• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.3
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• pp.127-134
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• 2010

This study investigated the accuracy of mean sea level pressure(MSLP) predicted by weather models around Korean Peninsula during typhoon Manyi and Usagi period in 2007. The mesoscale regional model, RDAPS, KWRF with 30 and 10 km horizontal resolution and developed high-resolution WRF models with 9 and 3 km horizontal resolutions are used to predict the features of MSLP. The predicted MSLP aspects were verified using observed results from total 35 coastal stations including AWS and ocean buoy. Although 4 models showed the reasonable MLSP results during typhoon periods, the highest resolution, 3km WRF model show the most accurate MSLP results with maximum 69% and 60% improvement with comparisons of RDAPS and KWRF, respectively.

• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.403-407
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• 2008

Relations between variation of SSTs(sea surface temperatures) in the South Sea of Korea and intensity of typhoons which passed through the South Sea of Korea was analyzed for 36 years from 1970 to 2005. The SSTs in the South Sea show the rising trends continuously. The mean SST of the last 10 years(1996-2005) is higher $1.03^{\circ}C$ than the mean SST during 10 years(1970-1979). The rising trends are especially strong after 1994. The intensity of typhoon can be shown by the minimum sea level pressure. The minimum sea level pressures of typhoons which passed through the South Sea show the descending trends. The mean minimum sea level pressure of the last 10 years(1996-2005) is lower 10.1hPa than that during 10 years(1970-1979). The correlation analysis shows that the rising of SSTs in the South Sea has relations with the strengthening of intensity of typhoons.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.535-544
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• 2009

Signals from the Global Positioning System(GPS) satellite are used to retrieve the integrated amount of water vapor or the precipitable water vapor(PWV) along the path between a transmitting satellite and ground-based receiver. In order to retrieve the PWV from GPS signal delay in the troposphere, the actual zenith wet delay, which can be derived by extracting the zenith total delay and subtracting the actual zenith hydrostatic delay computed using surface pressure observing, will be needed. Since it has been not co-located between GPS permanent station and automated weather station, the air-pressure on the mean sea level has been used to determine the actual zenith hydrostatic delay. The directly use of this air-pressure has been caused the dilution of precision on GPS PWV retrieval. In this study, Korean reverse sea level correction method of air-pressure was suggested for the improving of GPS PWV retrieval capability and the accuracy of water vapor estimated by GPS was evaluated through a comparison with radiosonde PWV.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.167-183
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• 2013

This paper aimed to investigate the Asian dust source region and climatic condition of source region by the case of Asian dust in south Korea. In order to analyze the weather condition of source region, observed the Asian dust days data and weather data in China were used. The Asian dust days originating from inner-Mongolia were the most frequent. The Asian dust days originating from all the source regions except Loess plateau were increased recently and occurred over the country. In case of Loess plateau, the frequency of the Asian dust days in 1960s was the highest and only the southern region of the south Korea was mostly affected. The relationship between the Asian dust days of Korea and climatic factors of spring and April of source region was significant. The relationship between the Asian dust days originating from the inner Mongolia and sea level pressure of April and relative humidity of spring was negative. The Asian dust days from Gobi had positive relationship with wind gust days and negative relationship with sea level pressure in April. The Asian dust days from Manchuria had negative relationship with precipitation and sea level pressure in April. The Asian dust days from Loess plateau had positive relationship with maximum wind speed and negative relationship with sea level pressure in April.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.3
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• pp.217-227
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• 2012

On 31 March 2007, the abnormal wave occurred along western coast of Korean including Yeonggwang. In this paper, this event is studied using available field measurement data for the event analysis and numerical model for reproducing the unknown waves. We found several 1-min interval tidal elevation and mean sea level pressure (MSLP) data along the western coast of Korea and analyzed it using wavelet technique. We computed the arrival time and the propagation direction of abnormal wave using wavelet results and performed the numerical simulation using 2 dimensional shallow water wave model. The sea level under the forcing of air pressure jump was obviously amplified by the Proudman resonant effect. The computed sea levels compared with observations are underestimated, but the order of arrival time at the tidal station showed good agreement.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.29-36
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• 2016

Accuracy of GPS (global positioning system) deteriorates dramatically or positioning is impossible in urban area occasionally since high-rise buildings and elevated roads make the reception of navigation signal very difficult so that number of visible satellites decreases. In these cases, vertical error usually becomes much larger than the horizontal error due to the intrinsic geometry of GPS satellites. To obtain more accurate and reliable height information, this paper proposes a hybrid method that combines GPS and a low-cost barometric altimeter. In the proposed method, the sea-level pressure and the sea-surface temperature are applied to the output of the altimeter. Next, the difference between the ellipsoid and the geoid is compensated. Finally, a simple Kalman filter combines the compensated barometric altitude and the GPS height. By static and car experiments, performance of the proposed method is evaluated. By the experiment results, it can be seen that the proposed method improves the altitude accuracy considerably.

• Journal of the Korean association of regional geographers
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• v.11 no.4
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• pp.429-439
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• 2005

The propose of this study is to identify distributional characteristics of winter droughts through occurrence frequencies and to analyze synoptic characteristics on the sea level pressure fields and 500hPa levels in Korea. The regional distributions of winter droughts in occurrence frequency vary according to the monthly regional distributions of the variabilities of precipitation in Korea. In January and December, the eastern parts of Korea where the variabilities of precipitation show high, have high rate of drought frequencies, while the western parts have low rate of it. It means that the regional distribution of the drought frequencies in January and December shows the east-high and west-low pattern, In February the frequencies show the north-high and south-low pattern. In the distributions of the sea-level pressure and 500hPa level height anomalies, the positive anomalies appear around Korean Peninsula and Siberian high area, the negative anomalies on the Aleutian low area and the western parts of North Pacific Ocean during the drought period in January and February. The droughts appear when the inflow of warm and humid air from the south eastern parts blocked by the prevailing pressure patterns of the west-high and east-low. Therefore, the zonal wind of the Korean Peninsula is strong. The droughts of December reflect not only low frequencies of cyclone occurrence, also small inflow of warm and humid air from the southern parts stemming from positive anomalies over whole middle latitude of eastern parts of Asia including Korean Peninsula.

• 한국해양학회지
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• v.25 no.4
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• pp.161-181
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• 1990

A numerical model is established in order to simulate the storm surges which were observed in the seas around Korea during typhoon and winter storm periods. The typhoons are Brenda (1985), Vera (1986) and Thelma (1987). the winter storm period is January 1-6, 1986. The simulated surges for the typhoon periods show good agreements with the recorded ones for the periods at the Korean coasts, but those for the winter storm show fair agreements in general tendencies, not in details. The model simulation in open sea shows a positive sea level near the typhoon center and a native sea level behind the typhoon. the positive surge seems to be due to the low pressure near a typhoon center and the negative on due to the wind stresses of the typhoon. The negative sea level is usually in the form of an elongated gyre. In the gyre, there is a cyclonic circulation of sea water, in which the pressure gradient force induced by the circular depression of the sea surface is balanced by the Coriolis force in readjusting stage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.188-202
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• 1997

The seasonal variability of the sea surface winds over the last Sea of Korea (Japan Sea) is investigated by means of empirical orthogonal function (EOF) analysis. The combined representation of fields of three climatic variables by empirical orthogonal functions is discussed. The eigenvectors are derived from daily sea level pressure, wind speed and 10-day mean sea surface temperature (SST) during 15 years $(1978\~1992)$. The spatial patterns of the mean pressure are characterized by the high pressure in the western part and the low pressure in the eastern part. The spatial distribution of the standard deviation (SD) of pressure are characterized by max SD of 6.6 mb near the Vladivostok, and minima along the coast of the Japan. In Vladivostok, the maxima of SD of SST and south-north wind (WV) were also occurred. The representation of fields of individual meteorological variables by EOF shows that the first mode of the west-east wind (WU) explain over $47.3\%$ of the variance and the second mode of WU represents $30\%$. Especially, the first mode of the WV explain $70.9\%$ of the variance and their time series coefficients show 1-cpy, 0.5-cpy frequency spectrum. The spatial distribution of the first mode eigenvectors of SST are characterized by maximum near Vladivostok. The combined representation of fields of several variables (pressure, wind, SST) reveals that the first mode magnitudes of the variance of the combined eigenvectors (WU-PR) are increased. By means of this result, the 1-year peak and the 6-months peak are remarkable. In the three combined patterns (wind, pressure, SST), the second mode of the eigenvector (wind) is affected by the SST. Their time coefficients of the first mode show noticeable 1-year peak. The spectral analysis of the second mode shows broad seasonal signal with the period of 4-months and a significant peak of variability at 3-month period.

• Journal of the Korean Geographical Society
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• v.52 no.1
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• pp.1-13
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• 2017

This study aims to identify the warm and cold periods(WP, CP) of November appeared in the daily normals of daily minimum temperature of Seoul for 1941~1970 and 1971~2000 and to investigate synoptic characteristics of the temperature changes of WP and CP. The WP temperatures are increased clearly(p value 0.000), the CP temperatures are also warming but not significant statistically. In WP, there are not apparent trends corresponding the warming of WP temperature, in the Siberian High, Sea Level Pressure(SLP), 925hPa surface wind(U925, V925) around the Korean peninsula. In high period(1972~1979) of WP temperature, there are positive SLP anomaly and anomalous anticyclonic circulation pattern of 925hPa wind field over the Korean peninsula then the winter monsoon is weakened and the WP temperature is ascending. In CP, the Siberian high are weakening, the Hokkaido eastern low are strengthening and the westerlies(U925) over the Korean Peninsula are enlarging. So CP temperature are suppressed in rising trend or shows weak descent.