• 대기
• /
• 제24권2호
• /
• pp.159-171
• /
• 2014

This study investigated the temporal and spatial characteristics of summertime (June-August) precipitation over Korean peninsula, using Korea Meteorological Administration (KMA)is Automated Synoptic Observing System (ASOS) data for the period of 1973-2010 and Automatic Weather System (AWS) data for the period of 1998-2010.The authors looked through climatological features of the summertime precipitation, then examined the degree of locality of the precipitation, and probable precipitation amount and its return period of 100 years (i.e., an extreme precipitation event). The amount of monthly total precipitation showed increasing trends for all the summer months during the investigated 38-year period. In particular, the increasing trends were more significant for the months of July and August. The increasing trend of July was seen to be more attributable to the increase of precipitation intensity than that of frequency, while the increasing trend of August was seen to be played more importantly by the increase of the precipitation frequency. The e-folding distance, which is calculated using the correlation of the precipitation at the reference station with those at all other stations, revealed that it is August that has the highest locality of hourly precipitation, indicating higher potential of localized heavy rainfall in August compared to other summer months. More localized precipitation was observed over the western parts of the Korean peninsula where terrain is relatively smooth. Using the 38-years long series of maximum daily and hourly precipitation as input for FARD2006 (Frequency Analysis of Rainfall Data Program 2006), it was revealed that precipitation events with either 360 mm $day^{-1}$ or 80 mm $h^{-1}$ can occur with the return period of 100 years over the Korean Peninsula.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2021년도 학술발표회
• /
• pp.143-143
• /
• 2021

Climate change indicators, mainly frequent drought which has happened since the drought of 1994, 1995, and 2012 causing the devastating effect to the agricultural sector, and could be more disruptive given the context of climate change indicators by increasing the temperature and more variable and extreme precipitation. Changes in frequency, duration, and severity of droughts will have enormous impacts on agriculture production and water management. Since both the possibility of drought manifestation and substantial yield losses, we are propositioning an integrated method for evaluating past and future agriculture drought hazards that depend on models' simulations in the Hung-up watershed. to discuss the question of how climate change might influence the impact of extreme agriculture drought by assessing the potential changes in temporal trends of agriculture drought. we will calculate the temporal trends of future drought through drought indices Standardized Precipitation Evapotranspiration Index, Standardized Precipitation Index, and Palmer drought severity index by using observed data of (1991-2020) from Wonju meteorological station and projected climate change scenarios (2021-2100) of the Representative Concentration Pathways models (RCPs). expected results confirmed the frequency of extreme agricultural drought in the future projected to increase under all studied RCPs. at present 100 years drought is anticipated to happen since the result showing under RCP2.6 will occur every 24 years, RCP4.5 every 17 years, and RCPs8.5 every 7 years, and it would be double in the largest warming scenarios. On another side, the result shows unsupportable water management, could cause devastating consequences in both food production and water supply in extreme events. Because significant increases in the drought magnitude and severity like to be initiate at different time scales for each drought indicator. Based on the expected result that the evaluating the impacts of extreme agricultural droughts and recession could be used for the development of proactive drought risk management, policies for future water balance, prioritize sustainable strengthening and mitigation strategies.

• 대한공간정보학회지
• /
• 제19권1호
• /
• pp.53-61
• /
• 2011

본 연구는 U-City 논문의 연구동향을 파악하여 미래도시나 U-City 연구의 향후 과제를 도출하고 발전방향을 제시하는데 목적이 있다. 이를 위해 1990년대 중반부터 2010년까지의 국내 외 U-City 및 미래도시 관련 논문을 대상으로 메타키워드를 추출하고, 시계열적 키워드 분석을 통해 국내 외 논문의 연구경향을 비교분석 하였다. 연구 결과 국내 논문과 해외 논문 모두 기술에 관련된 연구가 많았지만 국내에서는 기술과 방법론, 서비스, 계획 및 관리 분야가 초기부터 지속적으로 연구된 반면 해외 논문은 기술 및 방법론에 대한 연구가 선행된 후 모델을 통해 도시에 적용하는 연구가 이어지는 경향을 파악할 수 있었다. 또한 국내에서는 도시재생이나 도시의 공간적 스케일을 고려한 다양한 주제별 연구가 부족한 것으로 나타났다. 따라서 향후에는 U-City가 도시에 적용될 수 있는 다양한 주제의 연구가 필요하다.

• The Korean Journal of Ecology
• /
• 제13권2호
• /
• pp.149-163
• /
• 1990

Two distinct spider communities were studied in the crowns and ground surfaces of pine plantations at Mt. Ungilsan, Kyonggi-do using pitfall traps and knock-down by spraying of an insecticide (D.D.V.P.) to sample spiders. There were 34 species of 11 families in the ground community and 41 species of 15 families in the crown community, with only 9 species being collected in both. Wandering spiders comprised 78.5% of the crown community and 90.8% of the ground community. Guild abundance and the most abundant families were distinctly different in the two habitats: agile hunters (Salticidae:32.4%) and nocturnal hunters (Clubionidae:19%) in the crown, runners (Lycocidae:32.8%) and nocturnal hunters (Gnaphosidae:31.2%) in the ground. Dominant species were Clubiona jucunda (Karsch) and Mymarachne japonica (Karsch) in the crown, while in the ground they were Pardosa laura Karsch and Gnaphosa silvicola. Species diversity(H ) had peaks in May, July and November in the ground community, while in the crown community peaks were in June and September. The seasonal trends of species diversity (H ) were due mainly to differences in the number of species and the numbers of individuals collected at each sample date rather than to differences in equitability among species. Spier guilds and dominant species have different seasonal patterns based on the temporal differences in prey availability in the two communities and the reduction of temporal overlap.

• 한국대기환경학회지
• /
• 제27권1호
• /
• pp.50-62
• /
• 2011

Temporal trends and spatial distributions of ozone concentrations in Pohang were investigated using data measured at 4 air quality monitoring stations (i.e., Daedo, Jukdo, Jangheung, and Desong) during 2002-2006. The monthly mean ozone concentrations were highest during April and June and decreased during July and August, which follows the typical trend in the Northeast Asia region. The high springtime ozone concentration might have been strongly influenced by the enhanced photochemical ozone production of accumulated precursors during the winter under increased solar radiations. In July and August, ozone levels were decreased by frequent and severe precipitation that caused lower mean monthly solar radiation and efficient wash-out of ozone precursors. This suggests that precipitation is extremely beneficial in the aspect of ozone pollution control. High ozone concentrations exceeding 80ppb dominantly occurred in May and June during the late afternoon between 16:00~17:00. Ozone concentrations were higher in Jangheung and Daesong relative to Daedo and Jukdo, whereas total oxidants $(O_3+NO_2)$ were higher in Jangheung and Daedo. In the suburban area of Daesong, ozone concentrations seem to be considerably higher than those in urban sites of Daedo and Jukdo due to lower ozone loss by NO titration with lower local NO level.

• 수산해양교육연구
• /
• 제25권5호
• /
• pp.1046-1054
• /
• 2013

Spatial and temporal variations of sea surface temperature (SST), abundances of copepods, euphausiids, amphipods, and chaetognaths were investigated in the western waters of the Korean Peninsula. Zooplankton and SST were monitored at 63 stations arrayed in six transects ($124^{\circ}00^{\prime}-126^{\circ}30^{\prime}E$, $34^{\circ}00^{\prime}-37^{\circ}00^{\prime}N$) in February, April, June, August, October, and December during 1978-2010. In general, SST increased $0.7-3.8^{\circ}C$ during the last three decades with spatio-temporal variations. SST was lowest in February and highest in August. SST was highest in the northernmost transect and declined gradually along transects to the south. The general pattern of interannual variations of SST was similar to the global pattern, which has been increasing. Trends of abundances of all zooplankton groups slightly increased interannually and peaked seasonally in June and August, except chaetognaths, which fluctuated around the long-term mean value with a seasonal peak in August and October. Abundances of zooplankton groups were highest in the northernmost transect while those of euphausiids were highest in the southern transect. We discuss the distribution patterns of SST and zooplankton groups in relation to oceanographic characteristics in the study area.

• 농촌계획
• /
• 제26권4호
• /
• pp.53-65
• /
• 2020

This study aimed to provide a basic information for managing the water quality of national and regional 1st rivers in Gyeongnam by analyzing the emerging hot spot patterns in BOD, T-P, and TOC, and by grouping the changing trends into clusters. The emerging hot spot analysis for each water quality item was implemented in ArcGIS Desktop with monthly water quality data from 96 water environmental monitoring stations in Gyeongnam, and then four patterns of water quality change were classified by the K-mean cluster analysis. As for BOD, persistent cold spot pattern covered about 42.9% of target rivers, and T-P concentration tended to be low or be getting lower at over 70% of target rivers. While, for TOC, about 70% of target rivers resulted in oscillating hot spots. In addition, the cluster analysis showed that the downstream of Nakdong river had the top priority in terms of water quality management because of the increasing concentration for all the three water quality.

• Bulletin of the Korean Chemical Society
• /
• 제18권6호
• /
• pp.588-594
• /
• 1997

Gelation time, gel structure and volatility of by-products during gelation of PZT sol-gel processing were investigated by FT-IR spectroscopy. FT-IR spectroscopic study was performed on PZT gels with the various H₂O contents (1, 2 and 3 mol) and the several types (HNO₃, NH₄OH) and amounts (0.1, 0.2 mol) of catalysts, monitoring temporal (0, 1, 3, 10 weeks, 3 months and 3 years) and thermal (100-700 ℃) changes of FT-IR spectra. The interpretation of temporal change of the spectra revealed two trends. One is under the condition of 1 mol H₂O, 1 mol H₂O+0.1 mol HNO₃, 3 mol H₂O and the other is for 1 mol H₂O+0.1 mol NH₄OH, 2 mol H₂O, 1 mol H₂O+0.2 mol HNO₃. The gel structures and the gelation times for these conditions were discussed in comparison with the reported results of SiO₂, and we suggested the reaction mechanisms for these structural characteristics. Thermal variation of FT-IR spectra was interpreted as the evolution processes of gel by investigating the evaporation of solvent and the decomposition of organic residues.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2017년도 학술발표회
• /
• pp.192-192
• /
• 2017

In this paper we showed the application of European Space Agency's C-band Sentinel-1 Synthetic Aperture Radar (SAR) imagery to identify land subsidence in a heavily groundwater pumping area. We used the repeat pass satellite interferometry method in combination with persistent scattering (PS) interferometric technique to generate and analyze twenty-eight interferograms for the period October 2014 to November 2016. The interferometry results show that land subsidence is more pronounced in the urban areas. Excessive groundwater pumping in the study area is believed to be the main reason for land subsidence. The results are compared with the subsidence rate measured by GPS as reported in other studies and with the mean change in total water storage field of GRACE solutions provided by the Jet Propulsion Laboratory (JPL), the German Research Centre for Geosciences (GFZ) and the Center for Space Research (CSR). The comparison shows persistently decreasing trends during the period of study. A strong reliance of the trend of land subsidence on the temporal decline in total water storage proposes that much of the land subsidence can be attributed to heavy pumping of the groundwater.

• Nuclear Engineering and Technology
• /
• 제55권12호
• /
• pp.4554-4560
• /
• 2023

Continuous monitoring of radioactive substances over a prolonged duration can yield crucial insights into the levels of radiation exposure through inhalation, both in the vicinity of nuclear facilities and/or general environments. In this study, we evaluated long-term measurements (2012-2022) of gross alpha-beta activities in the air in the vicinity of nuclear facilities and reference site, distribution characteristics of temporal trends and spatial fluctuations, and factors affecting radioactivity levels. The average airborne gross-α (in mBq m^-3) for onsite and off-site were 0.124 and 0.117, respectively, and the average airborne gross-β (in mBq m^-3) measurements were 1.10 and 1.04, respectively. The activity ratio (AR) of gross-α and gross-β were calculated as a ratio of 0.12. The distribution characteristics of gross-α and gross-β activities in this study area are likely influenced by the meteorological factors and variations in airborne PM concentrations rather than the operation of the nuclear facility.