coast of Korea

Fogs observed over Incheon international airport (IIA) in the westcoast of Korea from January 2002 to August 2006 are classified into categoriesof coastal fog, cold sea fog, and warm sea fog based on the areal extent of thefogs and the difference between the air temperature (T) and the SST, i.e.,cold sea fog if TSST = T-SST>0^oC and warm sea fog if TSST<0^oC. The numbers of coastal, cold, and warm sea fog casesare 64, 26, and 9. Coastal fogs form most frequently in winter, while cold seafogs occur mostly in summer and warm sea fogs are observed from January to Maybut not in November and December. On average the air gets colder by1.6^oC during the three hours leading up to the coastal fogformation, and an additional cooling of 1.1^oC occurs during thefog. The change in the dew point temperature (T_d) is minimal exceptduring the fog (0.6^oC). Decreases in T for the cold and warmsea fogs are relatively smaller. The average T_d is higher than SSTduring the cold sea fog periods but this T_d is more than4^oC higher than that for the corresponding non-fog days,suggesting that cold sea fogs be formed by the cooling of already humid air(i.e., T_d>SST). Increases of T_d are significant during thewarm sea fog periods (1.4^oC), implying that efficient moisturesupply is essential to warm sea fog formation. Four major synoptic patterns areidentified in association with the observed fogs. The most frequent is a northPacific high that accounts for 38% of cases. Surface or upper inversions arepresent in 77%, 69%, and 81% of the fog periods for coastal, cold, andwarm sea fogs, respectively.     

Crop classification and acreage estimation in North Korea using phenology features

In North Korea, reliable and timely information on crop acreage and spatial distribution is hard to obtain. In this study, we developed a fast and robust method to estimate crop acreage in North Korea using time-series normalized difference vegetation index (NDVI) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) data. We proposed a method to identify crop type based on NDVI phenology features using data collected in other areas with similar agri-environmental conditions to mitigate the shortage of ground truth data. Eventually the classification map (MODIScrop) was assessed using the Food and Agriculture Organization (FAO) statistical data and high-resolution crop classification maps derived from one Landsat scene (LScrop). The Pareto boundary method was used to assess the accuracy and crop distribution of the MODIScrop maps. Results showed that acreage derived from the MODIScrop maps was generally consistent with that reported in the FAO data (a relative error <4.1% for rice and <6.1% for maize, and <9.0% for soybean except for in 2004, 2008, and 2009) and the maps derived from the LScrop (a relative error about 5% in 2013, and 7% in 2008 and 2014). The classification accuracy reached 74.4%, 69.8%, and 73.1% of the areas covered by the Landsat images in 2008, 2013, and 2014, respectively. This indicates that features derived from NDVI profiles were able to characterize major crops, and the approaches developed in this study are feasible for crop mapping and acreage estimation in regions with limited ground truth data.     

韩国和马来西亚建立本国三维地心大地坐标系统的进展

介绍了韩国大地坐标系统的沿革 ,阐述了近年来韩国建立本国三维地心坐标系的工作和进展。为了对比韩国 ,简约介绍了马来西亚等国在这方面的新进展