• 한국지역지리학회지
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• 제18권1호
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• pp.17-26
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• 2012

한반도 서부의 황토현에 분포하는 적색의 풍화층은 온대몬순기후의 한반도 기후환경과 어울리지 않는 토색을 띤다. 이 적색토(풍화층)는 화학적 풍화를 반영한 것으로서, 화학적 풍화지수(CIA)와 A-CN-K 도식을 활용하면 그 특색을 규명할 수 있다. CaO와 $Na_2O$의 손실은 대부분 이루어진 상태이며, $K_2O$의 손실이 단면 하부에서 상부로 가면서 점차 진행되고 있는 상태이다. 풍화단계에 따른 풍화 진전 방향을 유형화 하면, A-CN-K 도식에서 일반 구릉대 풍화층에서 나타나는 풍화 초 중기 단계에는 A-CN 선을 따라 풍화가 진전되며, 황토현 일대와 같이 강한 화학적 풍화가 진전된 풍화 후기에는 A-K 선을 따라 $K_2O$의 손실이 이루어지면서 풍화가 진전된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.459-463
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• 2005

몬순지역에 속한 우리나라의 대부분 저수지에서는 여름철 집중호우시 탁수가 유입되므로, 저수지 수질관리를 위해 고탁수층의 진행경로, 시공간적 분포, 그리고 방류량조절 등에 의한 탁수저감효과를 예측할 필요성이 있다. 저수지의 성층현상이 임하호의 탁도분포에 미치는 영향을 검토하기 위하여 월별 수온분포가 검토되었고 또한 수리 및 수질모형 CE-QUAL-W2를 이용하여 2차원 수치모의가 수행되었다. 임하호의 6월 수온분포는 표층은 $24^{\circ}C$이고 심층은 $6^{\circ}C$이고 중층은 비교적 선형으로 변화한다. 8월달 수온 분포는 표층의 수온은 $30^{\circ}C$정도이고 심층은 심층은 $6^{\circ}C$이고중층은 $22^{\circ}C$에서 $18^{\circ}C$이고 2개의 수온약층이 존재한다. 6월과 8월의 중층수온분포를 비교해보면 6월은 상대적으로 수온변화가 크고 8월은 수온변화가 작으므로 중층에서의 이송확산이 8월에 보다 활발할 것으로 판단된다. 임하호 성층현상이 탁도분포에 미치는 영향을 파악하기 위하여 6월과 8월의 수온분포의 경우에 대하여 임하호 유역에 80 mm와 120 mm의 총강우량이 발생한 경우에 대하여 수치모의를 수행하였다. 초기 저수위는 El. 148 m와 El. 152 m의 조건을 적용하였다. 수치모의결과는 2002년 태풍루사의 경우에 대하여 검증하였다. 수치모의결과는 다음과 같다. 탁수층 선단이 댐체에 도달하는 시간은 초기 저수위가 높고 중층의 수온분포가 상대적으로 균일한 8월이 긴 것으로 나타났다. 이러한 현상은 유입수가 저수지로 유입되면서 초기수위가 높은 경우에 운동량이 상대적으로 많이 소멸되기 때문으로 판단된다. 또한 탁수층의 두께도 8월 성층의 경우가 상대적으로 큰 것으로 나타났다. 이는 중층의 8월 수온분포 또는 밀도분포가 상대적으로 균일하기 때문에 연직방향 이송$\cdot$확산이 많이 이루어졌기 때문으로 판단된다.

• 대기
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• 제15권2호
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• pp.91-99
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• 2005

This study compares the summer monsoon circulations during a heavy rainfall period over the Korean peninsular from 11 to 18 July 2004, simulated by three widely used regional models; WRF, MM5, and RSM. An identical model setup is carried out for all the experiments, except for the physical option differences in the RSM. The three models with a nominal resolution of about 50 km over Korea are nested by NCEP-DOE reanalysis data. Another RSM experiment with the same cumulus parameterization scheme as in the WRF and MM5 is designed to investigate the importance of the representation of subgrid-scale parameterized convection in reproducing monsoonal circulations in East Asia. All thee models are found to be capable of reproducing the general distribution of monsoonal precipitation, extending northeastward from south China across the Korean peninsula, to northern Japan. The results from the WRF and MM5 are similar in terms of accumulated precipitation, but a slightly better performance in the WRF than in the MM5. The RSM improves the bias for precipitation as compared to those from the WRF and MM5, but the pattern correlation is degraded due to overestimation of precipitation in northern China. In the comparison of simulated synoptic scale features, the RSM is found to reproduce the large-scale features well compared to the results from the MM5 and WRF. On the other hand, the simulated precipitation from the RSM with the convection scheme used in the MM5 and WRF is closer to that from the WRF and MM5 simulations, indicating the significant dependency of simulated precipitation in East Asia on the cumulus parameterization scheme.

• 한국환경과학회지
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• 제23권7호
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• pp.1321-1332
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• 2014

The key objective of this study was to evaluate trophic state and empirical water quality models along with analysis of fish trophic guilds in relation to water chemistry (N, P). Trophic state index (TSI), based on total phosphorus (TP) and chlorophyll-a (CHL), ranged between oligotrophic and hypereutrophic state, by the criteria of Nurnberg(1996), and was lower than the trophic state of total nitrogen (TN). Trophic relations of Secchi depth (SD), TN, TP, and CHL were compared using an empirical models of premonsoon (Pr), monsoon (Mo), and postmonsoon (Po). The model analysis indicated that the variation in water transparency of Secchi depth (SD) was largely accounted (p < 0.001, range of $R^2$ : 0.76-0.80) by TP during the seasons of Mo and Po and that the variation of CHL was accounted (p < 0.001, $R^2=0.70$) up to 70% by TP during the Po season. The eutrophication tendency, based on the $TSI_{TP}$ vs. $TSI_{N:P}$ were predictable ($R^2$ ranged 0.85-0.90, p < 0.001), slope and y intercept indicated low seasonal variability. In the mean time, $TSI_{N:P}$ vs. $TSI_{CHL}$ had a monsoon seasonality in relation to values of $TSI_{N:P}$ during the monsoon season due to a dilution of reservoir waters by strong monsoon rainfall. Trophic compositions of reservoir fish reflected ambient contents of TN, TP, and CHL in the reservoir waters. Thus, the proportions of omnivore fish increased with greater trophic conditions of TP, TN and CHL and the proportions of insectivore fish decreased with greater trophic conditions.

• 대한공간정보학회지
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• 제25권1호
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• pp.3-8
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• 2017

본 연구에서는 앙상블 중규모기후모델 weather research and forecasting(WRF)를 이용하여 2045년부터 2054년까지 21세기 중반의 기후변화에 대한 우리나라 미래 풍력자원 지도를 제작하였고 월별, 시간대별 자원변화를 검토하였다. 분석결과, 한반도상에서 강한 몬순 순환으로 인해 뚜렷한 월별 시공간 변동성이 해륙풍에 의한 시간대별 변동성보다 컸다. 풍력자원이 큰 강풍지역은 월마다 지역마다 다르게 나타났다. 즉 겨울철 북서계절풍(여름철 남서계절풍)이 주풍일 때 각각 강원산간과 해상 그리고 남서해안에서 자원이 많을 것으로 전망되었다. 최대풍과 최소풍은 1월, 9월에 각각 나타날 것으로 전망되었고, 시간대별로 내륙과 산간은 일중편차가 컸지만 연안지역은 편차가 작을 것으로 전망되었다. 이는 현재기후에 대한 기존분석결과와는 다소 차이가 있는 것으로, 이 연구에서 생산된 미래 풍력자원 지도는 향후 기후 변화 가능성이 큰 지역의 시공간적 풍황을 감안하여 풍력단지 입지 선정 및 풍력운영을 위한 장기계획 마련에 있어서 유용한 자료가 되리라 기대된다.

• 대기
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• 제18권1호
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• pp.55-70
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• 2008

The global time slice approach is a transient experiment using high resolution atmosphere-only model with boundary condition from the low resolution globally coupled ocean-atmosphere model. The present study employs this "time slice concept" using ECHAM4 atmosphere-only model at a horizontal resolution of T106 with the lower boundary forcing obtained from a lower-resolution (T42) greenhouse gas + aerosol forcing experiment performed using the ECHO-G/S (ECHAM4/HOPE-G) coupled model. In order to assess the impact of horizontal resolution on simulated East Asian summer monsoon climate, the differences in climate response between the time slice experiments of the present and that of IPCC SRES AR4 participating 21 models including coarser (T30) coupled model are compared. The higher resolution model from time slice experiment in the present climate show successful performance in simulating the northward migration and the location of the maximum rainfall during the rainy season over East Asia, although its rainfall amount was somewhat weak compared to the observation. Based on the present climate simulation, the possible change of East Asian summer monsoon rainfall in the future climate by the IPCC SRES A1B scenario, tends to be increased especially over the eastern part of Japan during July and September. The increase of the precipitation over this region seems to be related with the weakening of northwestern part of North Pacific High and the formation of anticyclonic flow over the south of Yangtze River in the future climate.

• 한국도로학회논문집
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• 제19권5호
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• pp.131-141
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• 2017

PURPOSES : The main distress of asphalt pavements in monsoon climate regions are caused by water damage and plastic deformation due to repeated rain season and increased heavy vehicle traffic volume. In this study, the mechanical properties of polymer-modified warm mix asphalt (PWMA) materials are evaluated to use in monsoon climate regions such as Indonesia. METHODS : Comprehensive laboratory tests are conducted to evaluate moisture resistance and permanent deformation resistance for three different asphalt mixtures such as the Indonesian conventional hot-mix asphalt (HMA) mixture, the polymer-modified asphalt mixture, and the polymer-modified warm mix asphalt (PWMA) mixture. Dynamic immersion test and indirect tensile strength ratio test are performed to evaluate moisture resistance. The wheel tracking test is performed to evaluate rutting resistance. Additionally, the Hamburg wheel tracking test is performed to evaluate rutting and moisture resistances simultaneously. RESULTS :The dynamic immersion test results indicate that the PWMA mixture shows the highest resistance to moisture. The indirect tensile strength ratio test indicates that TSR values of PWMA mixture, Indonesian PMA mixture, and Indonesian HMA mixture show 87.2%, 84.1%, and 67.9%, respectively. The wheel tracking test results indicate that the PWMA mixture is found to be more resistant to plastic deformation than the Indonesian PMA. The dynamic stability values are 2,739 times/mm and 3,150 times/mm, respectively. Moreover, the Hamburg wheel tracking test results indicate that PWMA mixture is more resistant to plastic deformation than Indonesian PMA and HMA mixtures. CONCLUSIONS :Based on limited laboratory test results, it is concluded that rutting resistance and moisture susceptibility of the PWMA mixture is superior to Indonesian HMA and Indonesian PMA mixtures. It is postulated that PWMA mixture would be suitable for climate and traffic conditions in Indonesia.

• 대기
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• 제20권3호
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• pp.379-386
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• 2010

현재 지구온난화로 인하여 산악 및 육상 빙하가 녹고 있으며, 이는 해수의 순환변화를 초래한다. 온난화는 또한 몬순의 변화를 일으켜 집중호우, 홍수, 가뭄등의 빈도수와 지속기간을 증가 시킨다. 특히 온난화로 인한 집중호우의 증가는 해양으로 유기탄소의 유입을 증가시켜 해양은 더욱 더 이산화탄소 농도가 높아지며 해수는 부식성이 강하며 산성화 되어 생물체를 죽이며 궁극적으로 생물 다양성이 감소된다. 현재처럼 이산화탄소를 계속 배출할 경우 미래의 해양은 산성화되어 탄산칼슘으로 구성된 생물체의 각을 녹여 생물체가 죽으며, 이는 먹이사슬의 변화를 초래해 생태계에 부정적인 영향을 미친다. 만약 현재처럼 이산화탄소를 배출할 경우 IPCC 의 예측처럼 2100년까지 $6^{\circ}C$ 상승하며, 이는 열 염분순환을 중지시켜 생물체의 대량 멸종을 초래 할 수 있다(Stokstad, 2002).

• 한국물환경학회지
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• 제29권5호
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• pp.598-609
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• 2013

Spatial and temporal distribution of environmental factors and epilithic diatom communities in major rivers (30 rivers and 58 sampling points) of the Korean peninsula were surveyed each one time before (May) and after the monsoon (October) 2012. The stream of the east harbor (EAST), the south harbor (SOUTH), and the west harbor (WEST) was sampled in order. Over the survey, a total of 284 taxa were classified, and the number of diatom species in each harbor did not show significant changes after the monsoon, but a biomass significantly decreased. Results also showed that EAST deterioration of water quality and chlorophyll-a after the monsoon, was opposite to SOUTH. Five major dominant species including Nitzschia inconspicua, which contained higher biomass over the survey, were common species which widely distributed in brackish water. Indicator Species Analysis showed that a large number of clean water species in EAST and polluted water species in SOUTH and WEST were emerged respectively. In sum, the Asian monsoon significantly decreased a biomass of epilithic diatoms and water qualities over the harbors (lower stream) in the Korean peninsula, but did not change the major species indicating water quality.

• 한국물환경학회지
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• 제22권5호
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• pp.933-942
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• 2006

In this study, temperature, turbidity, suspended paniculate matter (SPM) distribution and mineral characteristics were investigated to explain spatial distribution of the turbid-water environment of Yongdam reservoir in July, 2005. Six stations were selected along a longitudinal axis of the reservoir and sampling was conducted in four depths of each station. Water temperature was showed the typical stratified structure by the effects of irradiance and inflow. Content of inorganic matter in suspended particles increased with the concentration of suspended particulate matter (SPM) due to the reduction of ash-free dry matter (AFDM). Turbidity ranged from 0.6 to 95.1 NTU and the maximum turbidity value of each station sharply increased toward downstream from upstream. The high turbidity layers were located at the depth between 12~16 m. Particle size ranged from 0.435 to $482.9{\mu}m$. day and silt-sized particles corresponded 91.9~98.9% and 1.1~8.0% in total numbers of SPM, respectively. Turbidity showed high correlations with clay (r=0.763, p<0.05) and silt content (r=0.870, p<0.05).Inorganic matter content (r=0.960, p<0.01) was more correlated with turbidity than organic matter (r=0.823, p<0.05). Mineral characterization using x-ray diffraction and electron probe microanalyzer demonstrated that the major minerals contained in the SPM were kaolinite, illite, vermiculite and smectite. As results of this study, surface water discharge as well as small size of the SPM were suggested as long-term interfering factors in settling down the turbid water in the reservoir.