• Journal of Climate Change Research
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• v.2 no.4
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• pp.237-251
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• 2011

This study presents a review on the recent climate change over the Korean peninsula, which has experienced a significant change due to the human-induced global warming more strongly than other regions. The recent measurement of carbon dioxide concentrations over the Korean peninsula shows a faster rise than the global average, and the increasing trend in surface temperature over this region is much larger than the global mean trend. Recent observational studies reporting the weakened cold extremes and intensified warm extremes over the region support consistently the increase of mean temperature. Surface vegetation greenness in spring has also progressed relatively more quickly. Summer precipitation over the Korean peninsula has increased by about 15% since 1990 compared to the previous period. This was mainly due to an increase in August. On the other hand, a slight decrease in the precipitation (about 5%) during Changma period (rainy season of the East Asian summer monsoon), was observed. The heavy rainfall amounts exhibit an increasing trend particularly since the late 1970s, and a consecutive dry-day has also increased primarily over the southern area. This indicates that the duration of precipitation events has shortened, while their intensity became stronger. During the past decades, there have been more stronger typhoons affecting the Korean peninsula with landing more preferentially over the southeastern area. Meanwhile, the urbanization effect is likely to contribute to the rapid warming, explaining about 28% of total temperature increase during the past 55 years. The impact of El Nino on seasonal climate over the Korean peninsula has been well established - winter [summer] temperatures was generally higher [lower] than normal, and summer rainfall tends to increase during El-Nino years. It is suggested that more frequent occurrence of the 'central-Pacific El-Nino' during recent decades may have induced warmer summer and fall over the Korean peninsula. In short, detection and attribution studies provided fundamental information that needed to construct more reliable projections of future climate changes, and therefore more comprehensive researches are required for better understanding of past climate variations.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.671-680
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• 2019

Many researches illustrated that the magnitude and frequency of hydrological event would increase in the future due to changes of hydrological cycle components according to climate change. However, few studies performed quantitative analysis and evaluation of future rainfall in North Korea, where the damage caused by extreme precipitation is expected to occur as in South Korea. Therefore, this study predicted the extreme precipitation change of North Korea in the future (2020-2060) compared to the current (1981-2017) using stationary and nonstationary frequency analysis. This study conducted nonstationary frequency analysis considering the external factors (mean precipitation of JFM (Jan.-Mar.), AMJ (Apr.-Jun.), JAS (Jul.-Sept.), OND (Oct.-Dec.)) of the HadGEM2-AO model simulated according to the Representative Concentration Pathway (RCP) climate change scenarios. In order to select external factors that have a similar tendency with extreme rainfall events in North Korea, the maximum annual rainfall data was obtained by using the ensemble empirical mode decomposition (EEMD) method. Correlation analysis was performed between the extracted residue and the external factors. Considering selected external factors, nonstationary GEV model was constructed. In RCP4.5, four of the eight stations tended to decrease in future extreme precipitation compared to the present climate while three stations increased. On the other hand, in RCP8.5, two stations decreased while five stations increased.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.441-441
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• 2015

북한의 수자원 현황을 분석하고 미래를 전망하는 일은 수자원 분야 전문가들의 공통된 관심사 중 하나이다. 그러나 많은 노력에도 불구하고 제한된 자료로 인해 이에 대한 체계적인 성과가 구축되지 못한 것이 사실이다(안재현 등, 2010). 북한 수자원 현황과 관련해서 1994년 한국수자원공사의"북한 수자원 현황 및 개발 동향"에 대한 연구와 1996년 한국과학기술단체총연합회의"남북한 수자원 비교평가 연구"가 수행된 바 있다. 본 연구에서는 2012년 7월 북한의 홍수피해에 대하여 북한지역의 빈약한 강우량 정보를 활용하여 위성으로부터 유도된 강우자료를 보정하여 북한지역의 홍수량을 산정하는데 활용할 수 있는 시계열 자료를 생성하는 것을 목적으로 하였다. 2012년 북한 홍수피해는 조선 중앙통신 보도에 의하면 6월 말부터 7월말까지 169명 사망, 400여명 실중, 144명 상해의 인명피해와 평안남북도, 자강도, 함경남북도 등 4만 3770여 가구가 침수되었으며, 농경지 피해는 6만 5280정보가 유실, 매몰, 침수(평안북도 2만 3400정보, 평안남도 2만 1900정보, 함경남도 5679정보, 함경북도 7220정보)의 피해를 입은 것으로 보도하고 있다(http://www.hani.co.kr/arti/politics/defense/545795.html). 한편, 북한의 기상수문국 통보에 의하면 2012년 장마가 시작된 이후 20일 동인 평균 강우량의 2배 가까운 비가 내렸으며, 특히 7월 19일 오후 9시부터 21일 오후 3시 사이 자강도 동신군에 413mm, 송원군에 383mm, 희천시에 322mm, 평안북도 태천군에 380mm, 향산군에 312mm, 동창군에 304mm의 폭우가 쏟아졌다고 조선중앙통신은 덧붙였다. 본 연구에서는 위성으로부터 유도된 강수자료 중 GSMaP_NRT자료를 활용하여 북한의 기상수문국에서 통보한 같이 기간의 강수량 자료를 분석한 결과 자강도 동신군 지역의 경우 총강우는 208.8mm로 분석되었으며, 평균강우는 9.49mm, 최대강우강도는 17.7mm/hr로 분석되었다. 두 자료의 총강우량에 대한 상대오차는 약 49.5% 정도의 오차가 있는 것으로 분석되었다. 위성강우 보정 방법으로 Immerzeel(2001) 등은 위성으로 관측된 시계열 자료와 지상계측된 시계열 자료를 분석하여 두 자료간의 평균과 표준편차를 이용하여 평균 및 표준편차 계수를 산정하여 위성자료에 대한 보정강우를 생성하는 방법을 제시한 바 있다. 본 연구에서는 위성으로부터 유도된 강우량 자료는 시계열 자료이나 지점계측 강우는 총강우만 존재하여 총강우에 대한 시계열 자료를 위성강수자료를 무차원화하여 지점계측의 위성 보정강우를 생성하였다.

• Journal of the Korean association of regional geographers
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• v.18 no.4
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• pp.473-493
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• 2012

Malaria infection is sensitively influenced by regional meteorological conditions along with global climate change. Remote sensing techniques have become an important tool for extraction of climatic and environmental factors, including rainfall, temperature, surface water, soil moisture, and land use, which are directly linked to the habitat qualities of malaria mosquitoes. Improvement of sensor fidelity with higher spatial and spectral resolution, new multinational sensor development, and decreased data cost have nurtured diverse remote sensing applications in malaria research. In 1984, eradication of endemic malaria was declared in Korea, but reemergence of malaria was reported in mid-1990s. Considering constant changes in malaria cases since 2000, the epidemiological management of the disease needs careful monitoring. Geographically, northmost counties neighboring North Korea have been ranked high in the number of malaria cases. High infection rates in these areas drew special attention and led to a hypothesis that malaria dispersion in these border counties might be caused by north-origin, malaria-bearing adult mosquitoes. Habitat conditions of malaria mosquitoes are important parameters for prediction of the vector abundance. However, it should be realized that malaria infection and transmission is a complex mechanism, where non-environmental factors, including human behavior, demographic structure, landscape structure, and spatial relationships between human residence and the vector habitats, are also significant considerations in the framework of medical geography.

• Journal of Korea Water Resources Association
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• v.49 no.2
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• pp.107-119
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• 2016

Since future climate scenarios indicate that extreme precipitation events will intensity, probable maximum precipitations (PMPs) without being taken climate change into account are very likely to be underestimated. In this study future PMPs in accordance with the variation of future rainfall are estimated. The hydro-meteorologic method is used to calculate PMPs. The orographic transposition factor is applied in place of the conventional terrain impact factor which has been used in previous PMPs estimation reports. Future DADs are indirectly obtained by using bias-correction and moving-averaged changing factor method based on daily precipitation projection under KMA RCM (HEDGEM3-RA) RCP 8.5 climate change scenario. As a result, future PMPs were found to increase and the spatially-averaged annual PMPs increase rate in 4-hour and $25km^2$ was projected to be 3 mm by 2045. In addition, the increased rate of future PMPs is growing increasingly in the future, but it is thought that the uncertainty of estimating PMPs caused by future precipitation projections is also increased in the distant future.

• Journal of Korea Water Resources Association
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• v.39 no.12 s.173
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• pp.1043-1056
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• 2006

Our ultimate purpose is to investigate the potential change in regional surface climate due to the global warming and to produce higher quality regional surface climate information over the Korean peninsula for comprehensive impact assessment. Toward this purpose, we carried out two 30-year long experiments, one for present day conditions (covering the period 1971-2000) and one for near future climate conditions (covering the period 2021-2050) with a regional climate model (RegCM3) using a one-way double-nested system. In order to obtain the confidence in a future climate projection, we first verify the model basic performance of how the reference simulation is realistic in comparison with a fairly dense observation network. We then examine the possible future changes in mean climate state as well as in the frequency and intensity of extreme climate events to be derived by difference between climate condition as a baseline and future simulated climate states with increased greenhouse gas. Emphasis in this study is placed on the high-resolution spatial/temporal aspects of the climate change scenarios under different climate settings over Korea generated by complex topography and coastlines that are relevant on a regional scale.

• Journal of Korea Water Resources Association
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• v.55 no.3
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• pp.205-215
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• 2022

Amidst the global climate crisis, dam operation policies formulated under the stationary climate assumption could lead to unsatisfactory water management. In this work, we assessed status-quo performance of the Yongdam Dam in Korea under various climatic stresses in flood risk reduction and water supply reliability for 2021-2040. To this end, we employed a decision-centric framework equipped with a stochastic weather generator, a conceptual streamflow model, and a machine-learning reservoir operation rule. By imposing 294 climate perturbations to dam release simulations, we found that the current operation rule of the Yongdam dam could redundantly secure water storage, while inefficiently enhancing the supply reliability. On the other hand, flood risks were likely to increase substantially due to rising mean and variability of daily precipitation. Here, we argue that the current operation rules of the Yongdam Dam seem to be overly focused on securing water storage, and thus need to be adjusted to efficiently improve supply reliability and reduce flood risks in downstream areas.

• Journal of Wetlands Research
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• v.15 no.2
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• pp.179-189
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• 2013

The Haean basin is a unique geographical feature formed by differential erosion and it borders the military demarcation line. Recently the basin has become an interest of civilians due to security tour, highland vegetables and wetland. After the civil war, the population decreased but it has increased since 2007. The annual mean air temperature in the basin has increased with a rate of $+0.016^{\circ}C/yr$ and the annual precipitation also has increased with a rate of +10.41 mm/yr. The precipitation occurring in June~August (wet season) occupied most of the total precipitation increase. In addition, recently the number of groundwater wells and its use have gradually increased and most of them are for agriculture including cultivation of rice and highland vegetables. If the air temperature further increases in the future according to the climate change scenarios, the highland vegetables cultivation will be difficult. Furthermore, if the rainstorm in the summer will be enforced, the groundwater recharge and water management will be aggravated. Therefore, an evaluation for sustainable groundwater development in the basin and a reform of the current agriculture (change of cultivating crops) depending on much water are essentially required.

• Atmosphere
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• v.22 no.2
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• pp.221-231
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• 2012

Representative Concentration Pathways (RCP) are the latest emission scenarios recommended to use for the fifth assessment report of Intergovernmental Panel on Climate Change. This study investigates the projection of extreme precipitation in South Korea during the forthcoming 21st Century using the generalized extreme value (GEV) analysis based on two different RCP conditions i.e., RCP 4.5 and 8.5. Maximum daily precipitation required for GEV analysis for RCP 4.5 and 8.5 are obtained from a high-resolution regional climate model forced by the corresponding global climate projections, which are produced within the CMIP5 framework. We found overall increase in frequency of extreme precipitation over South Korea in association with climate change. Particularly, daily extreme precipitation that has been occurred every 20 years in current climate (1980~2005) is likely to happen about every 4.3 and 3.4 years by the end of 21st Century (2070~2099) under the RCP 4.5 and 8.5 conditions, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.327-340
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• 2015

General Circulation Models (GCMs) are the basic tool used for modelling climate. However, the spatio-temporal discrepancy between GCM and observed value, therefore, the models deliver output that are generally required calibration for applied studies. Which is generally done by Multi-Model Ensemble (MME) approach. Stochastic downscaling methods have been used extensively to generate long-term weather sequences from finite observed records. A primary objective of this study is to develop a forecasting scheme which is able to make use of a MME of different GCMs. This study employed a Nonstationary Hidden Markov Chain Model (NHMM) as a main tool for downscaling seasonal ensemble forecasts over 3 month period, providing daily forecasts. Our results showed that the proposed downscaling scheme can provide the skillful forecasts as inputs for hydrologic modeling, which in turn may improve water resources management. An application to the Nakdong watershed in South Korea illustrates how the proposed approach can lead to potentially reliable information for water resources management.