• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.755-758
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• 2001

Topex/poseidon 위성의 자료를 통하여 남인도양의 암스테르담- 크호제트- 케르겔른 지역에 대한 표층 순환과 해수면 변화의 시ㆍ공간적인 해석을 쉽게 수행 할 수 있었다. 각 지역에서의 시ㆍ공간적인 변화 특성들을 보면, 암스테르담지역은 서쪽으로 전파하는 로쓰비파가 존재한다. 이때 이 파는 동쪽으로 전파하는 남극순환해류의 영향을 받는다. 1993년 늦가을에서 초겨울 동안에 분지의 동부지역에서 해수면이 급격히 떨어졌다. 이곳은 남극순환해류(아규라스순환반류전선과 아열대전선)의 북부에서 발전하는 시계방향(cyclonic)의 와동류가 예외적으로 강하게 북쪽으로 상승했다가 이어서 급격히 남쪽으로 하강했던 것과 관련된다. 쌩뽈지역은 5cm 정도의 해수면 진동과 함께 약 130일 정도의 주기성을 보였다. 서쪽으로 전파하는 신호인 자유 표면의 진동이 실제로 조사되었다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.380.2-381
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• 1998

• Korean Journal of Remote Sensing
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• v.19 no.4
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• pp.271-276
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• 2003

Sea level variability and eddy in the Amsterdam-Crozet-Kerguelen region of the South Indian Ocean were studied during 1 year (October 15, 1992~October 15, 1993) using multi-satellite data (Topex/Poseidon, ERS1) produced by signal treatment. We found that sea level variabilities (>10cm) generally exist along the Antarctic Circumpolar Current in the area of 35$^{\circ}$~46$^{\circ}$S and strong sea level variabilities (20~30cm) were especially occurred from the effects of eddy due to bottom topography in two small area: 49$^{\circ}$~57$^{\circ}$E and 38$^{\circ}$~42$^{\circ}$S, and 58$^{\circ}$~64$^{\circ}$E and 42$^{\circ}$~44$^{\circ}$S.

• Journal of the Korean earth science society
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• v.23 no.4
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• pp.349-356
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• 2002

In an effort to properly assess the validity of spaceborne radar altimeter measurements, we made a direct comparison of two different sea surface heights (SSH) acquired by both Topex/Poseidon (T/P) satellite and in-situ tide-gauges (T/G). This comparative analysis was conducted using the data sets collected from three locations along the eastern coast of Korea which include: Ulleungdo, Pohang, and Sokcho. In the course of the analysis of satellite altimeter, information of SSH was extracted from the T/P MGDR data sets through the application of both atmospheric and geophysical corrections. To compare the T/P data sets in parallel basis, the T/G data sets were averaged using the measured values within the peripheral radius of 55km. When compared among different locations, the compatibility between the two methods was much more significant in an offshore location (Ulleungdo) than the two onshore locations (Pohang, Sokcho). If the low-pass filtered results were compared among the sites, the offshore site exhibited the best correlations between the two methods (correlation coefficient of 0.91) than those of the onshore sites. These large differences in the strength of correlations among different locations are due to the deformation of M2, S2, and K1 tidal components used in the tidal model. In case of the offshore location, the compatibility of the two different methods were improved systematically by the low-pass filtering with an increase of the filtering duration such as up to 200 days.

• Journal of Astronomy and Space Sciences
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• v.26 no.1
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• pp.89-98
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• 2009

In this study, the YLPODS (Yonsei Laser-ranging Precision Orbit Determination System) is developed for POD using SLR (Satellite Laser Ranging) NP (Normal Point) observations. The performance of YLPODS is tested using SLR NP observations of TOPEX/POSEIDON and CHAMP satellite. JPL's POE (Precision Orbit Ephemeris) is assumed to be true orbit, the measurement residual RMS (Root Mean Square) and the orbit accuracy (radial, along-track, cross-track) are investigated. The validation of POD using GPS (Global Positioning System) raw data is achieved by YLPODS performance and highly accurate SLR NP observations. YGPODS (Yonsei GPS-based Precision Orbit Determination System) is used for generating GPS based precise orbits for TOPEX/POSEIDON. The initial orbit for YLPODS is derived from the YGPODS results. To validate the YGPODS results the range residual of the first adjustment of YLPODS is investigated. The YLPODS results using SLR NP observations of TOPEX/POSEIDON and CHAMP satellite show that the range residual is less than 10 cm and the orbit accuracy is about 1 m level. The validation results of the YGPODS orbits using SLR NP observations of the TOPEX/POSEIDON satellite show that the range residual is less than 10 cm. This result predicts that the accuracy of this GPS based orbits is about 1m level and it is compared with JPL's POE. Thus this result presents that the YLPODS can be used for POD validation using SLR NP observations such as STSAT-2 and KOMPSAT-5.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1997.06a
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• pp.233.2-234
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• 1997

• Korean Journal of Remote Sensing
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• v.14 no.2
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• pp.117-128
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• 1998

Topex/Poseidon satellite, launched in Auguest 1992, has provided more 5 years of very good quality data. Efficient improvements, either about instrumental accuracy or about sea level data correction, have been made so that Topex/Poseidon has become presently a wonderful tool for many researchers. The first mission data of 73 cycles, September 1992 - August 1994, was used to our study in order to know characteristics of environmental correction factors in the Amsterdam-Crozet-Kerguelen region of the South Indian Ocean. According to standard procedures as defined under user handbook for sea surface height data processes, then we have chosen cycles 43 as the cycle of reference because this cycle has provided the completed data for measurement points and has presented the exacted position of ground track compared to another cycles. It was computed variations of various factors for correction in ascending ground track 103(Amsterdam-Kerguelen continental plateau) and descending ground track170 (Crozet basin). Here the variations of ionosphere, dry troposphere, humid troposphere, electromagnetic bias, elastic tide and loading tide were generally very smaller as a few of cm, but the variations of oceanic tide(30-35cm) and inverted barometer(15-30cm) were higher than another factors. For the correction of ocean tide, our model(CEFMO: Code d' Elements Finis pour la Maree Oceanique) - This is hydrodynamic model that is very well applicated in all oceanic situations - was used because this model has especially good solution in the coastal and island area as the open sea area. Conclusionally, it should be understood that the variation of ocean free surface is mainly under the influence of tides(>80-90%) in the Amsterdam - Crozet- Kerguelen region of the South Indian Ocean.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.641-644
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• 2003

Sea level variability and eddy in the Amsterdam-Crozet-Kerguelen region of the South Indian Ocean were studied during 1 year(October 15, 1992~October 15, 1993) using multi-satellite data(Topex/Poseidon, ERSl) produced by signal treatement. We found that generally sea level variabilities(>10cm) exist along the Antarctic Circumpolar Current in the area of 35$^{\circ}$~46$^{\circ}$S and especially strong sea level variabilities(20~30cm) were occurred by the effects of eddy due to botton topography in two small area: 49$^{\circ}$-57$^{\circ}$E and 38$^{\circ}$~42$^{\circ}$S, and 58$^{\circ}$ -64$^{\circ}$E and 42$^{\circ}$-44$^{\circ}$S.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.1
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• pp.61-68
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• 1995

This paper is to provide a reference surface geoid for geodetic applications of satellite altimeter data. The paticular satellite alone or the combination with other altimeter data could be used for the recovery of geoid un-dulations and gravity anomalies in the ocean areas. This paper also describes the geoidal undulation in the ocean area of Korean Peninusla using Geosat, ERS-1 and Topex/Poseidon data. The results show that the quasi-stationary sea surface topography (557) is estimated to be less than 10 cm RMS value in the ocean area of Korean Peninsula. This can be considered as an altimeter geoid.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.290-294
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• 2001

Satellite data, with Sea Surface Temperature(SST) by NOAA and Sea Level(SL) by Topex/poseidon, are used to estimate characteristics on the variations and correlations of SST and SL in the East Asian Seas from January 1993 through May 1998. In the oceanic climate, the variations of SL shown the high values in the main current of Kuroshio and the variations of SST shown not the remarkable seasonal variations because of the continuos compensation of warm current by Kuroshio. In the continental climate, SL shown high variations in the estuaries(the Yellow River, the Yangtze River) with the mixing the fresh water in the mouth of estuaries of the saline water in the coasts of continent and SST shown highly the seasonal variations due to the climatic effect of continents. In the steric variations in summer, the eastern sea of Japan, the East China Sea and the western sea of Korea shown the increment of sea level with 10~20cm. But the Bohai bay in China shown relatively the high values of 20~30cm due to the continental climate. Generally the trends of SST and SL increased during all periods. That is say, the slopes of SST and SL presented 0.29$^{\circ}C$/year and 0.84cm/year, respectively. The annual and semi-annual amplitudes shown a remarkable variations in the western sea of Korea and the eastern sea of Japan.