• Ocean and Polar Research
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• v.34 no.1
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• pp.73-83
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• 2012

Antarctica is very sensitive to climate change but the number of stations is not sufficient to accurately analyze climate change in this regoin. Model reanalysis data supplements the lack of observation and can be used as long term data to verify climate change. In this study, the 20CR (Twentieth Century Reanalysis) Project data from NCEP/NCAR and monthly mean data (temperature, solar radiation and longwave radiation) from 1871 to 2008, was used to analyze the temperature trend and change in radiation. The 20CR data was used to validate the observation data from Antarctica since 1950 and the correlation coefficients between these data were determined to be over 0.95 at all stations. The temperature increased by approximately $0.23^{\circ}C$/decade during the study period and over $0.20^{\circ}C$/decade over all of the months. This increasing trend was observed throughout the Antarctica and a slight increase was observed in the Antarctic Peninsula. In addition, solar radiation (surface) and longwave radiation (surface and top of atmosphere) trends correlated with the increase in temperature. As a result, outgoing longwave radiation at the surface is attenuated by atmospheric water vapor or clouds and radiation at the top of the atmosphere was reduced. In addition, the absorbed energy in the atmosphere increases the temperature of the atmosphere and surface, and then the heated surface emits more longwave radiation. Eventually these processes are repeated in a positive feedback loop, which results in a continuous rise in temperature.

• Journal of Mechanical Science and Technology
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• v.19 no.5
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• pp.1216-1225
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• 2005

$CO_{2}$ ocean sequestration is one of the promising options to reduce $CO_{2}$ concentration in the atmosphere because the ocean has vast capacity for $CO_{2}$ absorption. Therefore, in the present investigation, calculations for solubility and dissolution behavior of liquid $CO_{2}$ droplets released at 1000 m and 1500 m deep in the ocean from a moving ship and a fixed pipeline have been carried out in order to estimate the $CO_{2}$ dissolution characteristics in the ocean. The results show liquid $CO_{2}$ becomes bubble at around 500 m in depth, and the solubility of seawater is about $5{\%}$ less than of pure water. Also, it is shown that the injection of liquid from a moving ship is a more effective method for dissolution than from a fixed pipeline, and the presence of hydrate on liquid $CO_{2}$ acts as a resistant layer in dissolving liquid $CO_{2}$.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.287-297
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• 2007

Increasing carbon dioxide emissions from fossil fuel use and land-use change has been perturbing the balanced global carbon cycle and changing the carbon distribution among the atmosphere, the terrestrial biosphere, the soil, and the ocean. SGCM(Simple Global Carbon Model) was used to simulate global carbon cycle for the IPCC emissions scenarios, which was six future carbon dioxide emissions from fossil fuel use and land-use change set by IPCC(Intergovernmental Panel on Climate Change). Atmospheric $CO_2$ concentrations for four scenarios were simulated to continuously increase to $600{\sim}1050ppm$ by the year 2100, while those for the other two scenarios to stabilize at $400{\sim}600ppm$. The characteristics of these two $CO_2$-stabilized scenarios are to suppress emissions below $12{\sim}13$ Gt C/yr by tile year 2050 and then to decrease emissions up to 5 Gt C/yr by the year 2100, which is lower than the current emissions of $6.3{\pm}0.4$ Gt C/yr. The amount of carbon in the atmosphere was simulated to continuously increase for four scenarios, while to increase by the year $2050{\sim}2070$ and then decrease by the year 2100 for the other two scenarios which were $CO_2$-stabilized scenarios. Even though the six emission scenarios showed different simulation results, overall patterns were such similar that the amount of carbon was in the terrestrial biosphere to decrease first several decades and then increase, while in the soil and the ocean to continuously increase. The ratio of carbon partitioning to tile atmosphere for the accumulated total emissions was higher for tile emission scenario having higher atmospheric $CO_2$, however that was decreasing as time elapsed. The terrestrial biosphere and the soil showed reverse pattern to the atmosphere.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.69-74
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• 2013

In this study, the crack healing effects of $Al_2O_3$ ceramics based on the heat treatment conditions were investigated. The influence of the additive amounts of SiC nanoparticles and the cycling process of indentation-heat treatment on the crack healing effect of $Al_2O_3$ ceramics were also examined. Three-point bending tests were carried out and the morphological changes in the fracture surface were observed by using FE-SEM. As a result, heat-treated samples in a vacuum or air atmosphere showed improved bending strengths compared to un-heat treated samples. This means that cracked specimens can be healed by heat treatment in a vacuum or air atmosphere. The crack healing effect of $Al_2O_3$ ceramics that were heat treated in an air atmosphere was much higher than that of those heat treated in a vacuum. After heat treatment, the $Al_2O_3$ ceramics with 30 wt% SiC nanoparticles showed a higher bending strength than those with 15 wt% SiC. The cyclic indentation and heat treatment did not remarkably affect the crack healing effect. The SEM images showed that the median crack, indenter mark on the surface, and pores in the fracture surface of a specimen almost disappeared after being heat treated in an air atmosphere.

• Atmosphere
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• v.15 no.1
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• pp.69-74
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• 2005

In this short article, oceanic processes that could have strong effect on the climate have been explained while focusing on the oceanic thermohaline circulation (THC). First, the structure of THC is explained using a simple scaling law. Then, the thermohaline catastrophe, which is believed to be a cause of a rapid climate changes observed in paleoclimate records, and interdecadal variations in THC are explained. The interactions between the oceans and $CO_2$ are also mentioned briefly.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1541-1551
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• 2023

Radiometric calibration is a fundamental step in ocean color remote sensing since the step to derive solar radiance spectrum in visible to near-infrared wavelengths from the sensor-observed electromagnetic signals. Generally, satellite sensor suffers from degradation over the mission period, which results in biases/uncertainties in radiometric calibration and the final ocean products such as water-leaving radiance, chlorophyll-a concentration, and colored dissolved organic matter. Therefore, the importance of radiometric calibration for the continuity of ocean color satellites has been emphasized internationally. This study introduces an approach to improve the radiometric calibration algorithm for the visible bands of the Geostationary Ocean Color Imager-II (GOCI-II) satellite with a focus on stability. Solar Diffuser (SD) measurements were employed as an on-orbit radiometric calibration reference, to obtain the continuous monitoring of absolute gain values. Time series analysis of GOCI-II absolute gains revealed seasonal variations depending on the azimuth angle, as well as long-term trends by possible sensor degradation effects. To resolve the complexities in gain variability, an azimuth angle correction model was developed to eliminate seasonal periodicity, and a sensor degradation correction model was applied to estimate nonlinear trends in the absolute gain parameters. The results demonstrate the effects of the azimuth angle correction and sensor degradation correction model on the spectrum of Top of Atmosphere (TOA) radiance, confirming the capability for improving the long-term stability of GOCI-II data.

• Journal of Fisheries and Marine Sciences Education
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• v.16 no.2
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• pp.227-237
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• 2004

Recently development trends in information technology expand the activity boundaries for human living beyond coastal zones. These rapid changes of paradigm are stimulating scientists and strategists to be encouraged in making adequate model for marine geographic information system (MGIS) and their applications. Coastal zones are places which are affected by many factors, such as water quality, tide, wave, atmosphere, population, industry, etc. Therefore information related to the coast has to be integrated and analyzed for managing it efficiently. GIS-based Ocean Informatics is suited for those purposes and used in the study for establishing and managing coastal geographic and environmental information system. This paper reviews the properties of ocean and coastal spaces, then defines some MGIS related terminologies for clarifying the scope of MGIS boundaries. In this study, coastal geographic information is established by digital geographic information and digital terrain information. Digital coast chart having information on digital chart and map can merge and analyze various coastal information and can be a useful tool for the coastal integrated management.

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.14-19
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• 2000

A coupled general circulation model (GCM) of the global atmosphere, oceans and lands is used for finding the future climate at times of doubled carbon dioxide concentration (DCDC) of the atmosphere. Two runs of the model were made in order to find the future change. Global changes at times of DCDC may be characterized by a global warmig of $1.4^{\circ}C$, a $3\%$ global precipitation increase, and an increase in the surface available water (SAW) over the global land among others. The estimated increase in SAW over the land implies that river discharge is likely to increase with increased chance of severe weather as a result of the future global warming.

• Proceedings of the KSRS Conference
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• v.2
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• pp.680-683
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• 2006

A one-dimensional planar model is considered of the atmosphere with multi-layer clouds illuminated by a mono-directional parallel flux of solar radiation. A new approach is proposed to radiation transfer modeling and daylight background formation for the atmosphere with such clouds that is represented as a heterogeneous multi-layer system each layer of which is described by different optical characteristics. The influence functions of each layer are determined by solutions of the radiation transfer boundary problem with an external monodirectional wide flux while the contribution of multiple scattering and absorption in the layer is taking into account.

• Atmosphere
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• v.25 no.3
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• pp.569-573
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• 2015

An algorithm to symmetric radius of $15ms^{-1}$ isotaches of tropical cyclones is suggested using infrared (IR) imagery of geostationary satellite. It is assumed that symmetric tangential winds outside the maximum winds exponentially decrease with the radial distances of the tropical cyclone, which has a clear eye-wall structure. Four parameters for estimation of the tropical cyclone size are center location, maximum sustained wind, radius of the maximum wind, and relaxation coefficient for the decreasing rate with distances of the tropical cyclone. The estimation results are limitedly verified as comparing to surface winds of polar orbiting satellite such as ASCAT data.