• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.105-114
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• 2017

This study performed physical habitat simulation for fish and macroinvertebrate species in the Gongneung River. Target fishes were selected as Rhinogobius brunneus and Zacco platypus. Target macroinvertebrate species were selected as Hydropsyche kozhantschikovi and Chironomidae. Habitat suitability curves were constructed by using monitoring data from the monitoring project which is called "the survey and evaluation of aquatic ecosystem health". For calculation of CSI, weighted mean method was used. For macroinvertebrates species, the weighting factor derived from analytic hierarchy method was considered. River2D, which is capable to simulate flow in two-dimensional space, was selected for flow computation. Composite suitability index was simulated for target fish and macroinvertebrate species for discharge of drought, low, normal, and averaged-wet flow. Simulation results show that Chironomidae and Hydropsyche kozhantschikovi prefer the pool and riffle habitat, respectively. Rhinogobius brunneus and Zacco platypus show high suitability in riffle habitat.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.405-417
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• 2022

The purpose of this study was to describe the photosynthetic features of Prunus maximowiczii and Prunus serrulate Lindl. var. pubescens (Makino) Nakai in response to drought stress. Specifically, we studied the effects of drought on photosynthetic ability and photosystem II activity. Drought stress (DS) was induced by cutting the water supply for 30 days. DS decreased the moisture contents in the soil, and between the 10th and 12th days of DS, both species had 10% or less of x., After the 15th day of DS, it was less than 5%, which is a condition for disease to start. We observed a remarkable decrease of maximum photosynthesis rate starting from 10th day of DS; the light compensation point was also remarkable. Dark respiration and net apparent quantum yield decreased significantly on the 15th day of DS, and then increased on the 20th day. In addition, the stomatal transpiration rate of P. maximowiczii decreased significantly on the15th day of DS, and then increased on the 20th day. Water use efficiency increased on the 15th day of DS, and then decreased on the 20th day. The stomatal transpiration rate of P. serrulate decreased significantly on the 20th day of DS, and then increased afterward, while its water use efficiency increased on the 20th day of DS, and then decreased afterward. These results indicate that the closure of stoma prevented water loss, resulting in a temporary increase of water use efficiency. Chlorophyll fluorescence analysis detected remarkable decreases in the functional index (PI_ABS) and energy transfer efficiency in P. maximowiczii after the 15th day of DS. Meanwhile, photosystem II activity decreased in P. serrulate after 20 days of DS. In addition, Ts-Ta, PI_ABS, DI_O/RC, ET_O/RC followed similar trends as those of the soil moisture content and photosynthetic properties, indicating that they can be used as useful variables in predicting DS in trees.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.436-436
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• 2011

팔머가뭄지수(Palmer Drought Severity Index, PDSI)는 미국의 서부 캔자스와 아이오와 지역을 기반으로 Palmer(1965)에 의해 개발된 가뭄지수이다. PDSI는 가뭄을 정량적으로 표현하기 위해 제안된 최초의 포괄적인 가뭄지수라 할 수 있으며, 하나의 기상인자가 아닌 수문순환을 구성하는 여러 가지 인자들의 복합적인 작용에 의해 가뭄이 나타난다는 점에 착안하고 있다. Palmer(1965)는 캔자스와 아이오와 지역의 자료를 이용하여 산정된 수분 편차지수를 이용하여 가뭄지속기간에 대한 합을 산정하고 각각의 지속기간별로 가장 작은 값의 분포를 검토한 후 이를 기반으로 가뭄심도 분류를 위한 가뭄단계를 제시하였으며, 수분편차지수와 이전 월의 PDSI를 이용하여 분석 대상 월의 PDSI 산정을 위한 관계식을 유도하여 제시하였다. Palmer(1965)는 최대 가뭄지속기간에 대한 검토를 통해 유도된 가뭄지수 산정공식을 가뭄기 및 습윤기에 관계없이 동일하게 적용하였다. 그러나 습윤기의 경우 가뭄기간에 대해 분석된 직선과는 다른 패턴을 보일 수 있으며, 이로 인해 습윤 상태에 대해 산정된 지수는 실제 상황과 다른 결과를 나타낼 가능성이 있다. Wells 등(2004)은 이러한 점을 고려하여 가뭄기와 습윤기에 대한 지속기간별 최대 수분편차지수의 합을 도시한 결과를 나타낸 후 가뭄기와 습윤기의 특성이 다르게 나타남을 제시하였으며, 최종적으로 가뭄기와 습윤기에 대해 PDSI 산정공식의 지속기간 인자(duration factor)를 분리하여 산정할 수 있는 방법론을 제시하였다. 본 연구에서는 Wells 등(2004)에 의해 제시된 PDSI 산정공식 유도방법을 우리나라의 관측자료에 적용한 후 그 결과를 검토하였다. 그 결과 가뭄기의 경우 기존 Palmer(1965)의 결과와 매우 유사한 가뭄지수 산정 결과를 얻을 수 있었으나 습윤기에 대해 산정된 결과는 매우 다른 특성을 나타내고 있음을 확인하였다. PDSI는 가뭄 모니터링 및 관리를 위한 지표로 널리 이용되고 있으므로 적절치 못한 지수 값이 제시될 경우 효율적인 가뭄 대책 수립을 어렵게 하는 요소로 작용할 수 있다. 따라서 본 연구에서 제시된 결과는 가뭄관리 및 모니터링을 위해 PDSI를 이용함에 있어 보다 정확한 지표를 제공하기 위해 유용한 정보로 활용될 수 있을 것으로 판단된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.143-148
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• 1999

Soil moisture condition is an important limiting factor in growth and yield in rice culture. The purpose of this study was to compare the influence on the growth, yield and Quality of rice subjected to soil moisture stress (SMS) at different growth stages. Ajaponica rice cultivar, Dongjinbyeo, was cultured under flooded conditions in a plastic container filled with silty loam soil. The container was subjected to SMS until the initial wilting point (IWP) coincided with about 10% in soil moisture content and about-200 kPa in soil matric potential, and was then irrigated again, at 6 and 5 of main growth stage in 1996 and 1997, respectively. At maturity, the plant height, tiller number, leaf area and top dry weight were decreased more in SMS treatments at the early stage than the late stage. The averaged yield index of SMS to control in both years was lowest at meiosis (62.5%), which primarily resulted from lower percent ripened grain and 1,000 grain weight, and second＇ reduced the spikelet number per panicle and panicle number per hill, and followed at tillering stage (68.5%) which resulted from the lower production in tiller number and top dry matter during and after SMS treatment. The percent-age of read rice in SMS plants varied with the treatment stage as order of lower at meiosis (44.0%), heading (53.9%), panicle initiation (70.1%), tillering (72.1%), ripening (75.8%) and 5 days after transplanting (DAT) (79.0%). Protein content in brown rice was slightly larger in SMS at late growth stage than the control, while the contents of fat and ash differed very little between SMS and control. Contents of Mg and K and Mg/K in brown rice with SMS were lower at some treatment stages such as at ripening or panicle initiation.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.5-12
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• 2019

On November 15, 2017, a unpredictable liquefaction damage was occurred at the $M_L=5.4$ Pohang earthquake and after, many researches have been conducted in Korea. In Korea, where there were no cases of earthquake damage, it has been extremely neglectable in preparing earthquake risk maps and building earthquake systems that corresponded to prevention and preparation. Since it is almost impossible to observe signs and symptoms of drought, floods, and typhoons in advance, it is very effective to predict the impacts and magnitudes of seismic events. In this study, 14,040 borehole data were collected in the metropolitan area and liquefaction evaluation was performed using the amplification factor. Based on this data, liquefaction hazard maps were prepared for ground accelerations of 0.06 g, 0.14 g, 0.22 g, and 0.30 g, including 200years return period to 4,800years return period. Also, the correlation analysis between the earthquake acceleration and LPI was carried out to draw a real-time predictable liquefaction hazard map. As a result, 707 correlation equations in every cells in GIS map were proposed. Finally, the simulation for liquefaction risk mapping against artificial earthquake was performed in the metropolitan area using the proposed correlation equations.