• 한국해양학회지
• /
• 제6권2호
• /
• pp.92-98
• /
• 1971

본고는 지난 12년동안 한국연안에 내습한 태풍 및 각 검조소에 출현한 매년의 최고 이상고조와 1970.8.29∼9.2에 있었던 태풍 빌리호 내습시 남 서해안의 각 검조소에서 얻은 자료에 의하여 해면변화에 대한 사례조사를 시도한 것이다. 한국연안은 매년 빈번한 기상교란 (태풍, 저기압등) 에 의하여 이상고조 또는 기상해일현상이 발생, 항만이나 연안지대에서는 적지 않은 피해를 받고 있으나 이에 관한 조사는 전혀 없었으며, 이후 연안지대의 고도이용이나 연안방재를 위하여 먼저 정확한 사례조사가 필요하다고 본다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.309-312
• /
• 2008

The advent of high resolution products of surface wind and temperature derived by satellite data has permitted us to investigate ocean and atmosphere interaction studies in detail. Especially the Kuroshio extension region of the western North Pacific is considered to be a key area for such studies. We have constructed gridded products of surface wind/wind stress over the world ocean using satellite scatterometer (Qscat/SeaWinds), available as the Japanese Ocean Flux data sets with Use of Remote sensing Observation (J-OFURO). Using new data based on improved algorithm which have been recently delivered, we are reconstructing gridded product with higher spatial resolution. Intercomparison of this product with the previous one reveals that there are some discrepancies between them in short-period and high wind-speed ranges especially in the westerly wind region. The products are validated by not only comparisons with in-situ measurement data by mooring buoys such as TAO/TRITON in the tropical Pacific and the Kuroshio Extension Observation (KEO) buoys, but also intercomparison with numerical weather prediction model (NWPM) products (the NRA-1 and 2). Our products have much smaller mean difference in the study areas than the NWPM ones, meaning higher reliability compared with the NWPM products. Using the high resolution products together with sea surface temperature (SST) data, we examine a new type of relationship between the lower atmosphere and upper ocean in the Kuroshio Extension region. It is suggested that the spatial relation between the wind speed and SST depends upon, more or less, the surrounding oceanic condition.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2003년도 International Symposium on Clean Environment
• /
• pp.19-26
• /
• 2003

The dispersion of recycled particulates in the complex coastal terrain containing Kangnung city, Korea was investigated using a three-dimensional non-hydrostatic numerical model and lagrangian particle model (or random walk model). The results show that particulates at the surface of the city that float to the top of thermal internal boundary layer (TIBL) are then transported along the eastern slope of the mountains with the passage of sea breeze and nearly reach the top of the mountains. Those particulates then disperse eastward at this upper level over the coastal sea and finally spread out over the open sea. Total suspended particulate (TSP) concentration near the surface of Kangnung city is very low. At night, synoptic scale westerly winds intensify due to the combined effect of the synoptic scale wind and land breeze descending the eastern slope of the mountains toward the coast and further seaward. This increase in speed causes development of internal gravity waves and a hydraulic jump up to a height of about 1km above the surface over the city. Particulate matter near the top of the mountains also descends the eastern slope of the mountains during the day, reaching the central city area and merges near the surface inside the nocturnal surface inversion layer (NSIL) with a maximum ground level concentration of TSP occurring at 0300 LST. Some particulates were dispersed following the propagation area of internal gravity waves and others in the NSIL are transported eastward to the coastal sea surface, aided by the land breeze. The following morning, particulates dispersed over the coastal sea from the previous night, tend to return to the coastal city of Kangnung with the sea breeze, developing a recycling process and combine with emitted surface particulates during the morning. These processes result in much higher TSP concentration. In the late morning, those particulates float to the top of the TIBL by the intrusion of the sea breeze and the ground level TSP concentration in the city subsequently decreases.

• 한국환경과학회지
• /
• 제25권1호
• /
• pp.107-125
• /
• 2016

Long-term variations of $PM_{10}$ and the characteristics of local meteorology related to its concentration changes were analyzed at 4 air quality sites (Ido-dong, Yeon-dong, Donghong-dong, and Gosan) in Jeju during two different periods, such as PI (2001-2006) and PII (2007-2013), over a 13-year period. Overall, the long-term trend of $PM_{10}$ was very slightly downward during the whole study period, while the high $PM_{10}$ concentrations in PII were observed more frequently than those in PI. The concentration variations of $PM_{10}$ during the study period was clarified in correlation between $PM_{10}$ and meteorological variables, e.g. the low (high) $PM_{10}$ concentration with large (small) precipitation or high (low) radiation and in part high $PM_{10}$ concentrations (especially, Donghong-dong and Gosan) with strong wind speed and the westerly/northwesterly winds. This was likely to be caused by the transport effect (from the polluted regions of China) rather than the contribution of local emission sources. The $PM_{10}$ concentrations in "Asian dust" and "Haze" weather types were higher, whereas those in "Precipitation", "Fog", and "Thunder and Lighting" weather types were lower. The contribution of long-range transport to the observed $PM_{10}$ levels in the urban center (Ido-dong, Yeon-dong, and Donghong-dong), if estimated by comparison to the data of the background site (Gosan), was found to explain about 80% (on average) of its input.

• 한국환경과학회지
• /
• 제26권12호
• /
• pp.1375-1387
• /
• 2017

In order to investigate the $PM_{10}$ concentration trend and its characteristics over five different sub area in Busan from 2013 to 2015, data analysis with considering air flow distribution according to its topography was carried out using statistical methodology. The annual mean concentrations of $PM_{10}$ in Busan tend to decrease from $49.6{\mu}g/m^3$ in 2013 to $46.9{\mu}g/m^3$ in 2015. The monthly mean concentrations value of $PM_{10}$ were high during spring season, from March to May, and low during summer and fall due to frequent rain events. The concentration of $PM_{10}$ was the highest in five different sub-area in Busan. High concentration episodes over 90 percentile of daily $PM_{10}$ concentration were strongly associated with mean daily wind speed, and often occurred when the westerly wind or southwesterly wind were dominant. Regardless of wind direction, the highest correlation of $PM_{10}$ concentrations was observed between eastern and southern regions, which were geographically close to each other, and the lowest in the western and eastern regions blocked by mountains. Wind flow along the complex terrain in Busan is also one of the predominant factors to understand the temporal variation of $PM_{10}$ concentrations.

• 한국지구과학회지
• /
• 제30권5호
• /
• pp.529-549
• /
• 2009

In 2007, just after the recession of the Changma, anomalously long rainy period (from July 30 to August 15) occurred in Korea. To identify the cause of the sustained rainy period, we performed synoptic analysis and the associated air motions. The behavior of each air parcel trajectory associated with atmospheric motion was then investigated. As a result, three particular phenomena occurring at latitudes lower than $40^{\circ}N$ were discovered. First, a mass of relatively cold air, referred to as E, made a deep intrusion from $20^{\circ}N$ to $60^{\circ}N$. Second, this intrusion was accompanied by another mass of air called dE. It was colder and drier than E and originated from the mid-troposphere over the tropical ocean. Third, dE and E rotated clockwise three times over a period of 17 days over the Northwestern Pacific and blocked the westerly waves imbedded in the zonal flow from propagating. Two additional phenomena were observed at latitudes higher than $40^{\circ}N$. First, the cold core system, while approaching from the west with low geopotential values at its center, was stagnated over Shanxi China. It enhanced the northward intrusion of dE and E, and then diminished. The subsequent low system showed similar evolution as the first one. Second, a warm core anticyclone was formed over Lake Baikal, blocking the westerlies for 13 days and contributed to the persistent northward incursion of warm moist air. Moreover, a horizontally extended intrusion of upper level clouds from the tropics to $50^{\circ}N$, which may be interpreted as a tropical plume, was found around the end of the period (from August 12 to 15, 2007) with successive tropical nights over Korea.

• Ocean and Polar Research
• /
• 제36권2호
• /
• pp.87-101
• /
• 2014

Recently, more attention has been paid to the geomorphological changes in the Nakdong River Estuary, because those changes are caused by artificial activities including weirs, reclamation and construction. In order to analyze quantitatively the recent geomorphological variability in the Nakdong River Estuary, we surveyed the depth and elevation of submarine topography near Jinwoodo and Sinjado from March 2007 to February 2012. A statistical method (based on Digital Shoreline Analysis System) and an Empirical Orthogonal Functions method were used to evaluate the morphological changes. According to the statistical variables (DCE, NDC, EPR, LRR), the highest amount and rate of accumulation were recorded around the Gadeokdo whereas the greatest amount of erosion appeared around the coast off the eastern part of Sinjado. In particular, a dynamic variation of morphology was clearly observed in the vicinity of the sub-tidal channel located between Jinwoodo and Sinjado, which seems to be attributable to channel migration. As a result of the EOF method, the first mode (48.7%) is most closely related to the pattern of morphological variability that might be associated with the westerly movement of sediment by longshore current. The spatial variability of the second mode (16.6%) was high in the shoreface of Sinjado, showing a 4-year periodicity of temporal variability. The strong correlation (coefficient 0.73) between the time coefficient and suspended sediment discharge from Nakdong River emphasizes the role of sediment discharge to deposition in this area. The spatial variability of the third mode (11.3%) was distributed mainly around the coast off the eastern part of Sinjado, which is related to the movement of the coastline of Sinjado. Based on the last 5 year's data, our results suggest that the study area is characterized on the whole by a depositional pattern, but the extent of sedimentation is different locally.

• 한국항공우주학회지
• /
• 제42권6호
• /
• pp.468-477
• /
• 2014

본 연구에서는 태양광 고고도 무인항공기가 어떻게 태양광 에너지만을 이용해서 지상에서 이륙, 상승비행을 하여 임무고도인 18 km 지점까지 도달할 수 있는지에 관한 연구를 수행하였다. 주익면적 $35.98m^2$와 가로세로비 25의 글라이더 형태의 항공기가 기준 항공기 형상으로 사용되었다. 미국 나사의 공개 프로그램인 OpenVSP와 XFLR5을 사용하여 형상변수 및 양력계수와 항력계수를 계산하였으며, 태양광으로부터의 가용에너지와 상승비행에 필요한 에너지 균형을 통해 항공기의 상승비행을 예측하였다. 각 고도에서 비행속도를 최소화하여 최소시간 상승비행이 가능하도록 하였고 이륙시간에 따른 임무고도 도달까지의 총소요시간과 소모되는 에너지량을 예측하였다. 또한 편서풍과 비행속도에 의한 항공기의 이동거리를 계산하였다.

• Journal of Korean Society for Atmospheric Environment
• /
• 제19권E4호
• /
• pp.177-186
• /
• 2003

The total of 1,454 aerosol samples were collected by high volume tape sampler at the Gosan Site in Jeju Island from 1992 to 1999, and the major water-soluble ionic components were chemically analyzed. The mean concentrations of nss-S $O_4$$^{2-}$, N $H_4$$^{＋}$, and N $O_3$$^{[-10]}$ showed high values, which were 6.73, 1.45, and 1.45 ${\mu}{\textrm}{m}$/㎥, respectively, while $Ca^{2+}$ and $K^{+}$ concentrations were low with the values of 0.49 and 0.42 $\mu\textrm{g}$/㎥. The concentrations of most components increased in spring but decreased in summer, especially with the remarkable increase of $Ca^{2+}$ and N $O_3$$^{[-10]}$ concentrations in spring. The seasonal comparison of nss-S $O_4$$^{2-}$ concentrations showed higher values with the order of spring > fall 〉 winter〉 summer, but spring 〉 winter〉 fall 〉 summer for N $O_3$$^{[-10]}$ Meanwhile, the concentration levels of N $a^{+}$ and C $l^{[-10]}$ increased more in winter season. According to the investigation of wind direction effect, the concentrations of most aerosol ionic components showed higher values consistently at the westerly and northerly wind conditions. Based on the factor analysis, the atmospheric aerosols in the Gosan Site are considered to be largely affected by marine sources, followed by anthropogenic and soil sources.urces..

• Asian Journal of Atmospheric Environment
• /
• 제7권4호
• /
• pp.217-226
• /
• 2013

The collection of TSP and $PM_{2.5}$ aerosols has been made at the Gosan Site of Jeju Island during 2008-2011, and their ionic and elemental species were analyzed, in order to examine the seasonal variation and characteristics of aerosol compositions. The anthropogenic components ($NH_4{^+}$, $nss-SO_4{^{2-}}$, $NO_3{^-}$, S, Zn, Pb) and the soil components ($nss-Ca^{2+}$, Al, Fe, Ca) showed high concentrations in spring as the prevailing westerly wind, but the concentrations of the sea-salt components ($Na^+$, $Cl^-$) were high in winter. In TSP, the neutralization by $NH_3$ increased in summer, but the neutralization by $CaCO_3$ increased in spring and fall seasons. The organic acids ($HCOO^-$, $CH_3COO^-$) contributed to the acidification of the aerosols by only 5.0%, so the acidification could be mostly contributed by the inorganic acids ($SO_4{^{2-}}$, $NO_3{^-}$). From the examination of the source origins by factor analysis, the compositions of TSP were influenced by the order of soil > anthropogenic > marine, on the other hand, those of $PM_{2.5}$ were by the order of anthropogenic > marine > soil. The backward trajectory analyses showed that the concentrations of $NH_4{^+}$, $nss-SO_4{^{2-}}$, $NO_3{^-}$ and $nss-Ca^{2+}$ increased highly when the air masses had moved from China continent into Gosan area of Jeju Island.