• Journal of Wetlands Research
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• v.18 no.4
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• pp.432-447
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• 2016

The increased frequency of drought and flood due to climate change was a global problem. In particular, drought was recognized as a serious environmental, ecological, social, and economic disaster. Therefore, it is necessary to study the measures to prevent it. In this study, we will estimate the meteorological drought index in the Han River Basin and analyze the impact of climate change on drought. The change of the meteorological drought occurrence due to climate change in the Han River separated by the common drought and severe drought was analyzed using the Representative Concentration Pathways (RCPs) scenarios provided by the Intergovernmental Panel on Climate Change (IPCC). The years 1973 - 2010 were selected for analysis in the current period. Using the scenario, we separated the future period (Target I: 2011 - 2039, Target II: 2040 - 2069, Target III : 2070 - 2099). The number of occurrences of less than -1.0 and -1.5 standard precipitation index were analyzed by SPI 3, 6, 12. Looking at the results, trends in rainfall in the Han River was expected to increase from the current figures, the occurrence of drought is predicted to decline in the future. However, the number of drought occurrence was analyzed to increase toward long-term drought. The number of severe drought occurrences was usually larger than the common drought estimated. Additional studies may be considered in addition to the agricultural drought, hydrological drought, socio-economic drought. This will be done by using efficient water management. The results can be used as a basis for future drought analysis of the Han River.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.149-156
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• 2019

Assessing the hydrological safety of existing dams against climate change and providing appropriate adaptation measures are important in terms of sustainable water supply and management. Korean major dams ensure their safety through periodic inspections and maintenance according to 'Special Act on the safety control and maintenance of establishments'. Especially when performing a full safety examination, principal engineer must assess the hydrological safety and prepare for potential risks. This study employed future probable maximum precipitation (PMP) estimated using outputs of regional climate models based on RCP4.5 and RCP8.5 greenhouse-gas emission scenarios to assess climate change impact on existing dam's future hydrological safety. The analysis period was selected from 2011 to 2040, from 2041 to 2070, and from 2071 to 2100. Evaluating the potential risk based on the future probable maximum flood (PMF) for four major dams (A, B, C, I) showed that climate change could induce increasing the overflow risk on three dams (A, B, I), although there are small differences depending on the RCP scenarios and the analysis periods. Our results suggested that dam managers should consider both non-structural measures and structural measures to adapt to the expected climate change.

• Journal of the Korean earth science society
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• v.31 no.4
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• pp.313-321
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• 2010

The landform of the study area is defined as a small-scale alluvial plain in the valley bottom adjacent to the coast. By the aggradation of alluvial materials, this valley bottom plain was formed in dissected parts of low hills. For the purpose of reconstructing the palaeo climate environment in this study, $\delta^{13}C$ analysis and soil organic carbon analysis are therefore employed. Main results of this study are as follows: Section I: the period of $6,600{\pm}60yr$ B.P.$-5,350{\pm}60yr$B.P. was mostly in warm and humid climate environment. A little changes of the humid environment are detected as subdry (or sub-humid)${\rightarrow}$humid in terms of the dryness and wetness. Section II: the period of $5,350{\pm}60yr$ B.P.-2,200 yr B.P. was in warm and humid climate environment, which is similar to the present. However, The sediments between $4,720{\pm}60yr$ B.P. and $4,210{\pm}50 yr$ B.P. experienced the most humid climate environment of all studied sedimentary layers. After $4,210{\pm}50 yr$ B.P., the environment started to change from the humid to the sub-humid (or sub-dry) climate. Section III: the period of 2,200 yr B.P.$-210{\pm}60 yr$ B.P. was distinguish from previous two sections as the environmental changes to sub-humid (or sub-dry) climate was apparent.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.4
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• pp.131-142
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• 2017

This study aims to create a Local Climate Zone(LCZ) map of Seoul by using World Urban Database and Access Portal Tools(WUDAPT) protocol, and to analyze the characteristics of the Seoul LCZs. For this purpose, training samples of 17 LCZ types were collected by using Landsat images and Google Earth. LCZ Classification and Filtering were performed by SAGA GIS. An ArcGIS was used to analyze the characteristics of each LCZ type. The characteristics of the LCZ types were analyzed by focusing on building surface fraction ratio, impervious surface fraction ratio, pervious surface fraction ratio, building stories and air temperature. The results show that one filtering was found to be most appropriate. While Yangcheongu and Yeongdeungpogu with the higher annual and maximum mean air temperature than other areas have the higher rate of LCZ 3(compact low-rise) and LCZ 4(open high-rise), Jongnogu, Eunpyeonggu, Nowongu and Gwanakgu with the lower value have the higher rate of LCZ A(Dence trees). The values of building surface fraction ratio, impervious surface fraction ratio and building stories of each LCZ were included in the range of WUDAPT for most LCZs. However, the values of pervious surface fraction ratio were out of the range, in particular, in the LCZs 4~6 and 9~10. This study shows the usability and applicability of the WUDAPT methodology and its climate zone classification used in many countries as a basic data for the landscape planning and policy to improve the thermal environment in urban areas.

• Journal of Korea Water Resources Association
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• v.46 no.11
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• pp.1089-1101
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• 2013

The study uses a regional climate model to check future changes in extreme climate, to calculate extreme indexes presented by STARDEX, and to analyze the trends to predict the continuity and changes in the spatial distribution of extreme climate in the future. An analysis of extreme climate indices showed that they are likely to increase in the Seoul metropolitan area, in Gyeonggi-do, in Yongdong in Gangwon-do, and in the southern shore region of Korea. It is, however, forecasted to diminish in the central inland region. The analysis also showed that the average temperature in Korea will increase because of climate change. On the other hand, an analysis of extreme rainfall indexes showed that the trend of heavy rainfall threshold is 0.229 in Seogwipo, the greatest five-day rainfall is 5.692 in Seogwipo, and the longest dry period is 0.099 in Sokcho. Of extreme temperature indexes, the trend of Hotdays threshold is 0.777 in Incheon and the longest heat wave is 0.162 in Uljin. The Coldnight threshold is 0.075 in Inje and -0.193 in Tongyeong, according to the analysis.

• Journal of the Korean Geographical Society
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• v.51 no.5
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• pp.633-649
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• 2016

Exposure to high temperatures during the reproductive period of crops decreases their productivity. The Intergovernmental Panel on Climate Change's (IPCC) fifth Assessment Report predicts that the frequency of high temperatures will continue to increase in the future, resulting in significant impacts on the world's food supply. This study evaluate climate change-induced heat stress on four major agricultural crops (rice, maize, soybean, and wheat) at a global level, using the coupled atmosphere-ocean model of Hadley Centre Global Environmental Model version 2 (HadGEM2-AO) and FAO/IIASA Global Agro-Ecological Zone (GAEZ) model data. The maximum temperature rise ($1.8-3.5^{\circ}C$) during the thermal-sensitive period (TSP) from the baseline (1961-1990) to the future (2070-2090) is expected to be larger under a Representative Concentration Pathway (RCP) 8.5 climate scenario than under a RCP2.6 climate scenario, with substantial heat stress-related damage to productivity. In particular, heat stress is expected to cause severe damage to crop production regions located between 30 and $50^{\circ}N$ in the Northern Hemisphere. According to the RCP8.5 scenario, approximately 20% of the total cultivation area for all crops will experience unprecedented, extreme heat stress in the future. Adverse effects on the productivity of rice and soybean are expected to be particularly severe in North America. In Korea, grain demands are heavily dependent on imports, with the share of imports from the U.S. at a particularly high level today. Hence, it is necessary to conduct continuous prediction on food security level following the climate change, as well as to develop adaptation strategy and proper agricultural policy.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.348-358
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• 2015

Impacts of climate change are being observed in the globe as well as the Korean peninsula. In the past 100 years, the average temperature of the earth rose about 0.75 degree in celsius, while that of Korean peninsula rose about 1.5 degree in celsius. The fifth Assessment Report of IPCC(Intergovermental Panel on Climate Change) predicts that the water pollution will be aggravated by change of hydrologic extremes such as floods and droughts and increase of water temperature (KMA and MOLIT, 2009). In this study, future runoff was calculated by applying climate change scenario to analyze the future water quality for each targe period (Obs : 2001 ~ 2010, Target I : 2011 ~ 2040, Target II : 2041 ~ 2070, Target III : 2071 ~ 2100) in Hongcheon river basin, Korea. In addition, The future water quality was analyzed by using multiple linear regression analysis and artificial neural networks after flow-duration curve analysis. As the results of future water quality prediction in Hongcheon river basin, we have known that BOD, COD and SS will be increased at the end of 21 century. Therefore, we need consider long-term water and water quality management planning and monitoring for the improvement of water quality in the future. For the prediction of more reliable future water quality, we may need consider various social factors with climate components.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1135-1148
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• 2018

Previous studies on reservoir operation have been assumed that the climate in the future would be similar to that in the past. However, in the presence of climate non-stationarity, Robust Optimization (RO) which finds the feasible solutions under broader uncertainty is necessary. RO improves the existing optimization method by adding a robust term to the objective function that controls the uncertainty inherent due to input data instability. This study proposed Robust-SDP that combines Stochastic Dynamic Programming (SDP) and RO to estimate dam operation rules while coping with climate non-stationarity. The future inflow series that reflect climate non-stationarity were synthetically generated. We then evaluated the capacity of the dam operation rules obtained from the past inflow series based on six evaluation indicators and two decision support schemes. Although Robust-SDP was successful in reducing the incidence of extreme water scarcity events under climate non-stationarity, there was a trade-off between the number of extreme water scarcity events and the water scarcity ratio. Thus, it is proposed that decision-makers choose their optimal rules in reference to the evaluation results and decision support illustrations.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.297-304
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• 2020

BACKGROUND: Emission of nitrous oxide (N2O) from the soil is expected to depend on the types of nitrogen fertilizer used. Biochar has recently been proposed as a potential mitigation of climate change by reducing the N2O emission. Although laboratory studies reported that biochar applications could reduce N2O emission, the number of field-based studies is still limited. Therefore, a field experiment was conducted to investigate the effect of biochar on N2O emission when different nitrogen fertilizers were applied in corn cultivated field. METHODS AND RESULTS: The field experiment consisted of six treatments: urea fertilizer without biochar (U), ammonium sulfate fertilizer without biochar (A), oil cake fertilizer without biochar (O), urea fertilizer with biochar (U+B), ammonium sulfate fertilizer with biochar (A+B), and oil cake fertilizer with biochar (O+B). Biochar was applied at a rate of 10 t/ha. Greenhouse gas fluxes were measured during growing seasons using static vented chambers. The cumulative N2O emissions were 0.99 kg/ha in the U, 1.23 kg/ha in the A, 3.25 kg/ha in the O, 1.19 kg/ha in the U+B, 0.86 kg/ha in the A+B, and 1.55 kg/ha in the O+B. CONCLUSION: It was found that N2O emission was related to application of both nitrogen fertilizer type and biochar. In particular, the N2O reduction effect was the highest in the corn field incorporated with biochar when oil cake was applied to the soil.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.14-26
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• 2021

Increase of climate variability due to climate change has paved the way for regional drought monitoring and outlook. In particular, Gimcheon-si, Gyeongsangbuk-do, is suffering from frequent and periodic drought damage as the frequency and magnitude of drought are increasing due to climate change. For this reason, it is necessary to analyze drought characteristics for sub-districts based on water district and calculate the basic low-flow considering climate change. In this study, meteorological and hydrological drought outlook were carried out for 8 sub-districts considering the water supply system and regional characteristics of Gimcheon-si according to various climate change scenarios. In addition, the low-flow frequency analysis for the near future was also performed using the total amount of runoff and the low-flow. The overall results indicated that, meteorological droughts were found to be dangerous in the S0(1974~2019) period and hydrological droughts would be dangerous in the S2(2041~2070) period for RCP 4.5 and in S3(2071~2099) period for RCP 8.5. The results of low-flow frequency analysis indicated that future runoff would increase but drought magnitude and frequency would increase further. The results and methodology may be useful for preparing local governments' drought measures and design standards for local water resources facilities.