• Ocean and Polar Research
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• v.38 no.4
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• pp.331-338
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• 2016

Many studies using tracers have been conducted to understand a physical process in a system. Rain-on-snow could accelerate snowmelt processes, which influences the hydrological process in both temperate and polar regions. Hydrological and ecological conditions will be affected by the amount and timing of discharge reaching the bottom of a snowpack. The discharge consists of the rain-on-snow, pore water penetrating into the snowpack and natural meltwater. In this study, after a rain-on-snow experiment, we conducted an isotopic hydrograph separation to distinguish rainwater and pore water from meltwater. Using the isotopic data of snow and meltwater from Lee et al. (2010), two components were separated based on the assumption that rainwater and pore water are new water and natural meltwater is old water. After the second rain-on-snow experiment, the maximum contributions of rainwater and pore water reached up to 69% of the discharge and then decreased. During the study period, the measured total discharge was 4153 L and 40% (based on hydrogen isotope) of rainwater and pore water was calculated in the discharge, which is not consistent with what Lee et al. (2016) calculated using chemical separation (63%). This inconsistency can be explained by how an end-member was defined in both approaches. The contributions of artificial rainonsnow and pore water to melwater discharge range between the two methods. This study will suggest a mixing calculation from isotopic compositions of the Southern Ocean.

• Ocean and Polar Research
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• v.37 no.4
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• pp.327-332
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• 2015

Isotopic compositions of ice and meltwater play a very crucial role in paleoclimate studies based on ice cores and water resources research conducted in alpine hydrogeology. Better understanding of variations in the stable isotopic compositions of water is required since changes from ice to liquid water are gaining more attention due to recent climate change. In this work, a melting experiment was designed and conducted to investigate how the isotopic compositions of ice vary with time by heat sources, such as solar radiation. We conducted the melting experiment for 22 hours. The discharge rate rose to a maximum value after 258 minutes and gradually declined because we fixed the heat source. The isotopic compositions of meltwater increased linearly or to a second degree polynomial. The linear relationship between oxygen and hydrogen has a slope of 6.8, which is less than that of the Global Meteoric Water Line (8) and higher than a theoretical value (6.3). The deuterium excess decreased when ${\delta}D$ or ${\delta}^{18}O$ increases or vise versa since the slope of the relationship for ice-liquid exchange is less than 8. These findings and the apparatus of the melting experiments will make a helpful contribution to the studies of stable isotopes and the melting process in temperate and polar regions.

• Journal of the Korean Geographical Society
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• v.41 no.5 s.116
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• pp.513-526
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• 2006

The timing and extent of glaciations during the Late Quaternary in the South Shetland Islands, West Antarctica were defined using field mapping, geomorphic analysis and radiocarbon dating. Landforms of glacial erosion and deposition, in particular subglacial meltwater channel erosion, suggest that at least three glaciations occurred during the late Quaternary within the study region. During the global LGM, glacial troughs (such as Maxwell Bay and Admiralty Bay) were overdeepened by an ice stream moving south from $an\sim1000m-thick$ ice cap centered on the present-day continental shelf to the north. This ice was responsible for the subglacial meltwater channel erosion, and glacial polished and striated bedrock on the Fildes Peninsula. The recent local glaciations occurred about 2,000 years ago and during Little Ice Age (LIA). During these glaciations, glaciers were less extensive than the previous one and less erosive as a cold-based ice

• Journal of the korean society of oceanography
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• v.33 no.1-2
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• pp.1-7
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• 1998

In the western Weddell Sea, winter mixed layer is characterized by near-freezing temperature and higher salinity due to brine injection through sea-ice formation. This layer becomes Winter Water being capped by warmer and less saline Antarctic Surface Water during the sea-ice melt-ing season. In this study, Winter Water was preliminarily identified by the oxygen isotopic com-positions. The ${\delta}^{18}$O values of Winter Water show the progressively increasing trend from south to north in the study area. It presumably reflects the enhanced mixing with Antarctic Surface Water due to the extent of influence by low S'"0 value of sea-ice/glacier meltwater. Correlations between salinity and 6'"0 values of seawater can be used to more generally characterize Winter Water with a view to identification. However, the prediction on the degree of mixing from these relationships needs more detailed isotope data, although this study allows the oxygen isotopic composition of seawater as a tracer to identify the water mass.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.599-608
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• 2000

One dimensional numerical modeling was carried out for the melting behavior of dry snow and the unsaturated flow when heat was supplied from the bottom surface. Discrepancy between the previous experimental data and the present numerical results is substantially reduced by considering the density change of water permeation layer due to the infiltration of meltwater. In the parametric study for effective thermal conductivity, it was found that the effect of this parameter to the behavior of snow melting is minor. Sensitivity analysis showed that the melting time is most sensitive to changes in supplied heat flux, snow temperature, and bulk density, whereas snow bulk density and residual saturation have a significant effect on the height of water permeation layer in snow.

• Proceedings of the Korean Quaternary Association Conference
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• 2004.06a
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• pp.51-51
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• 2004

As an important contribution to the planed drilling (IODP) in the central part of the Arctic Ocean, we are currently working on a refined chronostratigraphy for Marine Isotope Stage (MIS) 16 to MIS 2 on the exciting material from ODP Site 910A (Leg 151) which has been recovered from the marginal Eastern Arctic Ocean (the Yermak Plateau - the Atlantic/Arctic Ocean Gateway). Several stratigraphic age fix-points support the interpretation of the stable oxygen. isotope record of planktonic foraminifer N, pachyderma sin. that is punctuated by several short-term meltwater events. We believe that our new record will serve as 'the important correlating tool for establishing a basic stratigraphy for the Quaternary Arctic Ocean as well as for generating high-resolution paleoenvironmental reconstructions in the central Arctic Ocean. Furthermore, our study will provide reference stratigraphic data sets for interpreting the micropaleontological, sedimentological and organic / inorganic - geochemical proxies of the new boreholes that will be drilled on the Lomonosov Ridge(Central Arctic Ocean) in the frame of the "Arctic Coring Expedition' (ACEX, IODP) in summer 2004.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.1-7
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• 2003

Environmental changes caused by the abrupt climatic change are one of the important issues in the scientific community. In the East Sea, abrupt climatic shift, called Younger Dryas, is identified. The age of the Younger Dryas cold episode occurred at 11.2 ka. Overall, changes in circulation and bottom water conditions occurred during the Younger Dryas cold episode in the study area. Especially, climatic transition from meltwater spike to the Younger Dryas cold episode is characterized by significant shifts of oxygen isotope values, the coiling ratios of Neogloboquadrina pachyderma, and the planktonic foraminifers abundances. The impact of abrupt climate change on the ecosystem is very significant. In the East Sea, the calcium carbonate secreting organism(foraminifers) is replaced by silicon dioxide secreting organisms(diatom, radiolarian) after the abrupt and severe cold climatic event. Based on the Doctrine of Uniformitarianism, at least climate change for the next 100 years would be severely influence on the marine ecosystem.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.514-519
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• 2009

The purpose of this study is to show the method of applying snow thermal storage system through the analysis of the cases in Japan. The results were as follows. (1) The systems in Japan were installed at the location whose annual mean air temperature was $14.6^{\circ}C$ or below and annual snowfall was 59 cm or above. (2) By analyzing the characteristics of the systems, meltwater circulation system with a backup chiller was confirmed to be most suitable for Korea. (3) For the first time in Korea, the system with the snow storage of 500 ton was designed at Muju after analyzing regional climate characteristics.

• Journal of the korean society of oceanography
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• v.35 no.1
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• pp.34-45
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• 2000

Spatial distributions of phytoplankton biomass and nutrients were examined to investigate the magnitude of phytoplankton blooms along the marginal ice zone (MIZ) in the northwestern Weddell Sea during austral summer of 1995. High phytoplankton biomass was associated with the MIZ in the study area. Vertical stability induced by meltwater appears to be the most important factor controlling phytoplankton biomass distribution. Nitrate concentrations are significantly depleted within the upper water column at the phytoplankton biomass maximum. The time required to attain the observed nutrient depletion was calculated from phytoplankton biomass and nitrate depletion, which ranges from 27 to 68 days in transect 4 and from 33 to 145 days in transect 3. Phytoplankton production was also calculated from nitrate depletion and time-scales of nitrate depletion, which varies from 272 to 1752 mg C m$^{-2}$ day$^{-1}$ in transect 4 and from 327 to 2648 mg C m$^{-2}$ day$^{-1}$ in transect 3. In the Southern Ocean where primary productivity shows large temporal and spatial variations, the productivity measurement from nutrient depletion can provide an average rate of primary production during phytoplankton bloom.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.82-89
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• 2011

Understanding snowmelt movement to the watershed is crucial for both climate change and hydrological studies because the snowmelt is a significant component of groundwater and surface runoff in temperature area. In this work, a new energy balance budget algorithm has been developed for melting snow from a snowpack at the Central Sierra Snow Laboratory (CSSL) in California, US. Using two sets of experiments, artificial rain-on-snow experiments and observations of diel variations, carried out in the winter of 2002 and 2003, we investigate how to calculate the amount of snowmelt from the snowpack using radiation energy and air temperature. To address the effect of air temperature, we calculate the integrated daily solar radiation energy input, and the integrated discharge of snowmelt under the snowpack and the energy required to generate such an amount of meltwater. The difference between the two is the excess (or deficit) energy input and we compare this energy to the average daily temperature. The resulting empirical relationship is used to calculate the instantaneous snowmelt rate in the model used by Lee et al. (2008a; 2010), in addition to the net-short radiation. If for a given 10 minute interval, the energy obtained by the melt calculation is negative, then no melt is generated. The input energy from the sun is considered to be used to increase the temperature of the snowpack. Positive energy is used for melting snow for the 10-minute interval. Using this energy budget algorithm, we optimize the intrinsic permeability of the snowpack for the two sets of experiments using one-dimensional water percolation model, which are $52.5{\times}10^{-10}m^2$ and $75{\times}10^{-10}m^2$ for the artificial rain-on-snow experiments and observations of diel variation, respectively.