• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.312-316
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• 2002

Satellite radar interferometry data shows a strong coherent signal on oyster sea farms where artificial structures installed on the bottom. We obtained 21 highly coherent interferograms from eleven JERS-1 SAR data sets despite of large orbital baseline (~2 km) or large temporal baseline (~l year). The phases observed in sea farms are probably induced by double bouncing on sea surface, and consequently reveal a tide height variation. To restore the absolute sea level changes we counted the number of wrapping by exploiting the intensity of backscattering. Backscattering intensity is closely correlated with the change in water surface height, while interferometry gives the detailed variation within the limit of 2$\pi$ (or 15.3 cm). Comparing the radar measurements with the tide gauge records yielded a correlation coefficient of 0.96 and an ms error of 6.0 cm. The results demostrate that radar interferometry is promising to measure sea level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.518-524
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• 2008

A three-dimensional primitive equation model (POM) and the buoy data (2900 N, 13500 E) from the Japan Meteorological Agency (JMA) for 27 typhoons between 1982 and 2000 are used to investigate the sea surface cooling (SSC) that accompanies typhoons in the northwestern Pacific. Observed sea surface temperatures (SSTs) rapidly drop 0.6 to 4.3 C, and SSC continues for several weeks after the passage of a typhoon. The model, which covers most of the northwestern Pacific ($24^{\circ}N$ to $52^{\circ}N$), simulated Typhoon Abby over the tropical Pacific, and successfully reproduces many observed features, including the pattern of SST decrease, inertial oscillations, etc. The model accurately simulated the SSC process, suggesting that the cyclonic eddy with a radius of a few hundred kilometers that trailed Typhoon Abby plays an important role in SSC.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.37-42
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• 2003

We have analyzed the characteristics of the sea surface winds and wind waves near the Korean marginal seas on the basis of prediction results of the sea surface winds from MM5/KMA model, which is being used for the operation system at the Korea Meteorological observation buoy data to verify the model results during Typhoon events. The correlation coefficients between the models and observation data reach up to about 95％, supporting that these models satisfactorily simulate the sea surface winds and wave heights even at the coastal regions. Based on these verification results, we have carried out numerical experiments about the wave modulation. When there exist an opposite strong current for the propagation direction of the waves or wind direction, wave height and length gets higher and shorter, and vice versa. It is proved that these modulations of wave parameters are well generated when wind speed is relatively week.

• Ocean and Polar Research
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• v.23 no.2
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• pp.161-172
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• 2001

A model-to-model comparison is attempted between Princeton Ocean Model (POM) and Miami Isopycnic Coordinate Ocean Model (MICOM) as a first step to extend our knowledge of models' performances in studying the East Sea circulation. The two models have fundamentally different numerical schemes and boundary conditions imposed on these models are not exactly the same each other. This study indicates that MICOM has a critical weak point in that it does not reproduce the shallow surface currents properly while it handles the thermohaline processes and associated movements of intermediate and deep waters efficiently. It is suggested that the mixed layer scheme needs to be modified so that it can match with inflow boundary conditions in order to reproduce the surface currents properly in MICOM. POM reproduces the surface current pattern better than MICOM, although the surface currents in POM appear to undergo the unrealistic seasonal variation and have exaggeratedly large vertical scale. These defects seem to arise during the process of adapting POM to the East Sea, and removing these defects is left as a future task.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.441-451
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• 1996

The surface meteorological and upper layer meteorological observation carried out to investigate influences of sea breeze effect on lower layer atmosphere at Gori nuclear power plant for 29∼30 July, 1996. According to surface meteorological data, the inflow of sea breeze was occurred 11:30 on 29 July, 10:30-on 30 July, respectively, at observation site. And the meteorological tower data showed that wind direction of sea breeze was identified as south-westerly, and wind speed of 58 m was 2 times stronger than that of 10 m. It is notworthy that surface inversion layer which built from the night time to daybreak of next day was not broken off by seab reeze's inflow for daytime, and strong inversion layer observed at 47∼243 m with moderately stable class (F) by URC. It was found that strong stable layer of potential temperature appeared at that layer, maximum relative humidity observed at the bottom of inversion layer and maximum mixing ratio observed in the low of inversion layer.

• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.129-135
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• 2016

In this paper, we present a novel algorithm for image-based maritime obstacle detection using global sparsity potentials (GSPs), in which "global" refers to the entire sea area. The horizon line is detected first to segment the sea area as the region of interest (ROI). Considering the geometric relationship between the camera and the sea surface, variable-size image windows are adopted to sample patches in the ROI. Then, each patch is represented by its texture feature, and its average distance to all the other patches is taken as the value of its GSP. Thereafter, patches with a smaller GSP are clustered as the sea surface, and patches with a higher GSP are taken as the obstacle candidates. Finally, the candidates far from the mean feature of the sea surface are selected and aggregated as the obstacles. Experimental results verify that the proposed approach is highly accurate as compared to other methods, such as the traditional feature space reclustering method and a state-of-the-art saliency detection method.

• Proceedings of the KSRS Conference
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• v.2
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• pp.1023-1026
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• 2006

As it was shown recently, climate changes in Antarctica resulted in interannual trends of some climatic parameters like sea level pressure, surface air temperature, ice thickness and others. These tendencies have effect on the Southern Ocean meteorological and hydrological regime. The following remote sensing data: AVHRR MCSST data, satellite altimetry data (merged data of mission ERS-2, TOPEX/Poseidon, Jason-1, ENVISAT, GFO-1) are used to analyse the interannual and/or climatic tendency of sea surface temperature (SST) and sea level anomaly (SLA). According to the obtained results, SST has negative trend $-0.02{\pm}0.003^{\circ}C/yr$ for 24-yr record (1982-2005) and SLA has positive trend $0.01{\pm}0.005$ cm/yr for 24-yr record (1982-2005) and $0.24{\pm}0.026$ cm/yr for 12-yr record (1993-2005). However in some areas (for example, Pacific-Antarctic Ridge) SST and SLA tendencies are stronger $-0.065{\pm}0.007^{\circ}C/yr$ and $-0.21{\pm}0.05$ cm/yr, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.767-777
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• 1999

In the coastal region air flow changes due to the abrupt change of surface temperature between land and sea. So a numerical simulation for atmospheric flow fields must be considered the correct fields of sea surface temperature(SST). In this study, we used variables such as latent heat flux, sensible heat flux, short and long wave radiation of ocean and atmosphere which exchanged across the sea surface between atmosphere and ocean model. We found that this consideration simulated the more precise SST fields by comparing with those of the observated results. Simulated horizontal SST differences in season were 2.5~4$^{\circ}C$. Therefore we simulated the more precise atmospheric flow fields and the movement and dispersion of the pollutants with the Lagrangian particle dispersion model. In the daytime dispersion pattern of the pollutants emitted from ship sources moved toward inland, in the night time moved toward sea by land/sea breeze criculation. But air pollutants dispersion can be affected by inland topography, especially Yangsan and coastal area because of nocturnal wind speed decrease.

• Water for future
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• v.10 no.1
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• pp.101-117
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• 1977

The statatistical characteristics and spectra of sea waves at Mookho were analysed by several statistical methods. As the results, the following conclusions are obtained: 1. Values of surface elevation of sea wave are better fitted to Gram Charlier distribution than Gaussian distribution. This proves that sea waves have not only characters of irregularity but also non-linearity. 2. Distribution of maxima of surface elevation practically follows the distribution of Cartwright and Longuet-Higgins, also spectral width parameter is found to be increased with the increase of root mean square of surface elevation. 3. Sea wave may have spectrum of broad frequency band, however distributions of wave heights and periods follow the Rayleigh distribution which is derived from the assumption of narrow frequency band. 4. Ratios among mean wave heights from observed data show good agreements with theoretical values from Rayleigh distribution. 5. Spectral density and spectral width parameter increase with increase of wind velocity. And wave period at optimum band gas higher value than significant wave period by about 10 percent.

• Ocean and Polar Research
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• v.24 no.3
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• pp.255-261
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• 2002

We investigated the distribution of sea ice using Topex/Poseidon (T/P) and ERS-1 .ada. altimeter data in the northwest Weddell Sea, Antarctica, between the area $45-75^{\circ}W\;and\;55-66^{\circ}S$. Using the Geo_Bad_1 flag of the Merged GDR of the T/P, we classified the surface into ocean, land, and sea. Total 257 cycles of altimeter measurements between Oct. 1992 and Sep. 1999 (for nearly 2570 days) were used to analyze the distribution of the Antarctic sea ice. We then calculated the surface area of ice coverage using SUTM20 map projection to monitor the periodic variations. Each year, the maximum and minimum coverage of the sea ice were found in late August and February in the study area, respectively. We also studied the sea ice distribution using ERS-1 altimeter data between $45-75^{\circ}W\;and\;55-81.5^{\circ}S$ to compare with the T/P Using the Valid/Invalid flag of the Ocean Product, we analyzed the sea ice distribution between March and August of 1995, which showed very good coherence with the T/P measurements. Our preliminary results showed that the altimeter measurements can be effectively used to monitor the distribution of the sea ice in the polar region. However, the size of radar footprint, typically 2-6km depending on the roughness of the sea surface, may be too big to monitor the sharp boundary between ice and water/land. If more other altimeter mission data with dense coverage such as Geosat GM are analyzed together, this limitation can be significantly improved. If we also combine other microwave remote sensing data such as radiometer, and SSM/I, the result will be significantly enhanced.