• 한국대기환경학회지
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• 제25권6호
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• pp.481-492
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• 2009

The characteristic of cold water by upwelling in the southeast of the Korean Peninsula and the effect of sea breeze in this region are investigated. The coastal upwelling around the southeast coast of the Korea Peninsula is analyzed by using Coastal Oceanographic Data statistical analyses for 5 years were carried out. The period of an cold water event, on the average, was observed southwesterly wind events. The analysis suggests that strong and persistent southwesterly winds in period of an cold water play an important role of bring the moisture to the surface, generating persistent cyclone as jangma. In order to investigate the effect of cold water on sea breeze, we considered two case. First, Exp. 1 is not occurred coastal upwelling on sea breeze. Second, Exp. 2 is occurred cold water on sea breeze. Two experiments were completed separately to the effects of cold water by upwelling. The results show the sea breeze is stronger in Exp. 2, when the cold water occurs, and weaker in Exp. 1, when there is no cold water. In order to verify the effect of the sea breeze on the cold water by upwelling, on the intensification and change of direction of the prevailing wind, the sea breeze effectively intensify cold water condition.

• 한국수산과학회지
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• 제31권3호
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• pp.359-371
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• 1998

감포-울기 연안에서 1987년부터 1994년까지 일어난 여름철 냉수대 현상을 수산진흥원의 연안정지 수온 관측치와 위성에 의한 해표면 사진, 그리고 SSM/I에 의한 해상풍 자료를 이용하여 연구하였다. 남서풍에 의한 냉수대의 반응 시간은 하루나 이틀정도로 아주 짧았고 냉수대는 울릉도 근해까지 세력을 확장하였다. 연구기간 8년중 남서풍 이벤트는 총 61회였는데 그 중 $80\%$의 경우 수온이 $1^{\circ}C$ 이상 떨어졌다. 바람합력과 최대하강온도와의 상관관계는 0.6으로 비교적 높았으며, 바람이 이 해역의 냉수대 발생 주원인으로 밝혀졌다. 감포 앞 해상에서 급격히 변하는 해저지형과 포텐셜 와도 보존 법칙에 의해 해안선과 분리되어 외해로 향하는 동한난류의 영향도 감포-울기 연안의 냉수대가 자주 출현하는 원인인 것으로 연구되었다.

• 대기
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• 제20권3호
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• pp.343-353
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• 2010

A regional wind network with complex surface conditions must be designed with sufficient space and time resolution to resolve the local circulations. In this study, the spatial variations of the wind field observed in the Seoul and Jeju regional networks were evaluated in terms of annual, seasons, and months to assess the spatial homogeneity of wind fields within the regional networks. The coherency of the wind field as a function of separation distance between stations indicated that significant coherency was sometimes not captured by the network, as inferred by low correlations between adjacent stations. A meso-velocity scale was defined in terms of the spatial variability of the wind within the network. This problem is predictably most significant with weak winds, dull prevailing wind, clear skies and significant topography. The relatively small correlations between stations imply that the wind at a given point cannot be estimated by interpolating winds from the nearest stations. For the Seoul and Jeju regional network, the meso-velocity scale has typically a same order of magnitude as the speed of the network averaged wind, revealing the large spatial variability of the Jeju network station imply topography and weather. Significant scatter in the relationship between spatial variability of the wind field and the wind speed is thought to be related to thermally-generated flows. The magnitude of the mesovelocity scale was significantly different along separation distance between stations, wind speed, intensity of prevailing wind, clear and cloudy conditions, topography. Resultant wind vectors indicate much different flow patterns along condition of contributing factors. As a result, the careful considerations on contributing factors such as prevailing wind in season, weather, and complex surface conditions with topography and land/sea contrast are required to assess the spatial variations of wind field on a regional network. The results in the spatial variation from the mesovelocity scale are useful to represent the characteristics of regional wind speed including lower surface conditions over the grid scale of large scale atmospheric model.

• ALGAE
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• 제28권3호
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• pp.281-288
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• 2013

Photosynthetic carbon fixation regulates air-sea $CO_2$ fluxes in the waters of coral reefs. However, little has been documented on the effects of solar UV radiation (UVR, 280-400 nm) upon photosynthetic behaviors of phytoplankton dwelling in these ecosystems. In order to evaluate the aforesaid, surface dwelling tropical coral reef phytoplankton assemblages collected from the South China Sea were exposed to solar radiation (i.e., photosynthetically active radiation [PAR] + UV radiation A [UVA] + UV radiation B [UVB], 280-700 nm; PAR + UVA, 320-700 nm; and PAR, 400-700 nm) under static or simulated-mixing conditions. Under the static condition, UVA and UVB significantly reduced the carbon fixation with the maximum of 22.4 and 15.3%, respectively; while lower UVR-related photosynthetic inhibition was observed in case of phytoplankton samples being subjected to mixing. At a moderate level of mixing (i.e., circulation time 80 min), the UVA and UVB caused inhibition were lowered by 52.1 and 79.6%, respectively. Based on this it could be stated that vertical mixing induced by winds and/or tides in the natural environments could reduce the inhibitory effect of solar UVR on phytoplankton productivity in the coral reefs water.

• 한국해양공학회지
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• 제34권1호
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• pp.26-36
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• 2020

An extreme value analysis of metocean data which include wave, wind, and current data is a prerequisite for the operation and survival of offshore structures. The purpose of this study was to provide information about the return wave, wind, and current values for the Barents Sea using extreme value analysis. Hindcast datasets of the Global Reanalysis of Ocean Waves 2012 (GROW2012) for a waves, winds and currents were obtained from the Oceanweather Inc. The Gumbel distribution, 2 and 3 parameters Weibull distributions and log-normal distribution were used for the extreme value analysis. The least square method was used to estimate the parameters for the extreme value distribution. The return values, including the significant wave height, spectral peak wave period, wind speed and current speed at surface, were calculated and it will be utilized to design offshore structures to be operated in the Barents Sea.

• Asian Journal of Atmospheric Environment
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• 제5권1호
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• pp.29-40
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• 2011

In this study, the effects of an urban thermal environment on air quality were investigated using hourly surface weather observation data and air quality data over six summers from 2000 to 2005 in two cities on the Korean Peninsula. One, the city of Daegu, is representative of basin topography and the other, the city of Busan, represents a coastal area. It is known that the characteristics of an urban thermal environment are represented as an "urban heat island". Here, we focus on the nighttime urban thermal environment, which is called a "tropical night", during the summer. On tropical nights in Busan, the temperature and cloud cover levels were higher than on non-tropical nights. Wind speed did not appear to make a difference even on a tropical night. However, the frequency of southwestern winds from the sea was higher during tropical nights. The prevailing southwest winds in all areas meant an inflow of air from the sea. So at most of the air quality stations, the ozone concentration during tropical nights was lower than during non-tropical nights. In Daegu, the tropical nights had higher temperatures and cloud covers. Despite these higher temperatures, the ozone concentration during the tropical nights was lower than that on non-tropical nights at most of the air quality stations. This feature was caused by low irradiance, which in turn caused an increased cloud cover. Wind speed was stronger during the tropical nights and dispersed the air pollutants. These meteorological characteristics of the tropical nights reduced ozone concentrations in the Daegu Basin.

• 한국환경과학회지
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• 제20권6호
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• pp.737-753
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• 2011

The typical characteristics of seasonal winds were studied around the Pohang using two-stage (average linkage then k-means) clustering technique based on u- and v-component wind at 850 hpa from 2004 to 2006 (obtained the Pohang station) and a high-resolution (0.5 km grid for the finest domain) WRF-UCM model along with an up-to-date detailed land use data during the most predominant pattern in each season. The clustering analysis identified statistically distinct wind patterns (7, 4, 5, and 3 clusters) representing each spring, summer, fall, and winter. During the spring, the prevailed pattern (80 days) showed weak upper northwesterly flow and late sea-breeze. Especially at night, land-breeze developed along the shoreline was converged around Yeongil Bay. The representative pattern (92 days) in summer was weak upper southerly flow and intensified sea-breeze combined with sea surface wind. In addition, convergence zone between the large scale background flow and well-developed land-breeze was transported around inland (industrial and residential areas). The predominant wind distribution (94 days) in fall was similar to that of spring showing weak upper-level flow and distinct sea-land breeze circulation. On the other hand, the wind pattern (117 days) of high frequency in winter showed upper northwesterly and surface westerly flows, which was no change in daily wind direction.

• 한국지구과학회지
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• 제40권5호
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• pp.502-517
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• 2019

지구온난화와 급속한 기후 변화는 북서 태평양 내 태풍의 특성에 오랫동안 영향을 미쳤고, 이로 인해 한반도 연안에서 치명적인 재해가 증가하고 있다. 마이크로파 센서의 일종인 Synthetic Aperature Radar (SAR)는 위성 광학 및 적외선 센서로는 바람을 구할 수 없는, 흐린 대기 조건인 태풍 주위에서 고해상도 바람장을 생산할 수 있다. SAR 자료로부터 해상풍을 산출하기 위한 Geophysical Model Functions (GMFs)에는 풍향 입력이 필수적이며, 이는 태풍 중심을 정확히 추정하는 것에 기반해야 한다. 본 연구는 태풍 중심 탐지 방법의 문제점을 개선하고 이를 해상풍 산출에 반영하기 위하여, Sentinel-1A 영상을 이용해 태풍 중심을 추정하였다. 그 결과는 한국 및 일본 기상청이 제공한 태풍 경로자료와 비교하여 검증하였고, Himawari-8 위성의 적외 영상도 활용하여 검증하였다. 태풍의 초기 중심 위치는 VH 편파를 이용해 설정하여 오차의 발생 가능성을 줄였다. 탐지된 중심은 한국 및 일본 기상청에서 제공하는 4개 태풍의 경로 자료와 평균 23.76 km의 차이를 보였다. Himawari-8 위성에서 추정된 태풍 중심에 비교했을 때 결과는 육지 근처에 위치하면서 58.73 km의 큰 차이를 보인 한 태풍을 제외하고는 평균 11.80 km의 공간 변이를 보였다. 이는 고해상도 SAR 영상이 태풍 중심을 추정하고 태풍 주위 해상풍 산출에 활용될 수 있음을 시사한다.

• Ocean and Polar Research
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• 제32권4호
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• pp.351-359
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• 2010

This study examined extensive patches of floating green macroalgal (Ulva prolifera) mats in the northern East China Sea (ECS) using satellite images from mid May through July 2008 and field observation made during early August 2008 cruise. It was previously reported that the massive macroalgal blooms occurred in the coastal areas of Qingdao in China. During our field survey, researchers noticed widely distributed floating patches of macroalgal mats ranging in size from tens of centimeters to a few hundred meters in diameter. Meteorological data in the northern ECS showed high irradiance, high air-temperature, and predominant southerly winds in summer. In the study area during the survey period, surface waters were characterized by the Changjiang Diluted Water (CDW) mass, which contained high concentrations of nitrate and phosphate. The internal transcribed spacer (ITS) sequence of U. prolifera found in the northern ECS was the same as those of U. prolifera sampled from Qingdao blooms, suggesting a possibility that U. prolifera found in two regions would be derived from the same origin. We suggest that U. prolifera in the nearshore Jiangsu Province drifted into the northern ECS and proliferated under favorable meteorological and oceanographic conditions during the summer of 2008.

• 해양환경안전학회지
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• 제22권5호
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• pp.508-520
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• 2016

본 연구에서는 7년(2009-2015)간 한반도 주변을 통과한 태풍의 이동 경로에 따른 수온의 변동을 분석하였다. 자료는 위성관측 수온영상, 동해 연안의 양양, 강릉, 삼척, 영덕에서 실시간 계류부이에서 관측한 수온과 기상청에서 제공한 바람을 분석하였다. 위성 영상을 이용한 태풍 통과 전후의 근해 수온의 차이는 태풍의 이동 경로에 따른 바람의 방향뿐만 아니라 해면 가열과 해면 상승의 시기와도 관계가 깊게 나타났다. Muifa, Chanhom, Nakri, Tembin과 같은 태풍들의 오른쪽에 위치한 동해 연안의 수온은 남풍계열의 바람에 의한 연안용승으로 표층뿐만 아니라 15m, 25m의 수온까지 하강하는 것을 알았다. 특히, 태풍 Chanhom과 Tembin에 의한 수온의 하강은 각각 $8-11^{\circ}C$와 $16^{\circ}C$ 하강하였다. 한편 그 반대편에 태풍이 위치할 때는 외해쪽에 있는 고온의 해수를 연안쪽으로 이동하여 침강시킴으로서 중층과 저층의 수온이 상승하였다. 또한, 태풍 통과 이후에 동해 연안에서 남풍(북풍)계열의 바람에 의한 하강(상승)된 수온의 혼합은 1-2일 및 4일간 지속되었다.