• Atmosphere
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• v.20 no.2
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• pp.63-71
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• 2010

In this study, we derived the wind speed at 50 m and 80 m above sea level from 567 stations over a period of 1 year and correlated to measured wind speed at 5 radiosonde sites. From these correlations, we derived and analyzed the spatial distribution of wind map over Korea based on hourly observational data recorded over a period of 5 years from 2004 to 2008. As a results, wind speed is generally high over seashores, mountains, and islands. Mean wind speed over Korea at 50 and 80 m above sea level for 5 years during 2004 to 2008 seasonally are highest at Spring, and then followed by Winter, Fall, and Summer. In 76 (14%) stations, mean wind speed at 80 m above sea level for 5 years during 2004 to 2008 are greater than $5ms^{-1}$. The prevailing winds over Korea at 80 m above sea level for 5 years during 2004 to 2008 are North (44%), Northwest (16%), and West (15%). In 99 stations, the % of wind faster than $5ms^{-1}$ was higher than 40%, and in 62 stations, the % of wind faster than $5ms^{-1}$ was higher than 50%. In 178 station, the % of prevailing winds was higher than 30%, and there are 7 stations which also have wind speeds over $5ms^{-1}$, ranking from highest to lowest, Dongsong, Daegwallyeong, Baekun Mt., Hyangrobong Mt., Sorak Mt., Gosan, and Misiryeong Mt..

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.3 s.26
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• pp.185-192
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• 2006

Distribution of wind direction and wind speed is very important from the viewpoint of ship's safety because it is closely related to the formation and development of sea wave. In this study, the climatological characteristics of monthly wind distribution in a greater coasting area of Korea are analyzed by the ECMWF objective analysis data for the period from 1985 to 1995{11 years). Distributions of wind direction from October to March are very similar and wind speed is strongest in January. The NW'ly and WNW'ly winds at a latitude of 30 degrees N and northward and the NE'ly wind in the Straits of Taiwan and the South China Sea are sustaining and very strong. Distributions of wind direction from June to August are similar and the SW'ly and SSW'ly winds in the South China Sea are strong. The strong Southeast trades exists in the winter hemisphere{Southern Hemisphere). Wind speeds in April, May and September are generally weak.

• Journal of the Korean earth science society
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• v.31 no.5
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• pp.475-487
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• 2010

Sea surface wind field was retrieved from high-resolution SIR-C SAR data by using CMOD algorithms off the east coast of Korea. In order to extract wind direction information from SAR data, a two-dimensional spectral analysis method was applied to the normalized radar cross section of the image. An $180^{\circ}$-ambiguity problem in the determination of wind direction was solved by selecting a direction nearest to the wind vector of the ECMWF reanalysis data. Comparison of the wind retrieval patterns with the ECMWF and NCEP/NCAR dataset showed RMS errors in the range of 1.30 to $1.72\;ms^{-1}$. In contrast, comparison of wind directions revealed large errors of greater than $60^{\circ}$, which is enormously higher than the permitted limit of about $20^{\circ}$ for satellite scatterometer winds. Compared with wind speed results from different algorithms, wind vectors based on commonly-used CMOD4 algorithm showed good agreement with those derived by other algorithms such as CMOD_IFR2 and CMOD5, particularly at medium winds from 4 to $8\;ms^{-1}$. However, apparent discrepancy appeared at low winds (< $4\;ms^{-1}$). This study also addressed an importance of accurate wind direction data to improve the accuracy of wind speed retrieval and discussed potential causes of wind retrieval errors from SAR data.

• Journal of Environmental Science International
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• v.21 no.2
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• pp.153-163
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• 2012

The seasonal variations of ozone ($O_3$) concentrations were investigated with regard to the relationship between $O_3$ and wind distributions at two different sites (Jung Ang (JA): a semi-closed topography and Seo Chang (SC): a closed topography) within a valley city (Yangsan) and their comparison between these sites (JA and SC) and two non-valley sites (Dae Jeo (DJ) and Sang Nam (SN)) located downwind from coastal cities (Busan and Ulsan). This analysis was performed using the data sets of hourly $O_3$ concentrations, meteorological factors (especially, wind speed and direction), and those on high $O_3$ days exceeding the 8-h standard (60 ppb) during 2008-2009. In summer and fall (especially in June and October), the monthly mean values of the daily maximum $O_3$ concentrations and the number of high $O_3$ days at JA (and SC) were relatively higher than those at DJ (and SN). The increase in daytime $O_3$ concentrations at JA in June was likely to be primarily impacted by the transport of $O_3$ and its precursors from the coastal emission sources in Busan along the dominant southwesterly winds (about 5 m/s) under the penetration of sea breeze condition, compared to other months and sites. Such a phenomenon at SC in October was likely to be mainly caused by the accumulation of $O_3$ and its precursors due to the relatively weak winds under the localized stagnant weather condition rather than the contribution of regional transport from the emission sources in Busan and Ulsan.

• Journal of Environmental Science International
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• v.5 no.2
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• pp.131-140
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• 1996

Analysis of hourly variations of sulfur dioxide ($SO_2$) concentrations affected by regional climates for the period of yellow sandy dusts was carried out from March 31 through April 9, 1993. The concentration of 50, at a coastal city, Kangnung city, was much higher than that at an inland city Wonju in the west, but the hourly distrbutions of $SO_2$ concentrations show a similar tendency at both cities. Under the prevailing synoptic-scale westerly winds blowing over a high Mt. Taegualyang in the west toward Kangnung city in the eastern coastal region, the $SO_2$ at Kangnung is trapped by an easterly sea-breeze during the day and under prevailing easterly winds, it is also isolated by the high wall of Mt. Taegualyang, with its high concentration from 14 to 16 LST. Furthermore, when the westerly winds were dominent all day long the high $SO_2$ concentrations at Kangnung were produced by its intrusion from a urban city, Wonju or China in the west into a mountainous coastal city, Kangnung, to some extent, and when the air becomes rapidly cooled down at the clear daytime or the nighttime, their concentrations are also increased by a great amount of heating fuel combustion. Especilly, its maximum concentrations were shown in Wonju and Kangnung from 08 LST through 10 LST, due to the increase of auto vehicles near the beginning time of office hour and were detected again after sunset due to both increases of vehicles at the end of office hour and heating fuel combustion. During the period of Yellow Sandy Dusts which are transported from China into Korea, the $SO_2$ concentrations on rainy days at Wonju and Kangnung were much lower than the monthly mean values of $SO_2$, and their low concentrations could be caused by the scavenging process of rain.

• Atmosphere
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• v.16 no.4
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• pp.279-301
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• 2006

This study analyzed the characteristics of the wind waves near the Korean marginal seas in the 2002 - 2005 year using the third generation wave model, WAVEWATCH - III model. In order to investigate the model performance, model results were compared with the marine meteorological observation results. The 4 years average correlation coefficient between model and observation shows very high value of about 0.77. The model of this study represents very well the characteristics of wind waves near the Korean marginal seas. Simulated monthly sea surface winds and wind waves show the evident spatial variations and this model also simulates very well seasonal characteristics of wind waves in this region.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.246-260
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• 2014

A 90-m horizontal-resolution numerical model was configured to study the micrometeorological features of local winds in the valley of Gwangneung KoFlux (Korea Flux network) Sites (GDK: Gwangneung Deciduous forest site in Korea, GCK: Gwangneung Coniferous forest site in Korea) during summer days. The U. S. Geological Survey (USGS) Shuttle Radar Topography Mission (SRTM) data were employed for high-resolution model terrain height. Model performance was evaluated by comparing observed and simulated near-surface temperature and winds. Detailed qualitative analysis of the model-simulated wind field was carried out for two selected cases which are a clear day (Case I) and a cloudy day (Case II). Observed winds exhibited that GDK and GCK, as well as Case I and Case II, had differences in timing, duration and strength of daytime and nighttime wind direction and speeds. The model simulation results strongly supported the existence of the drainage flow in the valley of the KoFlux tower sites. Overall, the simulated model fields realistically presented the diurnal cycle of local winds in and around the valley, including the morning drainage-upslope transition and the evening reversal of upslope wind. Also, they indicated the complexity of local winds interactions by presenting that daytime westerly winds in the valley were not always pure mountain winds and were often coupled with larger-scale wind systems, such as synoptic-scale winds or mesoscale sea breezes blowing from the west coast of the peninsula.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.1-15
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• 2004

Sea/land circulation system is a representative mesoscale local circulation system in coastal area. In this study, wind fields around coastal area. Pohang, which is affected by this system was investigated and its detailed characteristic analysis was carried out. The following can be found out from the numerical simulation. Generally, at nighttime mountain winds prevail and land breeze toward the coastal area was well simulated During daytime, valley wind and sea breeze was simulated in detail. Especially, as a result of analyzing the land breeze path, it could be found along the coastline as it flows out through low land coastal area. In order to investigate the accuracy of model results. wind speed, temperature and wind direction of continuous typical sea/land breeze occurrence day was compared with observation data. Analyzing the characteristics of local circulation system was very hard because of horizontally sparse observation data but from the above result, a numerical simulation using RAMS, which satisfies the spatial high resolution, will provide more accurate results.

• Journal of the Korean Institute of Navigation
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• v.14 no.2
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• pp.33-59
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• 1990

In cold season, the developed extratropical cyclones and associated cold fronts, and NW winter monsoon are encountered very frequently in the North Pacific, especially in the northwest part of it. The two sea areas, namely, the northwest part of North Pacific, especially the eastern area far off Japan east coast, and Burmuda Triangle in the North Atlantic are generally known as two of the most dangerous areas in the world because of high incidence of sea casualties. Even large ocean going vessels were sunk frequently due to strong winds and very high seas caused by NW monsoon or developed cyclones during the winter months. The purpose of this paper is to analyse the real state of heavy weather and high sea phenomena on the vesscls at sea, thus helping mariners operate in such conditions.

• Journal of the Korean Institute of Navigation
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• v.11 no.1
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• pp.107-144
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• 1987

In cold season, ice accretion on ship, drift ice, NW winter monsoon, developed extratropical cyclones and associated cold fronts, in warm season, tropical cyclones and dense sea fogs, are encountered very frequently in the North Pacific, especially in the northwest part of it. The two areas, namely, the northwest part of the North Pacific and Burmuda Triangle in the North Atlantic are generally known as most dangerous areas in the world because its high incidence of sea cascualities. In recent years, the small fisherboats operating in the northern seas were frequently sunk in a group as they encountered ice accretion or drift ice. And ocean going vessels were also sunk frequently due to strong winds and very high seas in winter monsoon or developed cyclones and cold fronts. The purpose of this paper is to analyze the real state of heavy weather conditions such as ice accretion on ship drift, ice, typhoons and sea fogs, and also to analyse the effect of these heavy weather phenomena on the vessels at sea, thus helping mariners operate in such heavy weather conditions.