• Title/Summary/Keyword: General circulation model (GCM)

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Selection framework of representative general circulation models using the selected best bias correction method (최적 편이보정 기법의 선택을 통한 대표 전지구모형의 선정)

  • Song, Young Hoon;Chung, Eun-Sung;Sung, Jang Hyun
    • Journal of Korea Water Resources Association
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    • v.52 no.5
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    • pp.337-347
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    • 2019
  • This study proposes the framework to select the representative general circulation model (GCM) for climate change projection. The grid-based results of GCMs were transformed to all considered meteorological stations using inverse distance weighted (IDW) method and its results were compared to the observed precipitation. Six quantile mapping methods and random forest method were used to correct the bias between GCM's and the observation data. Thus, the empirical quantile which belongs to non-parameteric transformation method was selected as a best bias correction method by comparing the measures of performance indicators. Then, one of the multi-criteria decision techniques, TOPSIS (Technique for Order of Preference by Ideal Solution), was used to find the representative GCM using the performances of four GCMs after the bias correction using empirical quantile method. As a result, GISS-E2-R was the best and followed by MIROC5, CSIRO-Mk3-6-0, and CCSM4. Because these results are limited several GCMs, different results will be expected if more GCM data considered.

Simulation Assessment of GCM Model in Case of Daily Precipitation and Temperature (일 강우량 및 기온 자료의 모의를 위한 GCM 모형의 평가)

  • Son, Minwoo;Byun, Jisun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.307-307
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    • 2019
  • General Ciculation Model (GCM) 모형에 대한 평가를 본 연구에서 수행한다. 모형의 적용을 위해서는 국지적 일 강우량 및 기온자료를 이용한다. 31개의 GCM 모의를 통해 도출되는 결과가 성능 평가에서 활용되었다. 일 최대, 최소 기온와 강우량이 파키스탄 지역을 대상으로 모의되었다. 모의를 위해서는 Gridded 데이터가 적용되었으며 각각 Asian Precipitation-Highly-Resolved Observational Data Integration Toward Evaluation, Berkeley Earth Surface Temperature, Princeton Global Meteorological Forcing, Climate Prediction Centre에 해당된다. GCM의 순위를 결정하기 위해서는 Symmetrical Uncertainty 방법이 이용된다. 결과를 통해서 Gridded 데이터의 종류에 따라 가장 높은 효율을 나타내는 GCM의 공간 분포가 달라진다는 점을 확인하였다. 이러한 특성은 기온과 강우량 자료 모두에서 확인된다. 기온의 경우에는 Commonwealth Scientific and Industrial Research Organization, Australia-MK3-6-0과 Max Planck Institute-ESM-LR이 우수한 결과를 모의하는 것으로 나타났다. 반면 강우량의 경우에는 EC-Earth와 MIROC가 우수한 것으로 나타났다. 파키스탄 지역에서의 기온 및 강우량 자료의 합리적 반영을 위해서는 ACCESS1-3, CESM1-BGC, CMCC-CM, HadGEM2-CC, HadGEM2-ES, MIRCO5와 같은 6개 GCM을 이용하였을 때 다양한 기상 인자를 고려한 모의가 가능한 것으로 평가된다.

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Intercomparison of uncertainty to bias correction methods and GCM selection in precipitation projections (강수량예측에서 편이보정방법과 GCM 선택에 대한 불확실성 비교)

  • Song, Young Hoon;Chung, Eun-Sung
    • 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.

A Study on Selection of Standard Scenarios in Korea for Climate Change (기후변화 표준 시나리오 선정에 관한 연구)

  • Lee, Jae-Kyoung;Kim, Young-Oh
    • Journal of Climate Change Research
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    • v.1 no.1
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    • pp.59-73
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    • 2010
  • One of the most important issues for projecting future water resources and establishing climate change adaptation strategies is 'uncertainty'. In Korea, climate change research results were very heterogeneous even in a same basin, but there have been few climate change studies dealt with the uncertainty reduction. This is because emission scenarios, GCMs, downscaling, and rainfall-runoff models that were used in the previous studies were almost all different. In this research, fifty one GCM scenarios based A and B emission scenarios were downloaded and then compared with the observed values for a period from January 2001 to December 2008. The downloaded GCM scenarios in general simulated well the observed but did not simulated well the observed precipitation especially for the flood season in Korea. The accuracy of each GCM scenario was measured with the model efficiency, PDF-based, and Relative Entropy methodology. Among the selected GCM scenarios with three methodologies, the four common GCM scenarios(CGCM2.3.2(MRI-M, B1), MIROC3.2medress(NIES, B1), CGCM2.3.2(MRI-M, A2), CGCM2.3.2(MRI-M, A1B) were finally selected. Results of the four selected GCMs were heterogeneity and projected increases of precipitation for the Korean Peninsula by from 27.36% to 12.49%, respectively. It seems very risky to rely a water planning or a management policy on use of a single climate change scenario and from this research results. Therefore, the four selected GCM scenarios proposed quantitatively were considered firstly for the water supply in the dry season and the drought management strategy in the Korean Peninsula for the future.

Utility of Climate Model Information For Water Resources Management in Korea

  • Jeong, Chang-Sam
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.6
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    • pp.37-45
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    • 2008
  • It is expected that conditions of water resources will be changed in Korea in accordance with world wide climate change. In order to deal with this problem and find a way of minimizing the effect of future climate change, the usefulness of climate model simulation information is examined in this study. The objective of this study is to assess the applicability of GCM (General Circulation Model) information for Korean water resources management through uncertainty analysis. The methods are based on probabilistic measures of the effectiveness of GCM simulations of an indicator variable for discriminating high versus low regional observations of a target variable. The formulation uses the significance probability of the Kolmogorov-Smirnov test for detecting differences between two variables. An estimator that accounts for climate model simulation and spatial association between the GCM data and observed data is used. Atmospheric general circulation model (AGCM) simulations done by ECMWF (European Centre for Medium-Range Weather Forecasts) with a resolution of $2^{\circ}{\times}2^{\circ}$, and METRI (Meteorological Research Institute, Korea) with resolutions of $2^{\circ}{\times}2^{\circ}$ and $4^{\circ}{\times}5^{\circ}$, were used for indicator variables, while observed mean areal precipitation (MAP) data, discharge data and mean areal temperature data on the seven major river basins in Korea were used for target variables. The results show that GCM simulations are useful in discriminating the high from the low of the observed precipitation, discharge, and temperature values. Temperature especially can be useful regardless of model and season.

Assessing the skills of CMIP5 GCMs in reproducing spatial climatology of precipitation over the coastal area in East Asia (CMIP5 GCM의 동아시아 해안지역에 대한 공간적 강우특성 재현성 평가)

  • Hwang, Syewoon;Cho, Jeapil;Yoon, Kwang Sik
    • Journal of Korea Water Resources Association
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    • v.51 no.8
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    • pp.629-642
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    • 2018
  • Future variability of the spatial patterns of rainfall events is the point of water-related risks and impacts of climate change. Recent related researches are mostly conducted based on the outcomes from General Circulation Models (GCMs), especially Coupled Model Intercomparison Project, phase 5 (CMIP5) GCMs which are the most advanced version of climate modeling system. GCM data have been widely used for various studies as the data utility keep getting improved. Meanwhile the model performances especially for raw GCM outputs are rarely evaluated prior to the applications although the process would essential for reasonable use of model forecasts. This study attempt to quantitatively evaluate the skills of 29 CMIP5 GCMs in reproducing spatial climatologies of precipitation in East Asia. We used 3 different gridded observational data as the references available over the study area and calculated correlation and errors of spatial patterns simulated by GCMs. As a result, the study presented diversity of the GCM evaluation in the performance, rank, or accuracy by different configurations, such as target area, evaluation method, and observation data. Yet, we found that Hadley-centre affiliated models comparatively performs better for the meso-scale area in East Asia and MPI_ESM_MR and CMCC family showed better performance specifically for the korean peninsula. We expect that the results and thoughts of this study would be considered in screening suitable GCMs for specific area, and finally contribute to extensive utilization of the results from climate change related researches.

Effects of Climate Change on the Streamflow for the Daechung Dam Watershed (기후변화에 따른 대청댐 유역의 유출 영향 분석)

  • Kim, Ung-Tae;Lee, Dong-Ryul;Yoo, Chul-Sang
    • Journal of Korea Water Resources Association
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    • v.37 no.4
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    • pp.305-314
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    • 2004
  • Climate change mainly due to the increase of green house gases cause different patterns of water cycle within the basin. However, it is common that current planning and management practices do not consider the effect of the climate change. So, this study evaluated the effect of climate change on the water circulation within the watershed. This study used several GCM simulations for the double $CO_2$condition for the generation of temperature and rainfall series using the Markov chain. Daily runoff series for 100 years were generated using a rainfall-runoff model. As results. annual temperature increase by +3.2 ∼+4.6$^{\circ}C$, annual precipitation change -7 ∼ +8 %, annual runoff change -14 ∼ +7 %, and potential evapotranspiration amount change +3 ∼+4 % for the change of 1 $^{\circ}C$ are found to be expected depending on GCM simulations. Even though the simulation results are very dependent on the GCM predictions considered, overall variability of runoff is expected to become higher than the current state.

Uncertainty assessment caused by GCMs selection on hydrologic studies

  • Ghafouri-Azar, Mona;Bae, Deg-Hyo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2018.05a
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    • pp.151-151
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    • 2018
  • The present study is aimed to quantifying the uncertainty in the general circulation model (GCM) selection and its impacts on hydrology studies in the basins. For this reason, 13 GCMs was selected among the 26 GCM models of the Fifth Assessment Report (AR5) scenarios. Then, the climate data and hydrologic data with two Representative Concentration Pathways (RCPs) of the best model (INMCM4) and worst model (HadGEM2-AO) were compared to understand the uncertainty associated with GCM models. In order to project the runoff, the Precipitation-Runoff Modelling System (PRMS) was driven to simulate daily river discharge by using daily precipitation, maximum and minimum temperature as inputs of this model. For simulating the discharge, the model has been calibrated and validated for daily data. Root mean square error (RMSE) and Nash-Sutcliffe Efficiency (NSE) were applied as evaluation criteria. Then parameters of the model were applied for the periods 2011-2040, and 2070-2099 to project the future discharge the five large basins of South Korea. Then, uncertainty caused by projected temperature, precipitation and runoff changes were compared in seasonal and annual time scale for two future periods and RCPs compared to the reference period (1976-2005). The findings of this study indicated that more caution will be needed for selecting the GCMs and using the results of the climate change analysis.

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Development of Multi-Ensemble GCMs Based Spatio-Temporal Downscaling Scheme for Short-term Prediction (여름강수량의 단기예측을 위한 Multi-Ensemble GCMs 기반 시공간적 Downscaling 기법 개발)

  • Kwon, Hyun-Han;Min, Young-Mi;Hameed, Saji N.
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.1142-1146
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    • 2009
  • A rainfall simulation and forecasting technique that can generate daily rainfall sequences conditional on multi-model ensemble GCMs is developed and applied to data in Korea for the major rainy season. The GCM forecasts are provided by APEC climate center. A Weather State Based Downscaling Model (WSDM) is used to map teleconnections from ocean-atmosphere data or key state variables from numerical integrations of Ocean-Atmosphere General Circulation Models to simulate daily sequences at multiple rain gauges. The method presented is general and is applied to the wet season which is JJA(June-July-August) data in Korea. The sequences of weather states identified by the EM algorithm are shown to correspond to dominant synoptic-scale features of rainfall generating mechanisms. Application of the methodology to seasonal rainfall forecasts using empirical teleconnections and GCM derived climate forecast are discussed.

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Estimation of Global Warming by Coupled Atmosphere-Ocean GCM (대기/해양 접합 GCM을 이용한 지구 온난화의 추정)

  • Kim Jeong-Woo;Park Ji-Up
    • 한국전산유체공학회:학술대회논문집
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    • 2000.05a
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    • pp.14-19
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    • 2000
  • A coupled general circulation model (GCM) of the global atmosphere, oceans and lands is used for finding the future climate at times of doubled carbon dioxide concentration (DCDC) of the atmosphere. Two runs of the model were made in order to find the future change. Global changes at times of DCDC may be characterized by a global warmig of $1.4^{\circ}C$, a $3\%$ global precipitation increase, and an increase in the surface available water (SAW) over the global land among others. The estimated increase in SAW over the land implies that river discharge is likely to increase with increased chance of severe weather as a result of the future global warming.

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