• Journal of Wetlands Research
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• v.13 no.3
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• pp.471-479
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• 2011

Evapotranspiration (ET) including evaporation from a land surface and transpiration from photosynthesis of vegetation is a hydrological factor that has an important role in water cycle. However, there is a limitation to understand it due to heterogeneity of land cover and vegetation. In this study, Mapping EvapoTRanspiration with Internalized Calibration (METRIC) model, one of the energy balance models, and MODerate resolution Imaging Spectroradiometer (MODIS) satellite based well-known Penman-Monteith algorithm were compared. Two ET maps were categorized and compared by land cover classification. The results represented overall applicability of the two models with the highest correlation coefficients in needleleaf and broadleaf forests. This study will be useful to estimate remote sensing based ET maps with high resolution and to figure out spatio-temporal variability and seasonal changes.

• Journal of the Korean earth science society
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• v.27 no.7
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• pp.804-815
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• 2006

Meteorologists define a drought as a period of common dry weather. This may sound straightforward, but it is not so in reality. In this study, we attempted to identify meteorological drought conditions over South Korea. To evaluate the temporal and spatial variability of drought, we calculated two commonly used drought indices, the percent of normal precipitation (PNP) and the Palmer drought severity index (PDSI) calculated from fifty-eight meteorological stations below the Korean Meteorological Administration (KMA). The yearly precipitation has been growing gradually, and the amplitude between maximum and minimum also grow more explicitly from 1960's. According to the analysis of percentile anomaly of monthly precipitation, major drought duration was $1927{\sim}1929,\;1937{\sim}1939,\;1942{\sim}1944,\;1967{\sim}1968,\;1976{\sim}1977,\;1982{\sim}1983,\;1988,\;and\;1994{\sim}1995$. The severe drought occurred most frequently in Mokpo, Daegu, Jeonju, Busan, and Gangneung; it tended to occur more frequently in south sector than in mid sector of Korea and in south west sector than in south east sector. According to the analysis of seasonal distribution, extreme droughts occurred frequently in winter at Seoul, Gangneung, Jeonju, Daegu, and Busan. Severe droughts in summer were formed frequently at Seoul, Gangneung, and Mokpo, while that for spring at Jeonju, Daegu, and Busan. The results of PDSI distribution for the $1994{\sim}1995$ drought period were one of the most severe and widely spreaded droughts; it occurred most frequently in the south sector of South Korea. The comparison of time series between PDSI and Normal Percent showed that they exhibit a strong compatibility for the entire study period; it implies that both drought indices are useful method to indicate drought severity.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.711-721
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• 2004

The aim of this study is to clarify whether frequency and/or severity of extreme climate events have changed significantly in Korea during recent years. Using the best available daily data, spatial and temporal aspects of ten climate change indicators are investigated on an annual and seasonal basis for the periods of 1954-1999. A systematic increase in the $90^{th}$ percentile of daily minimum temperatures at most of the analyzed areas has been observed. This increase is accompanied by a similar reduction in the number of frost days and a significant lengthening of the thermal growing season. Although the intra-annual extreme temperature range is based on only two observations, it provides a very robust and significant measure of declining extreme temperature variability. The five precipitation-related indicators show no distinct changing patterns for spatial and temporal distribution except for the regional series of maximum consecutive dry days. Interestingly, the regional series of consecutive dry days have increased significantly while the daily rainfall intensity index and the fraction of annual total precipitation due to events exceeding the $95^{th}$ percentile for 1901-1990 normals have insignificantly increased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.385-392
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• 2016

Seasonal variability in the algal community structure of intertidal zones was examined at six study sites in Marine National Parks, on the western and southern coasts of Korea from March to November 2015. A total of 193 species of algae, comprising 27 green, 40 brown and 126 red algae, were identified. Algal biomass averaged 101.50 g dry wt./m² with a maximal at Tonggae (168.12 g dry wt./m²) and minimum at Haseom (54.49 g dry wt./m²). The dominant seaweeds by biomass were Sargassum thunbergii at five sites (Tonggae, Haseom, Namdongri, Ando amd Sinjeonri), and S. fusiforme at Soando. Community indices measured as follows: dominance index (DI), 0.31–0.69; richness index (R), 7.30–11.43; evenness index (J'), 0.33–0.49; and diversity index (H'), 1.15–1.86. As evaluated using community indices and environmental states, the EEI (Ecological Evaluation Index) of the Marine National Park was “normal”. The present results indicate that seaweed community structures and indices could be used to evaluate the environmental status of coastal ecosystems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.55-64
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• 2017

Seasonal variability in algal community structure was examined at the intertidal zones of five study sites on the Taean Peninsula, on the western coast of Korea, from February 2014 to November 2015. A total of 118 species of marine algae, comprising 17 green, 24 brown and 77 red algae, were identified. The maximum number of species was observed at the Mohang site (75 species), and the minimum at the Yeonpo site (46 species). The seaweed biomass was $160.24g\;dry\;wt./m^2$ on average, and was maximal at Uihang ($519.04g\;dry\;wt./m^2$) and minimal at Yeonpo ($19.03g\;dry\;wt./m^2$). Based on biomass, the dominant seaweeds at Taean peninsula were Sargassum thunbergii and Corallina pilulifera. Community indices were as follows: richness index (R), 3.21-5.01; evenness index (J'), 0.33-0.38; and diversity index (H'), 0.90-1.12. Based on evaluation of the environmental states by the community indices, the ecological evaluation index (EEI) of Taean peninsula was "moderate". The overall species and biomass of seaweeds decreased after the oil spill. However, Hakampo previously showed a similar algal community structure. In conclusion, the algal community was temporarily affected by the oil spill, but rapidly recovered.

• Ocean and Polar Research
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• v.31 no.1
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• pp.11-29
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• 2009

Variability of sea surface temperature (SST) in the Japan/East Sea (JES) was studied using complex empirical orthogonal function (CEOF) analysis. Two daily data sets were analyzed: (1) New Generation 0.05o-gridded SST from Tohoku University, Japan (July 2002-July 2006), and (2) 0.25o-gridded SST from the Japan Meteorological Agency (October 1993-November 2006). Linkages with wind stress curl were revealed using 6-h 1o-gridded surface zonal and meridional winds from ancillary data of the Sea- WiFS Project, a special National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) product (1998-2005). SST anomalies (SSTA) were obtained by removing the seasonal signal, estimated as the leading mode of the CEOF decomposition of the original SST. Leading CEOF modes of residual SSTA obtained from both data sets were consistent with each other and were characterized by annual, semiannual, and quasi-biennial time scales estimated with 95% statistical significance. The Semiannual Mode lagged 2 months behind the increased occurrence of the anticyclonic (AC) wind stress curl over the JES. Links to dynamic processes were investigated by numerical simulations using an oceanic model. The suggested dynamic forcings of SSTA are the inflow of subtropical water into the JES through the Korea Strait, divergence in the surface layer induced by Ekman suction, meridional shifts of the Subarctic Front in the western JES, AC eddy formation, and wind-driven strengthening/weakening of large-scale currents. Events of west-east SSTA movement were identified in July-September. The SSTA moved from the northeastern JES towards the continental coast along the path of the westward branch of the Tsushima Current at a speed consistent with the advective scale.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E1
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• pp.1-9
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• 2007

In Korea, there is only a limited amount of information currently available on the levels of airborne bacteria and fungi of cattle sheds, although certain portions of people are potentially exposed to these bioaerosols in cattle sheds. Accordingly, the current study measured them inside cattle sheds, inside and outside farmers' houses near the sheds, and/or inside residential houses far away from the sheds during winter, 2004 and summer, 2005. The airborne bacteria and fungi were detected in most samples in the cattle farmers' houses as well as in the cattle sheds. Aspergillus, Cladosporium, and Penicillium, which have been associated with adverse health effects, were three most prevalent fungal genera, and they took most of the total fungi (more than 69%). The microbial concentrations measured inside the cattle sheds were comparable to those in other reports. Nevertheless, the present arithmetic and geometric mean (GM) microbial concentrations exceeded the Korean guideline for total airborne bacteria at medical facilities ($800\;CFU\;m^{-3}$), the current GM residential indoor concentrations at houses, and the residential indoor levels reported in other countries. The present findings suggest the need for a strategy to reduce Korean cattle farmers' exposure to these microorganisms. In contrast to the microbes, it is suggested that the cattle shed is not an important microenvironment for $PM_{10}$ exposure. Two characteristics examined in this study (seasonal variation and summer survey period, i.e., temperature and humidity) were all important for the cattle farmers' occupational exposure to airborne microbes. The lack of constancy between highest and lowest concentrations of bioaerosols over the survey period further suggests the necessity of performing a long-term survey to better examine farmer exposure levels and their variability.

• Atmosphere
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• v.18 no.4
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• pp.507-524
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• 2008

In this paper, future climate changes over East Asia($20^{\circ}{\sim}50^{\circ}N$, $100^{\circ}{\sim}150^{\circ}E$) are projected by anthropogenic forcing of greenhouse gases and aerosols using coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) B1, A1B and A2 scenarios. Before projection future climate, model performance is assessed by the $20^{th}$ Century (20C3M) experiment with bias, root Mean Square Error (RMSE), ratio of standard deviation, Taylor diagram analysis. The result of examination of the seasonal uncertainty of T2m and PCP shows that cold bias, lowered than that of observation, of T2m and wet bias, larger than that of observation, of PCP are found over East Asia. The largest wet bias is found in winter and the largest cold bias is found in summer. The RMSE of temperature in the annual mean increases and this trend happens in winter, too. That is, higher resolution model shows generally better performances in simulation T2m and PCP. Based on IPCC SRES scenarios, East Asia will experience warmer and wetter climate in the coming $21^{st}$ century. It is predict the T2m increase in East Asia is larger than global mean temperature. As the latitude goes high, the warming over the continents of East Asia showed much more increase than that over the ocean. An enhanced land-sea contrast is proposed as a possible mechanism of the intensified Asian summer monsoon. But, the inter-model variability in PCP changes is large.

• Ocean and Polar Research
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• v.23 no.2
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• pp.141-160
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• 2001

The challenge of predicting the Japanese coastal ocean motivated Frontier Observational Research System for Global Change (FORSGC) and the Japan Marine Science and Technology Center (JAMSTEC) to start a multiyear observational programme in the upstream Kuroshio in November 2000. This field effort, the Kuroshio Observation Program (KOP), should enable us to determine the barotropic and baroclinic components of the western boundary current system, thus, to better understand interactions of the currents with mesoscale eddies, the Kuroshio instabilities, and path bimodality. We, then, will be able to improve modeling predictability of the mesoscale, seasonal, and inter-annual processes in the midstream Kuroshio near the Japanese main islands by using this knowledge. The KOP is focused on an enhanced regional coverage of the sea surface height variability and the baroclinic structure of the mainstream Kuroshio in the East China Sea, the Ryukyu Current east of the Ryukyu's, and the Kuroshio recirculation. An attractive approach of the KOP is a development of a new data acquisition system via acoustic telemetry of the observational data. The monitoring system will provide observations for assimilation into extensive numerical models of the ocean circulation, targeting the real-time monitoring of the Japanese coastal waters.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.19-35
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• 2003

In order 새 investigate the spatial and seasonal variations of heavy metal pollution in heavily industrialized urban area, urban roadside sediments were collected for five years from gully pots in Seoul City. A series of studies have been carried out concerning the physicochemical characteristics of the sediments in order to evaluate the contamination of heavy metals such as Cd, Co, Cr, Cu, Ni, Pb and Zn. Roadside sediments and uncontaminated stream sediments were analyzed for total metal concentrations using acid extraction. The roadside sediments are characterized by very high concentrations of Zn (2,665.0$\pm$1,815.0 $\mu\textrm{g}$/g), Cu (445.6$\pm$708.0 $\mu\textrm{g}$/g), Pb (214.3$\pm$147.9 $\mu\textrm{g}$/g) and Cr (182.1$\pm$268.8 $\mu\textrm{g}$/g), indicating an artificial accumulation of these metals to the sediment chemistry. Comparing with average contents of uncontaminated stream sediments, roadside sediments were shown zinc 14 times (up to 64.4), copper 9 times (up to 181.7), lead 6 times (up to 63.7), cobalt 6 times (up to 168.7), nickel 4 times (up to 98.4), cadmium 2 times (up to 12.8) and chrome 2 times (up to 40.2) high content. The relative degree of heavy metal pollution for roadside sediments collected from each district in Seoul City is evaluated using the “geoaccumulation index”. As a result, heavy-metal contamination is highest centering the oldest residential district and industry area, and contamination level decreases as go to outer block of the city. The factor analysis results indicate that the levels of Cu, Ni, Fe and Cr are strongly related to numbers of factories, whereas the concentrations of Cr, Zn and Cd dependant on pollution index, indicating artificial contamination due to site-specific traffic density.