산지복잡지형과 생태적 비균질성: 산지경관의 생산성과 수자원/수질에 관한 생태계 서비스 평가

강신규 ( Shin Kyu Kang ),( John Tenhunen ) 한국농림기상학회 2010 한국농림기상학회지 Vol.12 No.4

산지복잡지형은 지구표면의 약 20%를 차지하며, 절반 정도의 인류에게 맑은 물을 제공하는 지역이고, 대부분의 주요하천의 발원지로서 국가 혹은 지역 간 사회-경제적 경쟁과 정치적 논란의 대상지역이기도 하다. 산지경관생태계는 우리에게 폭넓은 생태계 생산물과 서비스(맑은 물, 에너지, 식량 및 산림자원 등)를 제공하며, 관광과 휴식활동의 대상으로 크게 부각되고 있다. 이들 지역은 특히 매우 높은 생물다양성과 육상탄소의 주요 저장원이기도 하다. TERRECO사업은 산지 복잡지형의 생태계 과정에 대한 이해를 증진하고, 생태계 서비스와 관련한 생태계 기능들을 공간적으로 평가하는 데에 중점을 둔다. 특히 정교한 평가체계를 개발함으로써 산지복잡지형에서의 기후와 토지이용변화에 따른 생태계 서비스 기능의 변화를 정량화할 것이다. 이러한 구도에서 산지복잡지형의 수문학, 수자원, 생산성, 생물다양성, 토양생지화학, 미량가스방출 및 수질 등을 복합적으로 규명하고 있다. TERRECO사업은 총 34개의 세부연구과제로 구성되었으며, 한국산지복잡지형에서의 공동연구를 통해 연구기법의 개발 및 적용을 수행 중에 있다. 세부연구과제들은 산지복잡지형의 경관비균질성에 따른 (1) 물순환과 수자원, (2) 용존유기탄소(DOC), 미세입자상 유기탄소(fPOC), 질소화합물(TN)과 인 함유 물질(TP)의 수송과 수질에 영향을 미치는 탄소와 질소 저장원, (3) 환경적 관심이 높은 미량가스(CO(2), N(2)O, CH(4))의 포집과 방출, (4) 경관의 생물다양성과 생물다양성에 기인한 생태계 서비스들, 그리고 마지막으로 (5) 농업과 산림 생산성의 차이를 조사하도록 고안하였다. 따라서 TERRECO사업은 한국 산지복잡지형의 생태계 서비스를 조절하는 원리들을 규명하고, 총 34개 세부연구과제의 결과들이 생태계 서비스의 정량적 평가체계를 수립하는 데에 기여하도록 조직화함으로써 새로운 수준의 학제간 정보교환프로그램을 개발하는 데에 기여할 것으로 기대된다. Complex terrain refers to irregular surface properties of the earth that influence gradients in climate, lateral transfer of materials, landscape distribution in soils properties, habitat selection of organisms, and via human preferences, the patterning in development of land use. Complex terrain of mountainous areas represents ca. 20% of the Earth`s terrestrial surface; and such regions provide fresh water to at least half of humankind. Most major river systems originate in such terrain, and their resources are often associated with socio-economic competition and political disputes. The goals of the TERRECO-IRTG focus on building a bridge between ecosystem understanding in complex terrain and spatial assessments of ecosystem performance with respect to derived ecosystem services. More specifically, a coordinated assessment framework will be developed from landscape to regional scale applications to quantify trade-offs and will be applied to determine how shifts in climate and land use in complex terrain influence naturally derived ecosystem services. Within the scope of TERRECO, the abiotic and biotic studies of water yield and quality, production and biodiversity, soil processing of materials and trace gas emissions in complex terrain are merged. There is a need to quantitatively understand 1) the ecosystem services derived in regions of complex terrain, 2) the process regulation occurred to maintain those services, and 3) the sensitivities defining thresholds critical in stability of these systems. The TERRECO-IRTG is dedicated to joint study of ecosystems in complex terrain from landscape to regional scales. Our objectives are to reveal the spatial patterns in driving variables of essential ecosystem processes involved in ecosystem services of complex terrain region and hence, to evaluate the resulting ecosystem services, and further to provide new tools for understanding and managing such areas.

A spatially hierarchical integration of close-range remote sensing, leaf structure and physiology assists in diagnosing spatiotemporal dimensions of field-scale ecosystem photosynthetic productivity

Xue, Wei,Ko, Jonghan,Werner, Christiane,Tenhunen, John Elsevier 2017 Agricultural and forest meteorology Vol.247 No.-

<P><B>Abstract</B></P> <P>There are great variations of inter-annual ecosystem photosynthetic productivity (GPP) in rice agricultural mosaic landscapes in Asian monsoon regions, consisting of relatively small land holdings. It is therefore of great importance to capture and interpret spatiotemporal aspects of per-field GPP. This goal, however, remains challenging partially due to absence of adequate methodology that applies ecophysiological data to broader spatial and temporal dimensions to explicitly quantify influences of environment change on per-field GPP. To accomplish the goal, field experiments were carried out at spatially adjacent flooding paddy (PD) and rainfed (RF) lowland rice (<I>Oryza sativa</I>) fields, taking year-round measurements in micrometeorological factors, leaf and canopy photosynthesis, and field reflectance with help from an unmanned aviation vehicle (UAV) system. A spatially hierarchical integration (PIXel based CANopy photosynthesis model, PIXCAN) that fuses measurements from leaf to canopy and field scales was then developed. Our results showed that the PIXCAN fusion could well capture and characterize spatial properties of per-field ecosystem GPP. Spatial variations (SV) of ecosystem carbon uptake capacity (GPP<SUB>max</SUB>) at the PD and RF fields decreased over the growing season. However, occurrence of prolonged non-precipitation period due to climate anormaly in mid-August led to severe constraints of GPP<SUB>max</SUB> and counter-seasonally strengthened SV that would decrease in the RF rice field, primarily due to drought impacts on light-harvesting efficiency and less to stomatal conductance. Collectively, we highlighted ecological implications of the integration applied at field niche in spatially hierarchical observation of ecosystem regulating/production provisions from leaf to landscape dimensions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A spatially hierarchical integration (PIXCAN) links UAV remote sensing and at-surface measurements. </LI> <LI> Spatiotemporal variations of per-field photosynthetic productivity were captured and interpreted. </LI> <LI> Occurrence of prolonged non-rainfall period led to severe constraints of GPP<SUB>max</SUB> and significantly strengthened SV. </LI> <LI> Drought-stressed ecosystem GPP<SUB>max</SUB> primarily due to constrained light-harvesting efficiency and less to stomatal conductance. </LI> <LI> Ecological implications of the integration in spatially hierarchical observation of ecosystem GPP. </LI> </UL> </P>

Potential Impacts on Climate Change on Paddy Rice Yield in Mountainous Highland Terrains

고종한,김한용,정승택,안중배,최광용,강신규,John Tenhunen 한국작물학회 2014 Journal of crop science and biotechnology Vol.17 No.3

Crop models are suitable tools to assess the potential impacts of climate change on crop productivity. While the associated assessmentreports have been focused on major rice production regions, there is little information on how climate change will impact thefuture rice crop production in mountainous highland regions. This study investigated effects of climate change on yield of paddy rice(Oryza sativa) in mountainous highland terrains of Korea using the CERES-Rice 4.0 crop model. The model was first calibrated andvalidated based on observed data and then applied to simulations for the future projections of rice yield in a typical mountainous terrainwhich borders North and South Korea, the Haean Basin in Kangwon Province, Republic of Korea. Rice yield in the highland terrainwas projected to increase by 2050 and 2100 primarily due to elevated CO2 concentration. This effect of CO2 fertilization on yield(+10.9% in 2050 and +20.0% in 2100) was also responsible for increases in water-use efficiency and nitrogen-use efficiency. Withmanagement options, such as planting date shift and increasing nitrogen application, additional yield gains were predicted in responseto the future climate in this area. We also found that improving genetic traits should be another option to get further yield increases. Allin all, climate change in mountainous highland areas should positively influence on paddy rice productivity

Environmental controls on growing-season sap flow density of Quercus serrata Thunb in a temperate deciduous forest of Korea

Laiju, Nahida,Otieno, Dennis,Jung, Eun-Young,Lee, Bo-Ra,Tenhunen, John,Lim, Jong-Hwan,Sung, Joo-Han,Kang, Sin-Kyu The Ecological Society of Korea 2012 Journal of Ecology and Environment Vol.35 No.3

Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) ($r^2$ = 0.95, P < 0.05) and sapwood area (SA) ($r^2$ = 0.98, P < 0.05). Relationships between SFD and DBH ($r^2$ = 0.25), as well as SA ($r^2$ = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.

Quantification of CO₂ fluxes in paddy rice based on the characterization and simulation of CO₂ assimilation approaches

Choi, Jinsil,Ko, Jonghan,Ng, Chi Tim,Jeong, Seungtaek,Tenhunen, John,Xue, Wei,Cho, Jaeil Elsevier 2018 Agricultural and forest meteorology Vol.249 No.-

<P><B>Abstract</B></P> <P>Quantification of the canopy photosynthesis of crops is essential for elucidation of the effects of environmental changes on CO<SUB>2</SUB> fluxes in agricultural ecosystems and crop productivity. This study was conducted to characterize the CO<SUB>2</SUB> fluxes of paddy rice (<I>Oryza sativa</I>), simulate CO<SUB>2</SUB> assimilation based on the development of a photosynthesis model, and project spatiotemporal variations in CO<SUB>2</SUB> assimilation using a crop model based on remotely sensed data in an effort to identify a link between photosynthetic productivity and accumulation of plant biomass. To perform the research practically under actual farming conditions, we investigated the effects of nitrogen (N) fertilization on canopy photosynthesis of rice grown under two levels of N application. Gross primary productivity (GPP) was calculated using net ecosystem exchange and ecosystem respiration measured in a closed-system canopy chamber. GPP was the highest in the maximum tillering stage and its minimum in the heading stage. The initial slope of the light response curve was similar during the four growth stages observed. The sensitivity of GPP to the amount of chlorophyll in the lower N treatment was higher than that in the optimum N treatment, whereas the GPP and yield in plants in the lower N treatment were lower. The photosynthesis model that was developed simulated CO<SUB>2</SUB> assimilation that had statistically acceptable agreement with the corresponding experimental measurements. In addition, projections of spatiotemporal variations in CO<SUB>2</SUB> assimilation were established using the GRAMI-rice model using remotely sensed data. These results indicated that CO<SUB>2</SUB> fluxes in paddy rice could be well quantified based on measurement and simulation projecting spatiotemporal CO<SUB>2</SUB> assimilation. As most of the information was derived from fields, it is not well organized to form one acceptable scientific streamline, efforts should be made to seek ecological implications through a fusion between at-ground measurements and remote sensing observations via model development.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Canopy-based CO<SUB>2</SUB> fluxes of rice were characterized and quantified. </LI> <LI> Lower N treatment resulted in lower GPP and crop yield. </LI> <LI> CO<SUB>2</SUB> assimilation was reproduced and spatiotemporally projected. </LI> </UL> </P>

Environmental controls on growing-season sap flow density of Quercus serrata Thunb in a temperate deciduous forest of Korea

Nahida Laiju,강신규,Dennis Otieno,정은영,이보라,John Tenhunen,임종환,성주한 한국생태학회 2012 Journal of Ecology and Environment Vol.35 No.3

Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) (r2 = 0.95, P < 0.05) and sapwood area (SA) (r2 = 0.98,P < 0.05). Relationships between SFD and DBH (r2 = 0.25), as well as SA (r2 = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.

우리나라 산간 분지 지역에서 형성되는 기온역전층의 연중 변동성

최광용(Choi, Gwangyong),이보라(Lee, Bora),강신규(Kang, Sinkyu),존 텐후넨(Tenhunen, John) 한국지역지리학회 2018 한국지역지리학회지 Vol.24 No.3

본 연구에서는 양구 해안면 펀치볼을 대상으로 연중 우리나라 산악 분지에서 나타나는 기온역전현상의 발생 빈도, 강도, 지속 시간 등의 특징과 강한 기온역전현상 발생 시 대기 상하층 종관 기후 패턴의 특징을 밝히고자 하였다. 분석결과, 연구지역의 연중 기온역전현상은 가을철 새벽에 발생률이 최대 약 46%에 달하고, 그 강도는 한겨울에 최대 약 2.6℃/100m정도로 나타났다. 이 지역의 기온역전현상에 의해 형성되는 냉기호는 겨울철 눈으로 덮인 날에 일출시간 지연 효과 및 눈 반사도 효과로 최대 약 18시간정도 지속적으로 형성되기도 한다. 상하층 종관장 분석 결과 강하고 지속 시간이 긴 기온역전현상은 겨울철에 한반도 북부 지역(120~140°E, 40~50°N)에 고기압이 자리 잡아 야간 지표 복사냉각이 잘 이루어지는 종관 상태에서 발생함을 알 수 있다. The purpose of this study is to examine the intra-annual characteristics of frequency, intensity and duration of temperature inversion phenomena occurring the in Haean basin (also called as Punch Bowl), a mountainous basin of Korea. The upper and lower synoptic climatic patterns in the occurrence of strong temperature inversion phenomena are also investigated. The incidence probability of temperature inverse layers in the study region reaches up to 46% at dawn in autumn, while its intensity maximizes up to about 2.6℃/100m at dawn in mid-winter. In the study region, the cold air drainage (cold air lake) formed by the temperature inversion phenomenon can continuously last up to about 18 hours until late afternoon on a snow-covered winter days due to snow-albedo effects as well as to the delay effect of sunrise time. The analysis of the upper and lower synoptic weather observations shows that the intense, long-lasting temperature inversion phenomena occur in winter when a high pressure system centering on the northern region (120~140°E, 40~50°N) of the Korean Peninsula is stagnant.

Evaluation of Swat for Sediment, Discharge and Crop Yield: Impact Assessment of Different Land Use Scenarios to Identify Efficient Land Use for Sediment Retention in Haean Catchment, South Korea

Ganga Ram Maharjan,Sebastian Arnhold,Bernd Huwe,John Tenhunen,Seong Joon Kim 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Up-scaling to stand transpiration of an Asian temperate mixed-deciduous forest from single tree sapflow measurements

Jung, E. Y.,Otieno, D.,Lee, B.,Lim, J. H.,Kang, S. K.,Schmidt, M. W. T.,Tenhunen, J. Springer-Verlag 2011 Plant ecology Vol.212 No.3

Quantification of Ecosystem Carbon Exchange Characteristics in a Dominant Subtropical Evergreen Forest Ecosystem

Yue-Lin Li,Guo-Yi Zhou,De-Qiang Zhang,Katherine Owen Wenigmann,Dennis Otieno,John Tenhunen,Qian-Mei Zhang,Jun-Hua Yan 한국기상학회 2012 Asia-Pacific Journal of Atmospheric Sciences Vol.48 No.1

CO2 fluxes were measured continuously for three years (2003-2005) using the eddy covariance technique for the canopy layer with a height of 27 m above the ground in a dominant subtropical evergreen forest in Dinghushan, South China. By applying gapfilling methods, we quantified the different components of the carbon fluxes (net ecosystem exchange (NEE)), gross primary production (GPP) and ecosystem respiration (Reco) in order to assess the effects of meteorological variables on these fluxes and the atmospherecanopy interactions on the forest carbon cycle. Our results showed that monthly average daily maximum net CO2 exchange of the whole ecosystem varied from −3.79 to −14.24 μmol m−2 s−1 and was linearly related to photosynthetic active radiation. The Dinghushan forest acted as a net carbon sink of −488 g C m−2 y−1, with a GPP of 1448 g Cm−2 y−1, and a Reco of 961 g C m−2 y−1.Using a carboxylase-based model, we compared the predicted fluxes of CO2 with measurements. GPP was modelled as 1443 g C m−2 y−1, and the model inversion results helped to explain ca. 90% of temporal variability of the measured ecosystem fluxes. Contribution of CO2 fluxes in the subtropical forest in the dry season (October-March) was 62.2% of the annual total from the whole forest ecosystem. On average, 43.3%of the net annual carbon sink occurred between October and December, indicating that this time period is an important stage for uptake of CO2 by the forest ecosystem from the atmosphere. Carbon uptake in the evergreen forest ecosystem is an indicator of the interaction of between the atmosphere and the canopy, especially in terms of driving climate factors such as temperature and rainfall events. We found that the Dinghushan evergreen forest is acting as a carbon sink almost year-round. The study can improve the evaluation of the net carbon uptake of tropical monsoon evergreen forest ecosystem in south China region under climate change conditions.