• 제목/요약/키워드: and Simulation

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The Measurement of Sensitivity and Comparative Analysis of Simplified Quantitation Methods to Measure Dopamine Transporters Using [I-123]IPT Pharmacokinetic Computer Simulations ([I-123]IPT 약역학 컴퓨터시뮬레이션을 이용한 민감도 측정 및 간편화된 운반체 정량분석 방법들의 비교분석 연구)

  • Son, Hye-Kyung;Nha, Sang-Kyun;Lee, Hee-Kyung;Kim, Hee-Joung
    • The Korean Journal of Nuclear Medicine
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    • 제31권1호
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    • pp.19-29
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    • 1997
  • Recently, [I-123]IPT SPECT has been used for early diagnosis of Parkinson's patients(PP) by imaging dopamine transporters. The dynamic time activity curves in basal ganglia(BG) and occipital cortex(OCC) without blood samples were obtained for 2 hours. These data were then used to measure dopamine transporters by operationally defined ratio methods of (BG-OCC)/OCC at 2 hrs, binding potential $R_v=k_3/k_4$ using graphic method or $R_A$= (ABBG-ABOCC)/ABOCC for 2 hrs, where ABBG represents accumulated binding activity in basal ganglia(${\int}^{120min}_0$ BG(t)dt) and ABOCC represents accumulated binding activity in occipital cortex(${\int}^{120min}_0$ OCC(t)dt). The purpose of this study was to examine the IPT pharmacokinetics and investigate the usefulness of simplified methods of (BG-OCC)/OCC, $R_A$, and $R_v$ which are often assumed that these values reflect the true values of $k_3/k_4$. The rate constants $K_1,\;k_2\;k_3$ and $k_4$ to be used for simulations were derived using [I-123]IPT SPECT and aterialized blood data with a standard three compartmental model. The sensitivities and time activity curves in BG and OCC were computed by changing $K_l$ and $k_3$(only BG) for every 5min over 2 hours. The values (BG-OCC)/OCC, $R_A$, and $R_v$ were then computed from the time activity curves and the linear regression analysis was used to measure the accuracies of these methods. The late constants $K_l,\;k_2\;k_3\;k_4$ at BG and OCC were $1.26{\pm}5.41%,\;0.044{\pm}19.58%,\;0.031{\pm}24.36%,\;0.008{\pm}22.78%$ and $1.36{\pm}4.76%,\;0.170{\pm}6.89%,\;0.007{\pm}23.89%,\;0.007{\pm}45.09%$, respectively. The Sensitivities for ((${\Delta}S/S$)/(${\Delta}k_3/k_3$)) and ((${\Delta}S/S$)/(${\Delta}K_l/K_l$)) at 30min and 120min were measured as (0.19, 0.50) and (0.61, 0,23), respectively. The correlation coefficients and slopes of ((BG-OCC)/OCC, $R_A$, and $R_v$) with $k_3/k_4$ were (0.98, 1.00, 0.99) and (1.76, 0.47, 1.25), respectively. These simulation results indicate that a late [I-123]IPT SPECT image may represent the distribution of the dopamine transporters. Good correlations were shown between (3G-OCC)/OCC, $R_A$ or $R_v$ and true $k_3/k_4$, although the slopes between them were not unity. Pharmacokinetic computer simulations may be a very useful technique in studying dopamine transporter systems.

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Basic Research on the Possibility of Developing a Landscape Perceptual Response Prediction Model Using Artificial Intelligence - Focusing on Machine Learning Techniques - (인공지능을 활용한 경관 지각반응 예측모델 개발 가능성 기초연구 - 머신러닝 기법을 중심으로 -)

  • Kim, Jin-Pyo;Suh, Joo-Hwan
    • Journal of the Korean Institute of Landscape Architecture
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    • 제51권3호
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    • pp.70-82
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    • 2023
  • The recent surge of IT and data acquisition is shifting the paradigm in all aspects of life, and these advances are also affecting academic fields. Research topics and methods are being improved through academic exchange and connections. In particular, data-based research methods are employed in various academic fields, including landscape architecture, where continuous research is needed. Therefore, this study aims to investigate the possibility of developing a landscape preference evaluation and prediction model using machine learning, a branch of Artificial Intelligence, reflecting the current situation. To achieve the goal of this study, machine learning techniques were applied to the landscaping field to build a landscape preference evaluation and prediction model to verify the simulation accuracy of the model. For this, wind power facility landscape images, recently attracting attention as a renewable energy source, were selected as the research objects. For analysis, images of the wind power facility landscapes were collected using web crawling techniques, and an analysis dataset was built. Orange version 3.33, a program from the University of Ljubljana was used for machine learning analysis to derive a prediction model with excellent performance. IA model that integrates the evaluation criteria of machine learning and a separate model structure for the evaluation criteria were used to generate a model using kNN, SVM, Random Forest, Logistic Regression, and Neural Network algorithms suitable for machine learning classification models. The performance evaluation of the generated models was conducted to derive the most suitable prediction model. The prediction model derived in this study separately evaluates three evaluation criteria, including classification by type of landscape, classification by distance between landscape and target, and classification by preference, and then synthesizes and predicts results. As a result of the study, a prediction model with a high accuracy of 0.986 for the evaluation criterion according to the type of landscape, 0.973 for the evaluation criterion according to the distance, and 0.952 for the evaluation criterion according to the preference was developed, and it can be seen that the verification process through the evaluation of data prediction results exceeds the required performance value of the model. As an experimental attempt to investigate the possibility of developing a prediction model using machine learning in landscape-related research, this study was able to confirm the possibility of creating a high-performance prediction model by building a data set through the collection and refinement of image data and subsequently utilizing it in landscape-related research fields. Based on the results, implications, and limitations of this study, it is believed that it is possible to develop various types of landscape prediction models, including wind power facility natural, and cultural landscapes. Machine learning techniques can be more useful and valuable in the field of landscape architecture by exploring and applying research methods appropriate to the topic, reducing the time of data classification through the study of a model that classifies images according to landscape types or analyzing the importance of landscape planning factors through the analysis of landscape prediction factors using machine learning.

Radiation Therapy Using M3 Wax Bolus in Patients with Malignant Scalp Tumors (악성 두피 종양(Scalp) 환자의 M3 Wax Bolus를 이용한 방사선치료)

  • Kwon, Da Eun;Hwang, Ji Hye;Park, In Seo;Yang, Jun Cheol;Kim, Su Jin;You, Ah Young;Won, Young Jinn;Kwon, Kyung Tae
    • The Journal of Korean Society for Radiation Therapy
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    • 제31권1호
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    • pp.75-81
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    • 2019
  • Purpose: Helmet type bolus for 3D printer is being manufactured because of the disadvantages of Bolus materials when photon beam is used for the treatment of scalp malignancy. However, PLA, which is a used material, has a higher density than a tissue equivalent material and inconveniences occur when the patient wears PLA. In this study, we try to treat malignant scalp tumors by using M3 wax helmet with 3D printer. Methods and materials: For the modeling of the helmet type M3 wax, the head phantom was photographed by CT, which was acquired with a DICOM file. The part for helmet on the scalp was made with Helmet contour. The M3 Wax helmet was made by dissolving paraffin wax, mixing magnesium oxide and calcium carbonate, solidifying it in a PLA 3D helmet, and then eliminated PLA 3D Helmet of the surface. The treatment plan was based on Intensity-Modulated Radiation Therapy (IMRT) of 10 Portals, and the therapeutic dose was 200 cGy, using Analytical Anisotropic Algorithm (AAA) of Eclipse. Then, the dose was verified by using EBT3 film and Mosfet (Metal Oxide Semiconductor Field Effect Transistor: USA), and the IMRT plan was measured 3 times in 3 parts by reproducing the phantom of the head human model under the same condition with the CT simulation room. Results: The Hounsfield unit (HU) of the bolus measured by CT was $52{\pm}37.1$. The dose of TPS was 186.6 cGy, 193.2 cGy and 190.6 cGy at the M3 Wax bolus measurement points of A, B and C, and the dose measured three times at Mostet was $179.66{\pm}2.62cGy$, $184.33{\pm}1.24cGy$ and $195.33{\pm}1.69cGy$. And the error rates were -3.71 %, -4.59 %, and 2.48 %. The dose measured with EBT3 film was $182.00{\pm}1.63cGy$, $193.66{\pm}2.05cGy$ and $196{\pm}2.16cGy$. The error rates were -2.46 %, 0.23 % and 2.83 %. Conclusions: The thickness of the M3 wax bolus was 2 cm, which could help the treatment plan to be established by easily lowering the dose of the brain part. The maximum error rate of the scalp surface dose was measured within 5 % and generally within 3 %, even in the A, B, C measurements of dosimeters of EBT3 film and Mosfet in the treatment dose verification. The making period of M3 wax bolus is shorter, cheaper than that of 3D printer, can be reused and is very useful for the treatment of scalp malignancies as human tissue equivalent material. Therefore, we think that the use of casting type M3 wax bolus, which will complement the making period and cost of high capacity Bolus and Compensator in 3D printer, will increase later.

Usefulness of Pulsatile Flow Aortic Aneurysm Phantoms for Stent-graft Placement (스텐트그라프트 장치술을 위한 대동맥류 혈류 팬텀의 유용성)

  • Kim, Tae-Hyung;Ko, Gi-Young;Song, Ho-Young;Park, In-Kook;Shin, Ji-Hoon;Lim, Jin-Oh;Kim, Jin-Hyoung;Choi, Eu-Gene K.
    • Journal of radiological science and technology
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    • 제30권3호
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    • pp.205-212
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    • 2007
  • To evaluate the feasibility and efficacy of a pulsatile aortic aneurysm phantoms for in-vitro study. The phantoms consisted of a pulsating motor part(heart part) and an aortic aneurysm part, which mimicked true physiologic conditions. The heart part was created from a high-pressured water pump and a pulsatile flow solenoid valve for the simulation of aortic flow. The aortic aneurysm part was manufactured from paper clay, which was placed inside a acrylic plastic square box, where liquid silicone was poured. After the silicone was formed, the clay was removed, and a silicone tube was used to connect the heart and aneurysm part. We measured the change in pressure as related to the opening time(pulse rate, Kruskal-Wallis method) and pressure before and after the stent-graft implantation(n = 5, Wilcoxon's signed ranks test). The changes in blood pressures according to pulse rate were all statistically significant(p<0.05). The systolic/diastolic pressures at the proximal aorta, the aortic aneurysm, and the distal aorta of the model were $157.80{\pm}1.92/130.20{\pm}1.92$, $159.40{\pm}1.14/134.00{\pm}2.92$, and $147.20{\pm}1.480/129.60{\pm}2.70\;mmHg$, respectively, when the pulse rate was 0.5 beat/second. The pressures changed to $161.40{\pm}1.34/90.20{\pm}1.64$, $175.00{\pm}1.58/93.00{\pm}1.58$, and $176.80{\pm}1.48/90.80{\pm}1.92\;mmHg$, respectively, when the pulse rate was 1.0 beat/second, and $159.40{\pm}1.82/127.20{\pm}1.48$, $166.60{\pm}1.67/138.00{\pm}1.87$, and $161.00{\pm}1.22/135.40{\pm}1.67\;mmHg$, respectively, when it was 1.5 beat/second. When pulse rate was set at 1.0 beat/second, the pressures were $143.60{\pm}1.67/90.20{\pm}1.64$, $147.20{\pm}1.92/84.60{\pm}1.82$, and $137.40{\pm}1.52/88.80{\pm}1.64\;mmHg$ after stent-graft implantation. The changes of pressure before and after stent-graft implantation were statistically significant(p<0.05) except the diastolic pressures at the proximal(p =1.00) and distal aorta(p=0.157). The aortic aneurysm phantoms seems to be useful for the evaluation of the efficacy of stent-graft before animal or clinical studies because of its easy reproducibility and ability to display a wide range of pressures.

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Estimating CO2 Emission Reduction of Non-capture CO2 Utilization (NCCU) Technology (NCCU(Non-Capture CO2 Utilization) 기술의 CO2 감축 잠재량 산정)

  • Lee, Ji Hyun;Lee, Dong Woog;Gyu, Jang Se;Kwak, No-Sang;Lee, In Young;Jang, Kyung Ryoung;Choi, Jong-shin;Shim, Jae-Goo
    • Korean Chemical Engineering Research
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    • 제53권5호
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    • pp.590-596
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    • 2015
  • Estimating potential of $CO_2$ emission reduction of non-capture $CO_2$ utilization (NCCU) technology was evaluated. NCCU is sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue gas. For the estimating the $CO_2$ emission reduction, process simulation using process simulator (PRO/II) based on a chemical plant which could handle $CO_2$ of 100 tons per day was performed, Also for the estimation of the indirect $CO_2$ reduction, the solvay process which is a conventional technology for the production of sodium carbonate/sodium bicarbonate, was studied. The results of the analysis showed that in case of the solvay process, overall $CO_2$ emission was estimated as 48,862 ton per year based on the energy consumption for the production of $NaHCO_3$ ($7.4GJ/tNaHCO_3$). While for the NCCU technology, the direct $CO_2$ reduction through the $CO_2$ carbonation was estimated as 36,500 ton per year and the indirect $CO_2$ reduction through the lower energy consumption was 46,885 ton per year which lead to 83,385 ton per year in total. From these results, it could be concluded that sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue was energy efficient and could be one of the promising technology for the low $CO_2$ emission technology.

The Fabrication and Characteristic for Narrow-band Pass Color-filter Deposited by Ti3O5/SiO2 Multilayer (Ti3O5/SiO2 다층박막를 이용한 협대역 칼라투과필터 제작 및 특성연구)

  • Park, Moon-Chan;Ko, Kyun-Chae;Lee, Wha-Ja
    • Journal of Korean Ophthalmic Optics Society
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    • 제16권4호
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    • pp.357-362
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    • 2011
  • Purpose: The narrow-band pass color-filters with a 500 nm central wavelength and 12 nm FWHM using $Ti_3O_5/SiO_2$ mutilayer were fabricated, and their characteristics and structures were studied. Methods: the optical constants, n and k, of the $Ti_3O_5$ and $SiO_2$ thin films were obtained from the transmittances of their thin film. The narrow-band pass color-filters were designed with these optical constants and the AR coating of the filter was also designed. $Ti_3O_5/SiO_2$ multilayer filters were made by electron beam evaporation apparatus and the transmittaces of the filters were measured by spectrophotometer. the number of layers and the thicknesses of filters were calculated from the cross section of filters by SEM image and the composition of filters was analysed by XPS analysis. Results: The optimization of AR coating for the narrow-band pass color-filter was [air$|SiO_2(90)|Ti_3O_5(36)|SiO_2(5)|Ti_3O_5(73)|SiO_2(30)|Ti_3O_5(15)|$ glass], and the optimization of filter layer for the color filter was [air$|SiO_2(192)|Ti_3O_5(64)|SiO_2(102)|Ti_3O_5(66)|SiO_2(112)|Ti_3O_5(74)|SiO_2(120)|Ti_3O_5(68)|SiO_2(123)|Ti_3O_5(80)|SiO_2(109)|Ti_3O_5(70)|SiO_2(105)|Ti_3O_5(62)|SiO_2(99)|Ti_3O_5(63)|SiO_2(98)|Ti_3O_5(51)|SiO_2(60)|Ti_3O_5(42)|SiO_2(113)|Ti_3O_5(88)|SiO_2(116)|Ti_3O_5(68)|SiO_2(89)|Ti_3O_5(49)|SiO_2(77)|Ti_3O_5(48)|SiO_2(84)|Ti_3O_5(51)|SiO_2(85)|Ti_3O_5(48)|SiO_2(59)|Ti_3O_5(34)|SiO_2(71)|Ti_3O_5(44)|SiO_2(65)|Ti_3O_5(45)|SiO_2(81)|Ti_3O_5(52)|SiO_2(88)|$ glass]. It was known that the color-filters fabricated by the simulation data were composed of 41 layers by SEM image and the top layer of filters was $SiO_2$ layer and the filters were composed of $SiO_2$/$Ti_3O_5$ multilayer by XPS analysis. It was also known that the mixed thin film of TiO2 and $Ti_3O_5$ was made during the deposition of the $Ti_3O_5$ material. Conclusions: The narrow-band pass color-filters with a 500 nm central wavelength and 12 nm FWHM using $Ti_3O_5/SiO_2$ mutilayer of 41 layer were fabricated, and it was known that the mixed form of TiO2 and $Ti_3O_5$ thin film was made during the deposition of the $Ti_3O_5$ material.

Dose verification for Gated Volumetric Modulated Arc Therapy according to Respiratory period (호흡연동 용적변조 회전방사선치료에서 호흡주기에 따른 선량전달 정확성 검증)

  • Jeon, Soo Dong;Bae, Sun Myung;Yoon, In Ha;Kang, Tae Young;Baek, Geum Mun
    • The Journal of Korean Society for Radiation Therapy
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    • 제26권1호
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    • pp.137-147
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    • 2014
  • Purpose : The purpose of this study is to verify the accuracy of dose delivery according to the patient's breathing cycle in Gated Volumetric Modulated Arc Therapy Materials and Methods : TrueBeam STxTM(Varian Medical System, Palo Alto, CA) was used in this experiment. The Computed tomography(CT) images that were acquired with RANDO Phantom(Alderson Research Laboratories Inc. Stamford. CT, USA), using Computerized treatment planning system(Eclipse 10.0, Varian, USA), were used to create VMAT plans using 10MV FFF with 1500 cGy/fx (case 1, 2, 3) and 220 cGy/fx(case 4, 5, 6) of doserate of 1200 MU/min. The regular respiratory period of 1.5, 2.5, 3.5 and 4.5 sec and the patients respiratory period of 2.2 and 3.5 sec were reproduced with the $QUASAR^{TM}$ Respiratory Motion Phantom(Modus Medical Devices Inc), and it was set up to deliver radiation at the phase mode between the ranges of 30 to 70%. The results were measured at respective respiratory conditions by a 2-Dimensional ion chamber array detector(I'mRT Matrixx, IBA Dosimetry, Germany) and a MultiCube Phantom(IBA Dosimetry, Germany), and the Gamma pass rate(3 mm, 3%) were compared by the IMRT analysis program(OmniPro I'mRT system software Version 1.7b, IBA Dosimetry, Germany) Results : The gamma pass rates of Case 1, 2, 3, 4, 5 and 6 were the results of 100.0, 97.6, 98.1, 96.3, 93.0, 94.8% at a regular respiratory period of 1.5 sec and 98.8, 99.5, 97.5, 99.5, 98.3, 99.6% at 2.5 sec, 99.6, 96.6, 97.5, 99.2, 97.8, 99.1% at 3.5 sec and 99.4, 96.3, 97.2, 99.0, 98.0, 99.3% at 4.5 sec, respectively. When a patient's respiration was reproduced, 97.7, 95.4, 96.2, 98.9, 96.2, 98.4% at average respiratory period of 2.2 sec, and 97.3, 97.5, 96.8, 100.0, 99.3, 99.8% at 3.5 sec, respectively. Conclusion : The experiment showed clinically reliable results of a Gamma pass rate of 95% or more when 2.5 sec or more of a regular breathing period and the patient's breathing were reproduced. While it showed the results of 93.0% and 94.8% at a regular breathing period of 1.5 sec of Case 5 and 6, it could be confirmed that the accurate dose delivery could be possible on the most respiratory conditions because based on the results of 100 patients's respiratory period analysis as no one sustained a respiration of 1.5 sec. But, pretreatment dose verification should be precede because we can't exclude the possibility of error occurrence due to extremely short respiratory period, also a training at the simulation and careful monitoring are necessary for a patient to maintain stable breathing. Consequently, more reliable and accurate treatments can be administered.

Impacts of Climate Change on Rice Production and Adaptation Method in Korea as Evaluated by Simulation Study (생육모의 연구에 의한 한반도에서의 기후변화에 따른 벼 생산성 및 적응기술 평가)

  • Lee, Chung-Kuen;Kim, Junwhan;Shon, Jiyoung;Yang, Woon-Ho;Yoon, Young-Hwan;Choi, Kyung-Jin;Kim, Kwang-Soo
    • Korean Journal of Agricultural and Forest Meteorology
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    • 제14권4호
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    • pp.207-221
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    • 2012
  • Air temperature in Korea has increased by $1.5^{\circ}C$ over the last 100 years, which is nearly twice the global average rate during the same period. Moreover, it is projected that such change in temperature will continue in the 21st century. The objective of this study was to evaluate the potential impacts of future climate change on the rice production and adaptation methods in Korea. Climate data for the baseline (1971~2000) and the three future climate (2011~2040, 2041~2070, and 2071~2100) at fifty six sites in South Korea under IPCC SRES A1B scenario were used as the input to the rice crop model ORYZA2000. Six experimental schemes were carried out to evaluate the combined effects of climatic warming, $CO_2$ fertilization, and cropping season on rice production. We found that the average production in 2071~2100 would decrease by 23%, 27%, and 29% for early, middle, and middle-late rice maturing type, respectively, when cropping seasons were fixed. In contrast, predicted yield reduction was ~0%, 6%, and 7%, for early, middle, and middle-late rice maturing type, respectively, when cropping seasons were changed. Analysis of variation suggested that climatic warming, $CO_2$ fertilization, cropping season, and rice maturing type contributed 60, 10, 12, and 2% of rice yield, respectively. In addition, regression analysis suggested 14~46 and 53~86% of variations in rice yield were explained by grain number and filled grain ratio, respectively, when cropping season was fixed. On the other hand, 46~78 and 22~53% of variations were explained respectively with changing cropping season. It was projected that sterility caused by high temperature would have no effect on rice yield. As a result, rice yield reduction in the future climate in Korea would resulted from low filled grain ratio due to high growing temperature during grain-filling period because the $CO_2$ fertilization was insufficient to negate the negative effect of climatic warming. However, adjusting cropping seasons to future climate change may alleviate the rice production reduction by minimizing negative effect of climatic warming without altering positive effect of $CO_2$ fertilization, which improves weather condition during the grain-filling period.

Dosimetry of the Low Fluence Fast Neutron Beams for Boron Neutron Capture Therapy (붕소-중성자 포획치료를 위한 미세 속중성자 선량 특성 연구)

  • Lee, Dong-Han;Ji, Young-Hoon;Lee, Dong-Hoon;Park, Hyun-Joo;Lee, Suk;Lee, Kyung-Hoo;Suh, So-Heigh;Kim, Mi-Sook;Cho, Chul-Koo;Yoo, Seong-Yul;Yu, Hyung-Jun;Gwak, Ho-Shin;Rhee, Chang-Hun
    • Radiation Oncology Journal
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    • 제19권1호
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    • pp.66-73
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    • 2001
  • Purpose : For the research of Boron Neutron Capture Therapy (BNCT), fast neutrons generated from the MC-50 cyclotron with maximum energy of 34.4 MeV in Korea Cancer Center Hospital were moderated by 70 cm paraffin and then the dose characteristics were investigated. Using these results, we hope to establish the protocol about dose measurement of epi-thermal neutron, to make a basis of dose characteristic of epi-thermal neutron emitted from nuclear reactor, and to find feasibility about accelerator-based BNCT. Method and Materials : For measuring the absorbed dose and dose distribution of fast neutron beams, we used Unidos 10005 (PTW, Germany) electrometer and IC-17 (Far West, USA), IC-18, ElC-1 ion chambers manufactured by A-150 plastic and used IC-l7M ion chamber manufactured by magnesium for gamma dose. There chambers were flushed with tissue equivalent gas and argon gas and then the flow rate was S co per minute. Using Monte Carlo N-Particle (MCNP) code, transport program in mixed field with neutron, photon, electron, two dimensional dose and energy fluence distribution was calculated and there results were compared with measured results. Results : The absorbed dose of fast neutron beams was $6.47\times10^{-3}$ cGy per 1 MU at the 4 cm depth of the water phantom, which is assumed to be effective depth for BNCT. The magnitude of gamma contamination intermingled with fast neutron beams was $65.2{\pm}0.9\%$ at the same depth. In the dose distribution according to the depth of water, the neutron dose decreased linearly and the gamma dose decreased exponentially as the depth was deepened. The factor expressed energy level, $D_{20}/D_{10}$, of the total dose was 0.718. Conclusion : Through the direct measurement using the two ion chambers, which is made different wall materials, and computer calculation of isodose distribution using MCNP simulation method, we have found the dose characteristics of low fluence fast neutron beams. If the power supply and the target material, which generate high voltage and current, will be developed and gamma contamination was reduced by lead or bismuth, we think, it may be possible to accelerator-based BNCT.

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Future Changes in Global Terrestrial Carbon Cycle under RCP Scenarios (RCP 시나리오에 따른 미래 전지구 육상탄소순환 변화 전망)

  • Lee, Cheol;Boo, Kyung-On;Hong, Jinkyu;Seong, Hyunmin;Heo, Tae-kyung;Seol, Kyung-Hee;Lee, Johan;Cho, ChunHo
    • Atmosphere
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    • 제24권3호
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    • pp.303-315
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    • 2014
  • Terrestrial ecosystem plays the important role as carbon sink in the global carbon cycle. Understanding of interactions of terrestrial carbon cycle with climate is important for better prediction of future climate change. In this paper, terrestrial carbon cycle is investigated by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (HadGEM2-CC) that considers vegetation dynamics and an interactive carbon cycle with climate. The simulation for future projection is based on the three (8.5/4.5/2.6) representative concentration pathways (RCPs) from 2006 to 2100 and compared with historical land carbon uptake from 1979 to 2005. Projected changes in ecological features such as production, respiration, net ecosystem exchange and climate condition show similar pattern in three RCPs, while the response amplitude in each RCPs are different. For all RCP scenarios, temperature and precipitation increase with rising of the atmospheric $CO_2$. Such climate conditions are favorable for vegetation growth and extension, causing future increase of terrestrial carbon uptakes in all RCPs. At the end of 21st century, the global average of gross and net primary productions and respiration increase in all RCPs and terrestrial ecosystem remains as carbon sink. This enhancement of land $CO_2$ uptake is attributed by the vegetated area expansion, increasing LAI, and early onset of growing season. After mid-21st century, temperature rising leads to excessive increase of soil respiration than net primary production and thus the terrestrial carbon uptake begins to fall since that time. Regionally the NEE average value of East-Asia ($90^{\circ}E-140^{\circ}E$, $20^{\circ}N{\sim}60^{\circ}N$) area is bigger than that of the same latitude band. In the end-$21^{st}$ the NEE mean values in East-Asia area are $-2.09PgC\;yr^{-1}$, $-1.12PgC\;yr^{-1}$, $-0.47PgC\;yr^{-1}$ and zonal mean NEEs of the same latitude region are $-1.12PgC\;yr^{-1}$, $-0.55PgC\;yr^{-1}$, $-0.17PgC\;yr^{-1}$ for RCP 8.5, 4.5, 2.6.