• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.108-125
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• 2015

The agro-climatic index is one of the ways to assess the climate resources of particular agricultural areas on the prospect of agricultural production; it can be a key indicator of agricultural productivity by providing the basic information required for the implementation of different and various farming techniques and practicalities to estimate the growth and yield of crops from the climate resources such as air temperature, solar radiation, and precipitation. However, the agro-climate index can always be changed since the index is not the absolute. Recently, many studies which consider uncertainty of future climate change have been actively conducted using multi-model ensemble (MME) approach by developing and improving dynamic and statistical downscaling of Global Climate Model (GCM) output. In this study, the agro-climatic index of Korean Peninsula, such as growing degree day based on $5^{\circ}C$, plant period based on $5^{\circ}C$, crop period based on $10^{\circ}C$, and frost free day were calculated for assessment of the spatio-temporal variations and uncertainties of the indices according to climate change; the downscaled historical (1976-2005) and near future (2011-2040) RCP climate sceneries of AR5 were applied to the calculation of the index. The result showed four agro-climatic indices calculated by nine individual GCMs as well as MME agreed with agro-climatic indices which were calculated by the observed data. It was confirmed that MME, as well as each individual GCM emulated well on past climate in the four major Rivers of South Korea (Han, Nakdong, Geum, and Seumjin and Yeoungsan). However, spatial downscaling still needs further improvement since the agro-climatic indices of some individual GCMs showed different variations with the observed indices at the change of spatial distribution of the four Rivers. The four agro-climatic indices of the Korean Peninsula were expected to increase in nine individual GCMs and MME in future climate scenarios. The differences and uncertainties of the agro-climatic indices have not been reduced on the unlimited coupling of multi-model ensembles. Further research is still required although the differences started to improve when combining of three or four individual GCMs in the study. The agro-climatic indices which were derived and evaluated in the study will be the baseline for the assessment of agro-climatic abnormal indices and agro-productivity indices of the next research work.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.83-96
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• 2018

The objective of this study was to estimate the climate change impact on water quantity and quality to Saemanguem watershed using SWAT (Soil and water assessment tool) model. The SWAT model was calibrated and validated using observed data from 2008 to 2017 for the study watershed. The $R^2$ (Determination coefficient), RMSE (Root mean square error), and NSE (Nash-sutcliffe efficiency coefficient) were used to evaluate the model performance. RCP scenario data were produced from 10 GCM (General circulation model) and all relevant grid data including the major observation points (Gusan, Jeonju, Buan, Jeongeup) were extracted. The systematic error evaluation of the GCM model outputs was performed as well. They showed various variations based on analysis of future climate change effects. In future periods, the MIROC5 model showed the maximum values and the CMCC-CM model presented the minimum values in the climate data. Increasing rainfall amount was from 180mm to 250mm and increasing temperature value ranged from 1.7 to $5.9^{\circ}C$, respectively, compared with the baseline (2006~2017) in 10 GCM model outputs. The future 2030s and 2070s runoff showed increasing rate of 16~29% under future climate data. The future rate of change for T-N (Total nitrogen) and T-P (Total phosphorus) loads presented from -26 to +0.13% and from +5 to 47%, respectively. The hydrologic cycle and water quality from the Saemanguem headwater were very sensitive to projected climate change scenarios so that GCM model should be carefully selected for the purpose of use and the tendency analysis of GCM model are needed if necessary.

• Journal of Environmental Science International
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• v.29 no.9
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• pp.871-883
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• 2020

Due to recent heavy rain events, there are increasing demands for adapting infrastructure design, including drainage facilities in urban basins. Therefore, a clear definition of urban rainfall must be provided; however, currently, such a definition is unavailable. In this study, urban rainfall is defined as a rainfall event that has the potential to cause water-related disasters such as floods and landslides in urban areas. Moreover, based on design rainfall, these disasters are defined as those that causes excess design flooding due to certain rainfall events. These heavy rain scenarios require that the design of various urban rainfall facilities consider design rainfall in the target years of their life cycle, for disaster prevention. The average frequency of heavy rain in each region, inland and coastal areas, was analyzed through a frequency analysis of the highest annual rainfall in the past year. The potential change in future rainfall intensity changes the service level of the infrastructure related to hand-to-hand construction; therefore, the target year and design rainfall considering the climate change premium were presented. Finally, the change in dimensional safety according to the RCP8.5 climate change scenario was predicted.

• Journal of Korea Water Resources Association
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• v.47 no.3
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• pp.269-283
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• 2014

This study evaluated the environmental impact based on watershed characteristics and climate change using RCP climate change scenarios provided by the Korea Meteorological Administration. Future dam inflow was estimated by the SWAT model. Dam safety evaluation and downstream duration curve analysis was performed using HEC-ResSim model. Trends of water quality was analyzed through seasonal-Kendall Test using existing water quality observation data. Release discharge and tributary runoff derived SWAT and HEC-ResSim models applied to Qual2E and the future change in water quality trends were analyzed. Integrated environmental review watershed following techniques will be able to obtain the river environment management system and environmental issues such as climate change, new guidelines for preemptively response will be provided.

• Journal of Environmental Impact Assessment
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• v.22 no.1
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• pp.39-50
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• 2013

Occurrence of landslides has been increasing due to extreme weather events(e.g. heavy rainfall, torrential rains) by climate change. Pyeongchang, Korea had seriously been damaged by landslides caused by a typhoon, Ewiniar in 2006. Moreover, the frequency and intensity of landslides are increasing in summer due to torrential rain. Therefore, risk assessment and adaptation measure is urgently needed to build resilience. To support landslide adaptation measures, this study predicted landslides occurrence using MaxEnt model and suggested susceptibility map of landslides. Precipitation data of RCP 8.5 Climate change scenarios were used to analyze an impact of increase in rainfall in the future. In 2050 and 2090, the probability of landslides occurrence was predicted to increase. These were due to an increase in heavy rainfall and cumulative rainfall. As a result of analysis, factors that has major impact on landslide appeared to be climate factors, prediction accuracy of the model was very high(92%). In the future Pyeongchang will have serious rainfall compare to 2006 and more intense landslides area expected to increase. This study will help to establish adaptation measure against landslides due to heavy rainfall.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.683-696
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• 2013

Recent inundation damage has frequently occurred due to heavy rainfall in urban area, because rainfall has locally occurred exceeding the capability of a flood control plan by the exiting design rainfall from the data of Seoul weather station. Accordingly the objective of this study is to predict new design rainfall in order to make a future flood control plan considering climate change. In this study, for considering spatial characteristics of rainfall in urban area, data of AWS was used and for retaining insufficient rainfall data, WGR model was estimated the application of target area. The results were compared with the observation data and consequently show reasonable results. In addition, to prepare for climate change, design rainfall was calculated by applying for various climate scenarios and the result would be used in order to establish future flood control plan.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.145-145
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• 2018

Small islands rely heavily on groundwater resources in addition to rainwater as the source of freshwater since surface water bodies are often absent. The groundwater resources are vulnerable to sea level rise, coastal flooding, saltwater intrusion, irregular pattern of precipitation resulting in long droughts and flash floods. Increase in population increases the demand for the limited groundwater resources, thus aggravating the problem. In this study, the effects of climate change on Tongatapu Island, Kingdom of Tonga, a small island in Pacific Ocean, are investigated using a sharp interface transient groundwater flow model. Twenty nine downscaled General Circulation Model(GCM) predictions are input to a water balance model to estimate the groundwater recharge. The temporal variation in recharge is predicted over the period of 2010 to 2099. A set of GCM models are selected to represent the ensemble of 29 models based on cumulative recharge at the end of the century. This set of GCM model predictions are then used to simulate a total of six climate scenarios, three each (2010-2039, 2040-2069, and 2070-2099) under RCP 4.5 and RCP 8.5. The impacts of predicted climate change on groundwater resources is evaluated in terms of freshwater volume changes and saltwater ratios in pumping wells compared to present conditions. Though the cumulative recharge at the end of the century indicates a wetter climate compared to the present conditions the large variability in rainfall pattern results in frequent periods of groundwater drought leading to saltwater intrusion in pumping wells. Thus for sustaining the limited groundwater resources in small islands, implementation of timely assessment and management practices are of utmost importance.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.594-598
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• 2016

기후변화는 사회 경제 환경부분에 영향을 미치며 수자원 부문에서는 안정적인 물 공급에 위기가 발생할 것으로 전망되고 있다. 인간이 이용하는 수자원은 강우에 의해 가장 민감하게 반응하므로 지속적이고 안정적인 수자원을 이용하기 위해서는 통합적이고 탄력적인 대응방안이 요구되고 있다. 특히 우리나라와 같은 여름에 집중적 강우가 나타나는 지역에서의 용수수급에 대한 중요성은 더욱더 커질 것이다. 또한 앞으로 1인당 물 수요량의 증가할 것으로 예상됨에 따라 용수수급 관리를 위한 적응전략 수립은 반드시 필요할 것이다. 본 연구에서는 수문모형인 SWAT을 이용하여 자연유량을 산출하기 위해 SWAT-CUP을 이용한 검보정을 수행하여 모형의 적용성을 검토하였다. 기후변화 시나리오인 RCP시나리오를 이용하여 기간별 자연유량을 산정하였다. 유역의 생활용수, 공업용수, 농업용수 및 하천유지유량 데이터를 수집하여 물 분배 모형인 K-MODSIM 모형에 적용하였다. 2011년부터 2100년까지 월별로 유역의 물 수급의 과부족을 산정하였다. 용수의 부족이 나타난 지역에 대한 수요관리와 공급관리 방안을 수립하였고 대안을 적용한 후 용수 공급에 미치는 영향을 다시 분석하였다. 수문모의 결과 RCP 시나리오별로 자연유량을 산정한 결과 시간의 흐름에 따라 물 공급량이 감소할 것으로 분석되었고 계절별로 차이는 더 크게 나타났다. 특히 갈수기인 봄과 겨울철의 유량감소가 나타났다. 모의된 월별 자연유량을 K-MODSIM에 입력하여 월별 모의를 수행한 결과 각 용수별로 부족현상이 나타났다. 생활용수의 부족이 나타난 경우 수요관리를 통해 물 수요량을 줄이는 적응전략을 수립하였고 부족량이 크게 나타나는 농업용수와 하천유지유량의 경우 공급량을 늘리는 공급관리를 통한 적응전략을 수립하여 효과분석을 수행하였다. 단계별로 용수공급에 대한 효과가 나타났다. 하지만 본 연구에서는 경제성 분석을 제외한 용수공급에 중점을 둔 적응전략을 수립하였으므로 이를 포함한 분석이 포함된다면 실제 용수공급 대안 선정을 위한 의사결정에 도움이 될 수 있을 것이다.

• Journal of Environmental Impact Assessment
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• v.26 no.5
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• pp.291-302
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• 2017

The research was carried out in order to find climate factors which determine the distribution of Eurya japonica, and the potential habitats (PHs) under the current climate and climate change scenario by using species distribution models (SDMs). Four climate factors; the warmth index (WI), the minimum temperature of the coldest month (TMC), summer precipitation (PRS), and winter precipitaion (PRW) : were used as independent variables for the model. Seventeen general circulation models under RCP (Representative concentration pathway) 8.5 scenarios were used as future climate scenarios for the 2050s (2040~2069) and 2080s (2070~2099). Highly accurate SDMs were obtained for E. japonica. The model of distribution for E. japonica constructed by SDMs showed that minimum temperature of the coldest month (TMC) is a major climate factor in determining the distribution of E. japonica. The area above the $-5.7^{\circ}C$ of TMC revealed high occurrence probability of the E. japonica. Future PHs for E. japonica were projected to increase respectively by 2.5 times, 3.4 times of current PHs under 2050s and 2080s. It is expected that the potential of E. japonica habitats is expanded gradually. E. japonica is applicable as indicator species for monitoring in the Korean Peninsula. E. japonica is necessary to be monitored of potential habitats.

• Journal of Korea Water Resources Association
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• v.53 no.4
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• pp.249-258
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• 2020

Many climate studies have used the general circulation models (GCMs) for climate change, which can be currently available more than sixty GCMs as part of the Assessment Report (AR5). There are several types of uncertainty in climate studies using GCMs. Various studies are currently being conducted to reduce the uncertainty associated with GCMs, and the bias correction method used to reduce the difference between the simulated and the observed rainfall. Therefore, this study mainly considered climate change scenarios from nine GCMs, and then quantile mapping methods were applied to correct biases in climate change scenarios for each station during the historical period (1970-2005). Moreover, the monthly rainfall for the future period (2011-2100) is obtained from the RCP 4.5 scenario. Based on the bias-corrected rainfall, the standard deviation and the inter-quartile range (IQR) from the first to third quartiles were estimated. For 2071-2100, the uncertainty for the selection of GCMs is larger than that for the selection of bias correction methods and vice versa for 2011-2040. Therefore, this study showed that the selection of GCMs and the bias correction methods can affect the result for the future climate projection.