• 한국환경과학회지
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• 제26권6호
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• pp.729-739
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• 2017

The Weather Research and Forecasting (WRF) model and Vegetation Photosynthesis and Respiration Model (VPRM) were coupled to simulate atmospheric $CO_2$ concentrations. The performance of the WRF-VPRM to simulate regional scale $CO_2$ concentration was estimated over coastal basin areas. Either Hestia 2011(HST) or Vulcan 2002(VUL) anthropogenic $CO_2$ emission data were used in two numerical experiments for the study regions. Simulated meteorological variables were validated with ground and background $CO_2$ measurement data, and the results show that the model captured temporal variations of $CO_2$ concentration on a daily basis. $CO_2$ directional analysis revealed that the dominant $CO_2$ emission sources are located S and SW. The simulated Net Ecosystem Exchange (NEE) agreed relatively well with measured $CO_2$ fluxes at each vegetation class site, showing approximately 40% at max improvement at shrub areas.

• 한국환경과학회지
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• 제26권6호
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• pp.741-750
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• 2017

A model coupling a meteorological predictive model and a vegetation photosynthesis and respiration model was used to simulate $CO_2$ concentrations over coastal basin areas, and modeling results were estimated with aircraft observations during a massive sampling campaign. Along with the flight tracks, the model captured the meteorological variables of potential temperature and wind speed with mean bias results of $0.8^{\circ}C$, and 0.2 m/s, respectively. These results were statistically robust, which allowed for further estimation of the model's performance for $CO_2$ simulations. Two high-resolution emission data sets were adopted to determine $CO_2$ concentrations, and the results show that the model underestimated by 1.8 ppm and 0.9 ppm at higher altitude over the study areas during daytime and nighttime, respectively, on average. Overall, it was concluded that the model's $CO_2$ performance was fairly good at higher altitude over the study areas during the study period.

• 한국환경농학회지
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• 제13권3호
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• pp.346-358
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• 1994

In this paper, the current knowledge on the formation of acid rain and its effect on vegetation are reviewed. The pollutants which were emitted into the air are oxidized by photochemical reaction and affect the vegetation by dry and wet deposition. Acid rain at pH 4.0 affected sensitive plants and when it was below pH 3.0, visible symptoms developed in most of the crops. The acid rain treatment at pH 2.0 decreased dry weight, leaf area and chlorophyll contents in soybean but it increased rate of photosynthesis and respiration rate. Rain treatment at pH 2.8 increased ethylene production, but it’s not a suitable indicator of sensitivity to acid rain. At pH 2.0 treatment, the contents of soluble Mn and Al were increased but the cultivated soil pH at upper layer(0-5cm) was significantly decreased. The pertubation of glandular trichome which is existed along the vein was developed at all treatment except the control(pH 6.0) and non-treatment. Histological pertubation of spiked trichome and disintegration of chloroplast were developed only on the leaves of sesame treated with SAR(simulated acid rain) of pH 2.0.

• 대기
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• 제28권4호
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• pp.393-402
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• 2018

This study investigated future changes in the Arctic permafrost features and related biogeochemical alterations under global warming. The Community Land Model (CLM) with biogeochemistry (BGC) was run for the period 2005 to 2099 with projected future climate based on the Special Report on Emissions Scenarios (SRES) A2 scenario. Under global warming, over the Arctic land except for the permafrost region, the rise in soil temperature led to an increase in soil liquid and decrease in soil ice. Also, the Arctic ground obtained carbon dioxide from the atmosphere due to the increase in photosynthesis of vegetation. On the other hand, over the permafrost region, the microbial respiration was increased due to thawing permafrost, resulting in increased carbon dioxide emissions. Methane emissions associated with total water storage have increased over most of Arctic land, especially in the permafrost region. Methane releases were predicted to be greatly increased especially near the rivers and lakes associated with an increased chance of flooding. In conclusion, at the end of $21^{st}$ century, except for permafrost region, the Arctic ground is projected to be the sink of carbon dioxide, and only permafrost region the source of carbon dioxide. This study suggests that thawing permafrost can further to accelerate global warming significantly.

• 한국수자원학회논문집
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• 제56권11호
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• pp.721-728
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• 2023

농업적 가뭄이 발생하면 토양의 수분이 감소하여 식생의 광합성 및 성장을 저해한다. 광합성을 통해 대기 중의 이산화탄소가 흡수되며 산소 생산량이 증가하는데, 이러한 광합성에 부정적인 영향이 생긴다면 대기 중의 이산화탄소 농도가 증가한다. 본 연구에서는 다중분광광학센서인 MODerate resolution Imaging Spectroradiometer (MODIS) 산출물을 이용하여 토양수분, 식생 활력 및 대기 중의 이산화탄소 농도 간의 관계를 분석하였다. 토양수분의 경우, 기존의 마이크로웨이브 센서는 낮은 공간 해상도로 제공되는 특징으로 인해 소규모 연구 지역 분석에 한계가 있어서 상대적으로 고해상도인 광학센서를 이용한 토양수분 산정 방법을 적용하였다. 또한, MODIS 총일차생산량(Gross Primary Productivity, GPP) 산출물을 이용하여 식생의 호흡과의 관계식을 이용하여 이산화탄소 플럭스를 계산하였다. 원격탐사 기반의 토양수분, 식생지수와 이산화탄소 플럭스를 국내의 극한 가뭄 발생시기인 2014년과 2015년도에 대하여 지점 관측 자료인 플럭스타워 값과 비교 분석하였다. 분석한 결과 토양수분과 식생지수 사이에는 한 달의 지체시간, 식생지수와 이산화탄소 플럭스 사이에는 2주 지체시간이 발생했을 때, 상관성이 높게 나타났다.

• 한국환경복원기술학회지
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• 제22권5호
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• pp.27-43
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• 2019

This study applied the LANDIS-II model to the forest vegetation of the study area in Yeongdong-gun, Korea to identify climate effects on ecosystems of forest vegetation. The main purpose of the study is to examine the long-term changes in forest aboveground biomass(AGB) under three different climate change scenarios; The baseline climate scenario is to maintain the current climate condition; the RCP 4.5 scenario is a stabilization scenario to employ of technologies and strategies for reducing greenhouse gas emissions; the RCP 8.5 scenario is increasing greenhouse gas emissions over time representative with 936ppm of $CO_2$ concentration by 2100. The vegetation survey and tree-ring analysis were conducted to work out the initial vegetation maps and data for operation of the LANDIS model. Six types of forest vegetation communities were found including Quercus mongolica - Pinus densiflora community, Quercus mongolica community, Pinus densiflora community, Quercus variabilis-Quercus acutissima community, Larix leptolepis afforestation and Pinus koraiensis afforestation. As for changes in total AGB under three climate change scenarios, it was found that RCP 4.5 scenario featured the highest rate of increase in AGB whereas RCP 8.5 scenario yielded the lowest rate of increase. These results suggest that moderately elevated temperatures and $CO_2$ concentrations helped the biomass flourish as photosynthesis and water use efficiency increased, but huge increase in temperature ($above+4.0^{\circ}C$) has resulted in the increased respiration with increasing temperature. Consequently, Species productivity(Biomass) of trees decrease as the temperature is elevated drastically. It has been confirmed that the dominant species in all scenarios was Quercus mongolica. Like the trends shown in the changes of total AGB, it revealed the biggest increase in the AGB of Quercus mongolica under the RCP 4.5 scenario. AGB of Quercus mongolica and Quercus variabilis decreased in the RCP 4.5 and RCP 8.5 scenarios after 2050 but have much higher growth rates of the AGB starting from 2050 under the baseline scenario. Under all scenarios, the AGB of coniferous species was eventually perished in 2100. In particular they were extinguished in early stages of the RCP 4.5 and RCP 8.5 scenarios. This is because of natural selection of communities by successions and the failure to adapt to climate change. The results of the study could be expected to be effectively utilized to predict changes of the forest ecosystems due to climate change and to be used as basic data for establishing strategies for adaptation climate changes and the management plans for forest vegetation restoration in ecological restoration fields.

• 한국농림기상학회지
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• 제12권2호
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• pp.95-106
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• 2010

본 연구에서는 광릉의 활엽수림에서 관측된 생태자료들을 이용하여 CLM3.5-DGVM(Community Land Model 3.5-Dynamic Global Vegetation Model)의 탄소교환과정에 대한 모의능력을 평가하고 탄소수지를 계산하였다. 또한 식생 종의 구성과 식물계절학, 그리고 기후 변동성이 탄소수지에 미치는 영향을 조사하기 위하여 민감도 실험을 수행하였다. 모델의 식물계절학은 잎의 출현과 낙하의 시기를 잘 모의하지 못하였으며, 특히 낙엽은 관측보다 한달 이상 지연되어 생장기간을 과대모의 하였다. 모의된 최대 엽면적지수(leaf alea index, LAI)는 5.8이며 관측값(4.5)에 비해 과대모의 되었다. 과대 모의된 LAI는 광합성량과 잎의 자가영양호홉의 과대모의를 야기하였으며, 이를 통해 연간 총 일차 생산량(gross primary producing, GPP)과 생태 호흡량(ecosystem respiration, $R_e$)의 과대모의에 기여하였다. 관측과 모델간의 LAI의 차이에도 불구하고 모의된 식생 탄소 저장항의 크기는 관측 보고된 값과 유사하였다. 모델의 식물계절학함수를 사용하는 대신 관측된 PAI로부터 유도된 식물계절학을 사용하면 생육 기간이 감소함에 따라 GPP와 $R_e$의 과대 모의는 완화되었다. 하지만 관측 보고된 값과 비교할 때 여전히 큰 값을 보였다. 모의된 탄소수지는 식생 종의 구성에는 유의한 민감도를 가지지 않았다. 모델입력자료에 기후변동성의 고려 유무에 따른 평형상태의 탄소저장량의 차이는 10%이하로 낮았으며 기후변동성이 평형상태의 탄소저 장량에 미치는 영향은 유의할 수준이 아니라고 사료된다. 모델에서 모의된 GPP와 $R_e$의 1994년부터 2003년간의 연간 변동성은 연 평균 대기온도와 일사량에 의존하였다. 모델의 다른 문제점들에 관해서도 본문에서 논의되었다.

• 한국농림기상학회지
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• 제23권4호
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• pp.251-267
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• 2021

원격 탐사 기반의 식생지수들은 광합성을 조절하는 식물생리적 특성과 경험적 상관관계를 보이며, 여러공간 규모에서의 총일차생산량(GPP) 추정에 활용되고 있다. 하지만 시간 해상도가 높아질수록 식생지수를 이용한 GPP 추정의 불확실성이 커지는 한계가 존재한다. 또한 식생지수 관련 분석에 주로 사용되는 에디공분산법을 이용하여 추정한 GPP 역시 실제 측정한 순생태계교환량(NEE)을 GPP와 생태계 호흡(RE)으로 배분하는 데 사용하는 방법에 따라 추정값이 달라지는 불확실성이 존재한다. 본 연구에서는 플럭스 타워가 설치된 네 곳의 농림생태계를 대상으로 근지표에서 관측한 식생의 분광 특성을 이용한 다양한 식생지수를 계산하였고, 이를 다양한 시간 해상도에서 GPP 추정에 적용가능한 지를 분석하였다. 동시에 이를 이용하여 NEE 배분 방법의 불확실성을 평가하였다. 비교에 사용한 정규식생지수, 개량식생지수, 적외반사식생지수(NIRv)에 비해 적외반사식생지수와 광합성유효광(PAR)을 결합한 NIRvP이 식생 및 지형 조건에 의한 공간 이질성으로 인해 관측지에 따라 약간의 차이가 나타났지만, 농경지와 산림에서 모두 30분과 일 단위 시간 해상도에서 GPP와 높은 상관성(r² = 0.63, 0.68)을 보였다. 또한 기존 KoFlux 표준 NEE 배분방법에 비해 기계학습 기반의 NEE 배분 방법을 적용할 경우, 산림에서 30분 단위의 GPP와 NIRvP 사이의 상관성이 향상되었지만, 일 단위에는 그 차이가 크지 않았다. 하지만 광조건 이외에 다른 요인에 의해 광합성이 제한되는 경우 NIRvP와 GPP 간의 상관성이 떨어져 NIRvP를 이용해 실제 배분 결과를 직접 평가하긴 어려웠으며, 주로 광 조건에 의해 광합성이 제한되는 흐린 날의 경우 NEE 배분 정확도를 평가할 수 있는 가능성이 존재하였다. 그러나 높은 시간해상도의 Vis 기반의 GPP 추정이 의미를 가지려면, VIs와 GPP간의 경험적 관계를 넘어서는 시스템 사고 및 자기-조직화와 관련된 복잡계 기반의 분석 방법이 요구된다.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.210-218
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• 2018

Background: Soil respiration (Rs) is a major factor of the absorption and accumulation of carbon through photosynthesis in the ecosystem carbon cycle. This directly affects the amount of net ecosystem productivity, which affects the stability and sustainability of the ecosystem. Understanding the characteristics of Rs is indispensable to scientifically understand the carbon cycle of ecosystems. It is very important to study Rs characteristics through analysis of environmental factors closely related to Rs. Rs is affected by various environmental factors, such as temperature, precipitation, soil moisture, litter supply, organic matter content, dominant plant species, and soil disturbance. This study was conducted to analyze the effects of micro-topographical differences on Rs in forest vegetation by measuring the Rs on the ridge and southern slope sites of the broadly established Quercus mongolica forest in the central Korean area. Method: Rs, Ts, and soil moisture data were collected at the southern slope and ridge of the Q. mongolica forest in the Mt. Jeombong area in order to investigate the effects of topographical differences on Rs. Rs was collected by the closed chamber method, and data collection was performed from May 2011 to October 2013, except Winter seasons from November to April or May. For collecting the raw data of Rs in the field, acrylic collars were placed at the ridge and southern slope of the forest. The accumulated surface litter and the soil organic matter content (SOMC) were measured to a 5 cm depth. Based on these data, the Rs characteristics of the slope and ridge were analyzed. Results: Rs showed a distinct seasonal variation pattern in both the ridge and southern slope sites. In addition, Rs showed a distinct seasonal variation with high and low Ts changes. The average Rs measurements for the two sites, except for the Winter periods that were not measured, were $550.1\;mg\;CO_2m^{-2}h^{-1}$ at the ridge site and $289.4\;mg\;CO_2m^{-2}h^{-1}$ at the southern slope, a difference of 52.6%. There was no significant difference in the Rs difference between slopes except for the first half of 2013, and both sites showed a tendency to increase exponentially as Ts increased. In addition, although the correlation is low, the difference in Rs between sites tended to increase as Ts increased. SMC showed a large fluctuation at the southern slope site relative to the ridge site, as while it was very low in 2013, it was high in 2011 and 2012. The accumulated litter of the soil surface and the SOMC at the depth range of 0~5 cm were $874g\;m^{-2}$ and 23.3% at the ridge site, and $396g\;m^{-2}$ and 19.9% at the southern slope site. Conclusions: In this study, Rs was measured for the ridge and southern slope sites, which have two different results where the surface litter layer is disturbed by strong winds. The southern slope site shows that the litter layer formed in autumn due to strong winds almost disappeared, and while in the ridge site, it became thick due to the transfer of litter from the southern slope site. The mean Rs was about two times higher in the ridge site compared to that in the southern slope site. The Rs difference seems to be due to the difference in the amount of litter accumulated on the soil surface. As a result, the litter layer supplied to the soil surface is disturbed due to the micro-topographical difference, as the slope and the change of the community structure due to the plant season cause heterogeneity of the litter layer development, which in turn affects SMC and Rs. Therefore, it is necessary to introduce and understand these micro-topographical features and mechanisms when quantifying and analyzing the Rs of an ecosystem.