• Title/Summary/Keyword: Sea Surface Wind

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MERITS OF COMBINATION OF ACTIVE AND PASSIVE MICROWAVE SENSORS FOR DEVELOPING ALGORITHMS OF SST AND SURFACE WIND SPEED

  • Shibata, Akira;Murakami, Hiroshi
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.138-141
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    • 2006
  • In developing algorithms to retrieve the sea surface temperature (SST) and sea surface wind speed from the Advanced Microwave Scanning Radiometer (AMSR) aboard the AQUA and the Advanced Earth Observation Satellite-II (ADEOS-II), data from the SeaWinds aboard ADEOS-II were helpful. Since features of the ocean microwave emission (Tb) related with ocean wind are not well understood, in case of using only AMSR data, combination of AMSR and SeaWinds revealed pronounced features about the ocean Tb. Two results from combinations of the two sensors were shown in this paper. One result was obtained at wind speeds over about 6m/s, in which the ocean Tb varies with the air-sea temperature difference, even though the SeaWinds wind speed is fixed at the same values. The ocean Tb increases as the air-sea temperature difference becomes negative, i.e., the boundary condition becomes unstable. This result indicates that the air temperature should be included in AMSR SST algorithm. The second result was obtained from comparison of two wind speeds between AMSR and SeaWinds. There is a small difference of two wind speeds, which might be related with several mechanisms, such as evaporation and plankton.

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Improvement in the Simulation of Sea Surface Wind over the Complex Coastal Area Using WRF Model (WRF 모형을 통한 복잡 연안지역에서의 해상풍 모의 개선)

  • Kim, Yoo-Keun;Jeong, Ju-Hee;Bae, Joo-Hyun;Oh, In-Bo;Kweon, Ji-Hye;Seo, Jang-Won
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.3
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    • pp.309-323
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    • 2006
  • We focus on the improvement in the simulation of sea surface wind over complex coastal area located in the southeastern Korea. In this study, it was carried out sensitivity experiment based on PBL schemes and dynamic frame of MM5 and WRF. Two widely used PBL parameterization schemes were chosen : Medium-Range Forecast (MRF) and Mellor-Yamada-Janjic (MYJ). Thereafter, two cases of sea fog days with weak wind speed and typhoon days with strong wind speed were simulated and analyzed. The result of experiments indicated that wind fold of WRF model was shown more similar distribution with observational data, compared with that of MM5. Simulation of sea surface wind during sea fog days with weak wind speed and typhoon days with strong wind speed were shown similar horizontal distribution with observational data using MYJ and MRF PBL schemes of WRF model, respectively. Horizontal distribution of sea surface wind was more sensitive according to dynamic frame and PBL Schemes of model during sea fog days and typhoon days, respectively.

On the Characteristic of Wind over Pusan Coastal Area, Korea (부산 연안역의 바람 특성에 관한 고찰)

  • Jeon, Byung-Il;Kim, Yoo-Keun;Lee, Hwa-Un
    • Journal of Environmental Science International
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    • v.3 no.1
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    • pp.1-9
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    • 1994
  • We have Studied the characteristics of wind over Pusan coastal area in order to precisely predict surface wind having an important effect on oil spill fate using the data on surface observation of Pusan, Kimhae and Gadeogdo island which are collected during the 3 years from 1988 to 1990. We also investigated the correlation of the surface wind between Pusan, Kimhae and Gadeogdo island. In both Pusan areas and Kimhae, the land and sea breeze occurs during. the whole season except for winter. The occurrence frequency of land and sea breeze is significantly high from April to August. The correlation of surface wind between Pusan, Kimhae and Gadeogdo island surface wind is high in the daytime. The occurrence frequency of sea breeze in the Kimhae areas is higher than that in Pusan on the basis of the present criteria. For monthly occurrence, Pusan has the highest occurrence frequency of the sea breeze in August and Kimhae has in May.

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The Estimaion of Wind Energy Resources through out the QuikSCAT Data (위성 관측 자료를 이용한 서해 해상 풍력자원 평가)

  • Jang, Jea-Kyung;Yu, Byoung-Min;Ryu, Ki-Wahn;Lee, Jun-Shin
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.486-490
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    • 2009
  • In order to investigate the offshore wind resources, the "QuikSCAT Level 3" data by the QuikSCAT satellite was analyzed from Jan 2000 to Dec 2008. QuikSCAT satellite is a specialized device for a microwave scatterometer that measures near-surface wind speed and direction under all weather and cloud conditions. Wind speed measured at 10 m above from the sea surface as extrapolated to the hub height by using the power law model. It has been found that the high wind energy prevailing in the south sea and the east sea of the Korean peninsula. From the limitation of seawater depth for piling the tower and archipelagic environment around the south sea, the west and the south-west sea are favorable to construct the large scale wind farm. Wind map and monthly variation of wind speed are investigate at the positions.

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Lagrangian observation and modelling of sea surface wind-induced drift(skin drift) (해양 표면취송류(skin drift)의 라그랑쥐 측류 및 모델링)

  • Lee Moonjin;Kang Yong Q.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.3 no.2
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    • pp.11-17
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    • 2000
  • The drift and movement of oil slick in the sea are closely related to the flows at the sea surface (at 0m depth) because specific gravity of an oil is lighter than that of sea water. As an effort toward a development of realistic model for oil spill drift on the sea surface, a study on sea surface wind-induced drift (skin drift) at 4 coastal regions of Korea was carried out. In this study, skin drifts were inferred from difference between the flow at the sea surface and that in underwater (at 1.5m depth). The average speed of skin drift in our experiments was 2.9% of wind speeds and the average direction of skin drift to wind was deflected to the right by 18.6°. The results of this experiment were used in the modelling of the skin drift as a prompt response of time-variable wind. The modelled skin drift, which corresponds to observed wind, successfully reproduced the observed trajectories of sea surface flows.

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Recycling of Suspended Particulates by Atmospheric Boundary Depth and Coastal Circulation (대기경계층과 연안순환에 의한 부유입자의 재순환)

  • Choe, Hyo
    • Journal of Environmental Science International
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    • v.13 no.8
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    • pp.721-731
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    • 2004
  • The dispersion of suspended particulates in the coastal complex terrain of mountain-inland basin (city)-sea, considering their recycling was investigated using three-dimensional non-hydrostatic numerical model and lagrangian particle model (or random walk model). Convective boundary layer under synoptic scale westerly wind is developed with a thickness of about I km over the ground in the west of the mountain, while a thickness of thermal internal boundary layer (TIBL) is only confined to less than 200m along the eastern slope of the mountain, below an easterly sea breeze circulation. At the mid of the eastern slop of the mountain, westerly wind confronts easterly sea breeze, which goes to the height of 1700 m above sea level and is finally eastward return flow toward the sea. At this time, particulates floated from the ground surface of the city to the top of TIBL go along the eastern slope of the mountain in the passage of sea breeze, being away the TIBL and reach near the top of the mountain. Then those particulates disperse eastward below the height of sea-breeze circulation and widely spread out over the coastal sea. Total suspended particulate concentration near the ground surface of the city is very low. On the other hand, nighttime radiative cooling produces a shallow nocturnal surface inversion layer (NSIL) of 200 m thickness over the inland surface, but relatively thin thickness less than 100m is found near the mountain surface. As synoptic scale westerly wind should be intensified under the association of mountain wind along the eastern slope of mountain to inland plain and further combine with land-breeze from inland plain toward sea, resulting in strong wind as internal gravity waves with a hydraulic jump motion bounding up to about 1km upper level in the atmosphere in the west of the city and becoming a eastward return flow. Simultaneously, wind near the eastern coastal side of the city was moderate. Since the downward strong wind penetrated into the city, the particulate matters floated near the top of the mountain in the day also moved down along the eastern slope of the mountain, reaching the. downtown and merging in the ground surface inside the NSIL with a maximum ground level concentration of total suspended particulates (TSP) at 0300 LST. Some of them were bounded up from the ground surface to the 1km upper level and the others were forward to the coastal sea surface, showing their dispersions from the coastal NSIL toward the propagation area of internal gravity waves. On the next day at 0600 LST and 0900 LST, the dispersed particulates into the coastal sea could return to the coastal inland area under the influence of sea breeze and the recycled particulates combine with emitted ones from the ground surface, resulting in relatively high TSP concentration. Later, they float again up to the thermal internal boundary layer, following sea breeze circulation.

Comparison of KMA Operational Model RDAPS with QuikSCAT Sea Surface Wind Data (기상청 현업 모델 RDAPS와 QuikSCAT 해상풍 자료의 비교)

  • You, Sung-Hyup;Cho, Jae-Gab;Seo, Jang-Won
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.5
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    • pp.467-475
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    • 2007
  • This study compared the sea surface wind pattern between model results from KMA operational model (RDAPS) and observational results from QuikSCAT in the 2005-2006 year. The mean spatial distributions of sea surface wind show the prominent seasonal patterns of summer and winter season adjacent to Korean Peninsular. The statistical analysis also shows well seasonal variation of sea surface wind patterns between model and observation results. The BIAS value represents less than -0.5 m/s and -1 m/s in summer and winter seasons, respectively. The spatially averaged correlation coefficient shows larger than 0.7 and 0.8 in summer and winter seasons, respectively. The correlation coefficient of winter season shows higher value than that of summer season in the comparison between model and observation. This results show that the RDAPS model simulate well strong sea surface wind in winter season rather than weak sea surface wind in summer season.

Sea Surface Cold Water near the Southeastern Coast of Korea: Wind Effect (한국(韓國) 남동해안(南東海岸)부근의 해표면(海表面) 냉수(冷水) : 바람의 영향(影響))

  • Byun, Sang-Kyung
    • 한국해양학회지
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    • v.24 no.3
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    • pp.121-131
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    • 1989
  • Cold water observed at sea surface near the southeastern coast of Korea in summers 1982 and 1983 was studied by using data of hydrography, sea level, wind and satellite image. In summer season when water column shows 3-layered structure a "full" upwelling occurs by southwesterly transient wind continuing for several days. During upwelling event, surface water of high temperature moved offshore, middle water of low temperature outcropped to the sea surface, and sea level was lowered, however, equilibrium depth of surface layer was not changed. It may be concluded that cold water at the surface originates from middle layer and strong surface front is a result of surfacing of seasonal thermocline. In order to see the relationship between position of surface front and wind input, a model of Csanady (1982) was applied in a rigid lid approximation. The results show that frontal position can be determined by wind input and water structure near the southeastern coast of Korea. Cold water in summer can appear at the sea surface only when there is wind larger than a minimum wind impulse of order $10m^2/sec$.

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Analysis of Abnormal Sea Surface Temperature in the Coastal Waters of the Yellow Sea Using Satellite Data for the Winter Season of 2004 (인공위성자료를 이용한 2004년 겨울철 황해 연안 해역 이상 수온 해석)

  • Moon, Jeong-Eon;Yang, Chan-Su
    • Korean Journal of Remote Sensing
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    • v.25 no.1
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    • pp.1-10
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    • 2009
  • We studied on the relationship between oceanic variation in the offshore and abnormal sea surface temperature rise in the coastal area of the Yellow Sea using a variety of satellite and in-situ data during winter 2004. In results of the satellite data, the average value of sea surface temperature in the Yellow Sea for 2003 was $10^{\circ}C$, and the average value of sea surface temperature for 2004 was $13^{\circ}C$. It was higher than those of the last year about $3^{\circ}C$. In results of the in-situ data, the average value of surface layer temperature in the Yellow Sea for 2003 was $9.85^{\circ}C$, and the average value of surface layer temperature for 2004 was $12.17^{\circ}C$. In the same satellite data, it was higher than those of the last year about $3^{\circ}C$. In results of the T-S diagram, we divided definitely into water mass of the Yellow Sea and the East China Sea in 2003. But we didn't divide definitely into water mass of the Yellow Sea and the East China Sea in 2004. The average values of air temperature and wind speed for 2003 were $5.23^{\circ}C$ and 4.81 m/s, respectively. And, the average values of air temperature and wind speed for 2004 were $5.61^{\circ}C$ and 4.52 m/s, respectively. So, These were similar. But the wind directions for 2003 were superior northwestern wind, and the wind directions for 2004 were various northern wind. The wind directions were different from each other. Therefore, the abnormal sea surface temperature rise in the coastal area of the Yellow Sea during winter 2004 were better related to oceanic variation in the offshore than influences of atmosphere. In the future, We will do in-depth study for these.

Improvements in the Simulation of Sea Surface Wind Over the Complex Coastal Area-II: Data Assimilation Using LAPS (복잡 해안지역 해상풍 모의의 정확도 개선-II: LAPS를 사용한 자료동화)

  • Bae, Joo-Hyun;Kim, Yoo-Keun;Jeong, Ju-Hee;Kweon, Ji-Hye;Seo, Jang-Won;Kim, Yong-Sang
    • Journal of Environmental Science International
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    • v.15 no.8
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    • pp.745-757
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    • 2006
  • We focus on the improvement of accuracy of sea surface wind over complex coastal area doling the warm season. Local Analysis Prediction System (LAPS) was used to improve the initial values in Mesoscale Meteorological model (MM5). During the clear summer days with weak wind speed, sea surface wind simulated with LAPS was compared with the case without LAPS. The results of modeling with LAPS has a good agreement mesoscale circulation such as mountain and valley winds on land and in case of modeling without LAPS, wind speed overestimated over the sea in the daytime. And the results of simulation with LAPS indicated similar wind speed values to observational data over the sea under influence of data assimilation using BUOY, QuikSCAT, and AMEBAS. The present study suggests that MM5 modelling with LAPS showed more improved results than that of without LAPS to simulate sea surface wind over the complex coastal area.