• Title/Summary/Keyword: general circulation

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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.

Development of Oceanic General Circulation Model for Climate Change Prediction (기후변화예측을 위한 해양대순환모형의 개발)

  • Ahn, Joong-Bae;Lee, Hyo-Shin
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.3 no.1
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    • pp.16-24
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    • 1998
  • In this study, Ocean General Circulation Model (OGCM) has been developed as a counterpart of Atmospheric General Circulation (AGCM) for the study of coupled ocean-atmosphere climate system. The oceanic responses to given atmospheric boundary conditions have been investigated using the OGCM. In an integration carried out over 100 simulated years with climatological monthly mean data (EXP 1), most parts of the model reached a quasi-equilibrium climate reproducing many of the observed large-scale oceanic features remarkably well. Some observed narrow currents, however, such as North Equatorial Counter Current, were inevitably distorted due to the model's relatively coarse resolution. The seasonal changes in sea ice cover over the southern oceans around Antarctica were also simulated. In an experiment (EXP 2) under boundary condition of 10-year monthly data (1982-1991) from NCEP/NCAR Reanalysis Project model properly reproduced major oceanic changes during the period, including El Ni$\tilde{n}$os of 1982-1983 and 1986-87. During the ENSO periods, the experiment showed eastward expansion of warm surface waters and a negative vertical velocity anomalies along' the equator in response to expansion of westerly current velocity anomalies as westerly wind anomalies propagated eastward. Simulated anomalous distribution and the time behavior in response to El Ni$\tilde{n}$o events is consistent with that of the observations. These experiments showed that the model has an ability to reproduce major mean and anomalous oceanic features and can be effectively used for the study of ocean-atmosphere coupling system.

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A Correction of East Asian Summer Precipitation Simulated by PNU/CME CGCM Using Multiple Linear Regression (다중 선형 회귀를 이용한 PNU/CME CGCM의 동아시아 여름철 강수예측 보정 연구)

  • Hwang, Yoon-Jeong;Ahn, Joong-Bae
    • Journal of the Korean earth science society
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    • v.28 no.2
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    • pp.214-226
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    • 2007
  • Because precipitation is influenced by various atmospheric variables, it is highly nonlinear. Although precipitation predicted by a dynamic model can be corrected by using a nonlinear Artificial Neural Network, this approach has limits such as choices of the initial weight, local minima and the number of neurons, etc. In the present paper, we correct simulated precipitation by using a multiple linear regression (MLR) method, which is simple and widely used. First of all, Ensemble hindcast is conducted by the PNU/CME Coupled General Circulation Model (CGCM) (Park and Ahn, 2004) for the period from April to August in 1979-2005. MLR is applied to precipitation simulated by PNU/CME CGCM for the months of June (lead 2), July (lead 3), August (lead 4) and seasonal mean JJA (from June to August) of the Northeast Asian region including the Korean Peninsula $(110^{\circ}-145^{\circ}E,\;25-55^{\circ}N)$. We build the MLR model using a linear relationship between observed precipitation and the hindcasted results from the PNU/CME CGCM. The predictor variables selected from CGCM are precipitation, 500 hPa vertical velocity, 200 hPa divergence, surface air temperature and others. After performing a leave-oneout cross validation, the results are compared with the PNU/CME CGCM's. The results including Heidke skill scores demonstrate that the MLR corrected results have better forecasts than the direct CGCM result for rainfall.

Prioritizing the target watersheds for permeable pavement to reduce flood damage in urban watersheds considering future climate scenarios (미래 기후 시나리오를 고려한 도시 유역 홍수 피해 저감을 위한 투수성 포장 시설 대상 유역 우선순위 선정)

  • Chae, Seung Taek;Song, Young Hoon;Lee, Joowon;Chung, Eun-Sung
    • Journal of Korea Water Resources Association
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    • v.55 no.2
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    • pp.159-170
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    • 2022
  • As the severity of water-related disasters increases in urban watersheds due to climate change, reducing flood damage in urban watersheds is one of the important issues. This study focuses on prioritizing the optimal site for permeable pavement to maximize the efficiency of reducing flood damage in urban watersheds in the future climate environment using multi-criteria decision making techniques. The Mokgamcheon watershed which is considerably urbanized than in the past was selected for the study area and its 27 sub-watersheds were considered as candidate sites. Six General Circulation Model (GCM) of Coupled Model Intercomparison Project 6(CMIP6) according to two Shared Socioeconomic Pathway (SSP) scenarios were used to estimate future monthly precipitation for the study area. The Driving force-Pressure-State-Impact-Response (DPSIR) framework was used to select the water quantity evaluation criteria for prioritizing permeable pavement, and the study area was modeled using ArcGIS and Storm Water Management Model (SWMM). For the values corresponding to the evaluation criteria based on the DPSIR framework, data from national statistics and long-term runoff simulation value of SWMM according to future monthly precipitation were used. Finally, the priority for permeable pavement was determined using the Fuzzy TOPSIS and Minimax regret method. The high priorities were concentrated in the downstream sub-watersheds where urbanization was more progressed and densely populated than the upstream watersheds.

A Comparative Study on the Patient Behavior of Corridor Space on the Ward in General Hospital in Korea - Focused on the Courtyard and Double-loaded Corridor type - (국내 종합병원 병동부 복도공간의 환자 이용행태에 관한 비교 연구 - 중정형과 중복도형을 중심으로 -)

  • Lee, Hong-Sik;Kim, Sang-Bok;Yang, Nae-Won
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.11 no.3
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    • pp.31-39
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    • 2005
  • The conventional corridor space was a functional space simply linking the rooms and facilitating the circulations in a hospital. Today, however, they are no longer the spaces for simple circulation. Now, they are changing into healing spaces. Healing space must have some spatial characteristics helpful to curing the patients, and therefore, such a space should be designed to encourage patients to have diverse experiences and behaviors in terms of psychological stability, rehabilitation and personal communication. With such basic conceptions in mind, this study was aimed at surveying and analyzing patients' behaviors of using the corridor spaces for general hospital wards. To this end, middle corridors and patio-type side corridors for general hospital wards in Korea were sampled. It was found through this study that various healing behaviors shown in the conventional middle corridors were witnessed in the patio-type side corridors. On the other hand, behavioral characteristics of each area were analyzed to determine the factors encouraging patients to be cured, and thereupon, some design points for the corridor spaces of general hospital wards were suggested to help their users quick recovering.

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A Study on the 4-level quasi-geostropic numerical model (4층 준지균 수치모형에 관한 연구)

  • 이우진;이천우
    • Water for future
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    • v.17 no.3
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    • pp.211-219
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    • 1984
  • A 4-level baroclinic numerical model is designed by using the vorticity equation and Omega equation. Block-Cyclic-Reduction method is applied to the solution of the Helmholtz defferential equation, which is proved to be better than the Relaxation method from the composite viewpoint of accuracy, stability and economy. It was investigated whether the model explains the physical process influenced by voricity and temperature advection. It was also examined if the model atmosphere describes the general circulation. This examination is similar to Phillips(1956). The result of this numerical experiment shows that the model explains qualitatively the Quasi-Geostrophic theory for the development of Baroclinic wave, as throughly described in Holton(1972).

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Total Anomalous Pulmonary Venous Connection in Adult -A Case Report- (성인 총폐정맥 환류이상 -1례 보고-)

  • 김덕실
    • Journal of Chest Surgery
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    • v.28 no.12
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    • pp.1174-1177
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    • 1995
  • We experienced one case of TAPVC patient who was 39 years old man with mild dyspnea on exertion and easy fatigability. He was the oldest patient among TAPVC which was reported in Korea. Preoperative echocardiogram, cardiac catheterization and angiogram revealed supracardiac type TAPVC drained through left innominate vein. An anastomosis between common pulmonary venous trunk and left atrium, pericardial patch closure of ASD and ligation of left vertical vein were performed with extracorporeal circulation. The postoperative course was uneventful and discharged with excellent general condition and has been well during 8 months follow-up.

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심장 부정맥을 동반한 하악 전돌증 환자의 술전준비와 악교정수술

  • Yu, Jeong-Taek;Kim, Cheol;Song, Seon-Heon
    • The Journal of the Korean dental association
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    • v.40 no.9 s.400
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    • pp.703-708
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    • 2002
  • Cardiac arrhythmia is irregular heart rate. It's one of the reason of unpredictable sudden death. Accurate diagnosis and management of cardiac arrhythmia are the most important factors for the life of patient. To obtain a good prognosis, Dentist should be know and manage the multi-types of cardiac arrhythmia during dental treatment with the cooperation of medical doctor majored in cardiac circulation medicine. We casually found the cardiac arrhythmia in mandible prognathism patient during preparation for orthognathic surgery. Orthognathic surgery for cardiac arrhythmia patient was done successfully under general anesthesia with the temporary cardiac pace-maker.

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On Tidal Energy Horizontal Circulation

  • Nekrasov, A.V.
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 1992.08a
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    • pp.69-71
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    • 1992
  • The local horizintal flux of tidal energy is characterized by the surface density $\omega$ = $\rho$ g h ζ u ($\rho$ - sea water density, g - gravitation, h - depth, ζ - tidal surface elevation, u - vertically averaged tidal current velocity vector). In general the flux vector $\omega$ comprises active and reactive components whose relation determines the local structure of a tidal wave.(omitted)

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