• Journal of Forest and Environmental Science
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• 제28권2호
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• pp.118-136
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• 2012

Investigation of flora was performed from March to October of 2008 as Eastern and Western coastal districts located in the same latitude ($36^{\circ}47^{\prime}-37^{\circ}48^{\prime}$), in order to apply this to basic data for effective protection and management of coastal forests also for insurance of biodiversity in coastal forests. As a result of the investigation of floras, both coastal forests recorded product-plants as follows: 98 families, 262 genera, 370 species, 46 varieties, 4 forms, 1 hybrid, 421 taxa in total. The Eastern coastal forests had 85 families, 188 genus, 248 species, 32 varieties, 3 forms, 1 hybrid, 285 taxa in total, whereas Western coastal forest had 96 families, 227 genus, 306 species, 39 varieties, 2 forms, 1 hybrid, 348 taxa in total. Among them, seashore plants accounted for 10.2% of total plants appeared in both coastal, and they are 26 families, 38 genus, 40 species, 3 hybrids and 43 taxa in total. There are special Korea plants in both coastal; 9 families, 9 genus, 8 species, 1 varieties, 1 hybrid, 10 taxa in total. There are rare plants in both coastal; 8 families, 8 genus, 7 species, 1 varieties, 8 taxa in total. Naturalized plants are also existed; 11 families, 24 species, 1 variety, 30 taxa in total.

• 대기
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• 제22권2호
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• pp.267-277
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• 2012

The objectives of this study are to develop a real-time drought monitoring and prediction system on the East Asia domain and to evaluate the performance of the system by using past historical drought records. The system is mainly composed of two parts: drought monitoring for providing current drought indices with meteorological and hydrological conditions; drought outlooks for suggesting future drought indices and future hydrometeorological conditions. Both parts represent the drought conditions on the East Asia domain (latitude $21.15{\sim}50.15^{\circ}$, longitude $104.40{\sim}149.65^{\circ}$), Korea domain (latitude $30.40{\sim}43.15^{\circ}$, longitude $118.65{\sim}135.65^{\circ}$) and South Korea domain (latitude $30.40{\sim}43.15^{\circ}$, longitude $118.65{\sim}135.65^{\circ}$), respectively. The observed meteorological data from ASOS (Automated Surface Observing System) and AWS (Automatic Weather System) of KMA (Korean Meteorological Administration) and model-driven hydrological data from LSM (Land Surface model) are used for the real-time drought monitoring, while the monthly and seasonal weather forecast information from UM (Unified Model) of KMA are utilized for drought outlooks. For the evaluation of the system, past historical drought records occurred in Korea are surveyed and are compared with the application results of the system. The results demonstrated that the selected drought indices such as KMA drought index, SPI (3), SPI (6), PDSI, SRI and SSI are reasonable, especially, the performance of SRI and SSI provides higher accuracy that the others.

• 대기
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• 제23권4호
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• pp.377-387
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• 2013

Projections of changes in the low latitude atmospheric circulation under global warming are investigated using the results of the CMIP5 ensemble mean. For this purpose, 30-yr periods for the present day (1971~2000) and the end of the $21^{st}$ century (2071~2100) according to the RCP emission scenarios are compared. The wintertime subtropical jet is projected to strengthen on the upper side of the jet due to increase in meridional temperature gradient induced by warming in the tropical upper-troposphere and cooling in the stratosphere except for the RCP2.6. It is also found that a strengthening of the upper side of the wintertime subtropical jet in the RCP2.6 due to tropical upper-tropospheric warmings. Model-based projection shows a weakening of the mean intensity of the Hadley cell, an upward shift of cell, and poleward shift of the Hadley circulation for the winter cell in both hemispheres. A weakening of the Walker circulation, which is one of the most robust atmospheric responses to global warming, is also projected. These results are consistent with findings in the previous studies based on CMIP3 data sets. A weakening of the Walker circulation is accompanied with decrease (increase) in precipitation over the Indo-Pacific warm pool region (the equatorial central and east Pacific). In addition, model simulation shows a decrease in precipitation over subtropical regions where the descending branch of the winter Hadley cell in both hemispheres is strengthened.

• Journal of Biosystems Engineering
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• 제25권6호
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• pp.497-502
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• 2000

For the analysis of geothermal energy utilization in agriculture the relations between soil temperature and geographical variables such as latitude longitude and sea level in Korea were analyzed and the regression equations were suggested among them. The measured soil temperature data for four years in eighteen cities were used to get the soil temperature fitting equation depending on the soil depth and the time of year in each city. The mean correlation coefficient for those data fitting was 0.980. the correlation coefficient of regression analysis for the mean soil temperature($T_{m}$) on the geographical variables such as latitude longitude and height above sea level was 0.958 and those for soil surface temperature amplitude(Tss) and phase constant(tp) were 0.889, 0.835, respectively. The relation between the apparent thermal diffusivity of the soil and the three geographical variables was not significant. The regression equations for the mean soil temperature($T_{m}$) soil surface temperature amplitude(Tss) and phase constant(tp) adopting latitude($X_{1}$) longitude($X_2$) height above sea level($X_3$) were as follows : $T_{m}$=50.049 - $0.849X_1$-$0.03131X_2$-$0.00622X_3$Tss=-6.970 +$0.584X_1$+$0.00530X_2$-$0.00214X_3$tp=70.353 - $1.404X_1$+ $0.02098X_2$+ $0.00312X_3$

• Journal of Astronomy and Space Sciences
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• 제30권1호
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• pp.25-32
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• 2013

We statistically investigated the properties of low-latitude Pi2 pulsations using Bohyun (BOH, Mlat = $29.8^{\circ}$, L = 1.35) ground magnetometer data in 2008. For this 1-year interval, 582 Pi2 events were identified when BOH was in the nightside from 1800 to 0600 local times. We found the following Pi2 characteristics. (1) The occurrence distribution of Pi2s is relatively constant in local times. (2) The Pi2 frequency varies in local times. That is, Pi2 pulsations in postmidnight sector had higher frequency than in premidnight sector. (3) Pi2 power in premidnight sector is stronger than in postmidnight sector. (4) Pi2 frequency has positive correlation with solar wind speed and AE index. (5) Pi2 power has not a clear correlation with solar wind parameters. This indicates that Pi2 power is not controlled by external sources. (6) It is found that the most probable-time between Pi2 onsets is ${\Delta}t$ ~ 37.5 min: This is interpreted to be the period between Pi2 pulsations when they occur cyclically. We suggest that ${\Delta}t$ ~ 37.5 min is the occurrence rate of reconnection of open field lines in the tail lobe.

• 천문학회보
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• 제37권2호
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• pp.121.1-121.1
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• 2012

It has been suggested that oscillatory earthward bursty bulk flows (BBFs) in the magnetotail are driving Pi2 oscillations on the ground. However, only a few studies examined the BBF-driven Pi2 model. The goal of this study is to establish the relation between BBFs and Pi2s. In order to examine BBF-drive model, we will conduct the timing analysis between BBFs and Pi2s for the intervals during which both Pi2 and BBF are present. In our study BBFs are identified with earthward flow speeds up to 200 km/s from THEMIS probes with a geocentric distance between 7 and 12 RE in the nightside magnetosphere for the interval from January 2008 to March 2008. Pi2 pulsations are identified at three low/mid-latitude ground stations having different local times; Bohyun (L = 1.35, LT ~ UT +9 hr), Hermanus (L = 1.83, LT ~ UT +2 hr) and Carson city (L = 2.00, LT ~ UT -2 hr). It is found that ~28% of BBFs have onset timing nearly identical to Pi2 onset. To investigate whether there is high similarity in the waveform between BBF and Pi2 oscillations, the coherence analysis is applied to the time series of BBF and Pi2 events. We found that there is no high coherence between BBF and Pi2 oscillations. Thus our observations suggest that low-latitude Pi2 oscillations are not directly driven by earthward flow bursts.

• Wind and Structures
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• 제16권6호
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• pp.579-601
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• 2013

Interference effects are of considerable concern for group hyperboloidal cooling towers, but evaluation methods and results are different from each other because of the insufficient understanding on the structure behavior. Therefore, the mechanical performance of hyperboloidal cooling tower shell under wind loads was illustrated according to some basic properties drawn from horizontal rings and cantilever beams. The hyperboloidal cooling tower shell can be regarded as the coupling of horizontal rings and meridian cantilever beams, and this perception is beneficial for understanding the mechanical performance under wind loads. Afterwards, the mean external latitude wind pressure distribution, CP(${\theta}$), was artificially adjusted to pursue the relationship between different CP(${\theta}$) and wind-induced responses. It was found that the maximum responses in hyperboloidal cooling tower shell are primarily dominated by the non-uniformity of CP(${\theta}$) but not the local pressure amplitude CP or overall resistance/drag coefficient CD. In all the internal forces, the maximum amplitude of meridian axial tension shows remarkable sensitivity to the variation of CP(${\theta}$) and it's also the controlling force in structure design, so it was selected as an indicator to evaluate the influence of CP(${\theta}$) on responses. Based on its sensitivity to different adjustment parameters of CP(${\theta}$), an comprehensive response influence factor, RIF, was deduced to assess the meridian axial tension for arbitrary CP(${\theta}$).

• 전기전자학회논문지
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• 제24권4호
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• pp.1176-1179
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• 2020

선박의 이동 경로를 예측하는 기존의 방법들은 일반적으로 위도와 경도를 직접 예측한다. 하지만, 위도와 경도를 직접 예측할 경우, 예측 모델이 출력 가능한 범위가 상당히 넓어서 예측 오차가 매우 크게 발생할 수 있다. 또한, 순환 신경망 모델 기반의 예측에서는 이전 예측 위치도 다음 위치를 예측하기 위해 사용되기 때문에 오차가 누적되는 현상도 쉽게 발생할 수 있다. 이에 따라, 제안하는 방법에서는 위도와 경도를 직접 예측하지 않고, 선박의 가속도를 예측하여, 향후 속도와 방향을 결정하고, 그 결과로 위도와 경도가 예측되는 방법을 제안한다. 실험 결과에서는 같은 순환 신경망 모델을 사용했을 때, 제안하는 방법이 기존의 직접적으로 위도와 경도를 예측하는 방법에 비해 더 적은 오차를 발생시킴을 보인다.

• Journal of Ecology and Environment
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• 제45권1호
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• pp.17-23
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• 2021

Background: Montane wetlands are unique wetland ecosystems with distinct physicochemical characteristics, and Molinia japonica often makes dominant communities in montane wetlands in South Korea. In order to figure out the environmental characteristics of M. japonica habitats and the major factors for the growth of M. japonica, field surveys were conducted in five wetlands from September to October 2019. Also, soil was collected at every quadrats installed in surveyed wetlands to analyze the physicochemical features. Results: The relative coverage of M. japonica was higher in low latitude wetlands than in high latitude. Redundancy analysis showed that soil water content had the strongest effect on the growth of M. japonica (F = 23.0, p < 0.001). Soil water content, loss on ignition, and relative light intensity showed a high correlation with the density (R = 0.568, 0.550, 0.547, respectively, p < 0.01) and the coverage of M. japonica (R = 0.495, 0.385, 0.514, respectively, p < 0.01). Soil water content, loss on ignition, and pH were highly correlated with each other. Conclusions: Molinia japonica lives in acidic wetlands at high altitude in temperate zone of low latitude, with peat layer placed on the floor. Also, M. japonica prefers open spaces to secure enough light for photosynthesis. High shoot production of M. japonica resulted in adding new peat material in every year, and this layer enforces the environmental characteristics of M. japonica habitats. This study may provide insights for further understanding of the method how wetlands maintain acidic condition by itself in montane wetlands in temperate zone.

• Journal of the Korean Wood Science and Technology
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• 제51권4호
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• pp.295-308
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• 2023

This study applied a real-time IoT (Internet of Things) environmental monitoring system to wooden cultural heritages (WCHs) located in suburbs and forests in Korea. It automated the graphs of seasonal Temperature (T) and relative humidity (RH) changes inside the heritage structures and seasonal Performance Index (PI) values. While utilizing line graphs of the existing T and RH change trends and a bar graph expressing the PI values, this study examined the current status of the conservation environment inside the WCHs throughout the year and its diagnosis. Consequently, at higher latitudes, the organic cultural heritage repeatedly experienced large T fluctuations, and the risk of physical and chemical degradation of the materials was greater. However, the RH showed significant seasonal differences, even within the same latitude, indicating that the impact of latitude was not significant. Therefore, the staff in charge must manage RH by considering the surrounding environmental conditions and adjusting the internal environment of the structures. The PI values for the year-round T and RH inside the heritages were confirmed to only be a maximum of approximately 60% of the environmental suitability for conservation throughout the year, depending on the season. The relationship between the germination and growth potential period of xerophilic fungi and the monthly internal temperature and humidity in five heritages located at different latitudes was analyzed. As a result, we could thus determine that four particular months of the year (June-September) represent the periods with the highest risk of damage from xerophilic fungi in the country, regardless of latitude.