• Title/Summary/Keyword: climate variation

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Estimation of Climatological Standard Deviation Distribution (기후학적 평년 표준편차 분포도의 상세화)

  • Kim, Jin-Hee;Kim, Soo-ock;Kim, Dae-jun
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.19 no.3
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    • pp.93-101
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    • 2017
  • The distribution of inter-annual variation in temperature would help evaluate the likelihood of a climatic risk and assess suitable zones of crops under climate change. In this study, we evaluated two methods to estimate the standard deviation of temperature in the areas where weather information is limited. We calculated the monthly standard deviation of temperature by collecting temperature at 0600 and 1500 local standard time from 10 automated weather stations (AWS). These weather stations were installed in the range of 8 to 1,073m above sea level within a mountainous catchment for 2011-2015. The observed values were compared with estimates, which were calculated using a geospatial correction scheme to derive the site-specific temperature. Those estimates explained 88 and 86% of the temperature variations at 0600 and 1500 LST, respectively. However, it often underestimated the temperatures. In the spring and fall, it tended to had different variance (e.g., increasing or decreasing pattern) from lower to higher elevation with the observed values. A regression analysis was also conducted to quantify the relationship between the standard deviation in temperature and the topography. The regression equation explained a relatively large variation of the monthly standard deviation when lapse-rate corrected temperature, basic topographical variables (e.g., slope, and aspect) and topographical variables related to temperature (e.g., thermal belt, cold air drainage, and brightness index) were used. The coefficient of determination for the regression analysis ranged between 0.46 and 0.98. It was expected that the regression model could account for 70% of the spatial variation of the standard deviation when the monthly standard deviation was predicted by using the minimum-maximum effective range of topographical variables for the area.

Seasonal Variation of Surface Sediments and Accumulation Rate on the Intertidal Flats in Hampyong Bay, Southwestern Coast of Korea (함평만 조간대의 표층퇴적물과 집적률의 계절변화)

  • Ryu, Sang-Ock;You, Hoan-Su;Lee, Jong-Deock
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.4 no.2
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    • pp.127-135
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    • 1999
  • Grain-size distribution and accumulation rate of surface sediments on the tidal flats in Hampyong Bay, southwestern coast of Korea, were investigated in a sequential interval of 2 months for the period of 27 months (1994. 10~1996. 12). Seasonal variation of grain-size distribution is prevalent on the Shimock tidal flat in the southern side of the innerbay, rather than the Anarc tidal flat in the northern side around the baymouth. This variation, in particular, more distinctive in the areas around the both high and low tide water levels. The Shimock tidal flat shows typical seasonal variation of sedimentary processes, expected under monsoonal climate. Deposition of tine-grained sediments in summer dominates over erosion in winter, resulting in an annual accumulation rate of 3.7 mm/yr. In contrast, sedimentary processes on the Anarc tidal flat is abnormal that have experienced slight deposition of fine-grained sediments in the winter and severe erosion in the summer time, showing a negative annual accumulation rate of -49.6 mm/yr. Erosional processes in this area is interpreted due mainly to change of strength and direction of tidal currents, caused by the artificial construction of dyke for reclamation in the mid-tidal flat. As a result, It is immoderate to conclude whether sedimentary processes of Hampyong Bay is erosional or depositional at current situation. Further studies on sedimentary budget at the entrance to the bay are needed.

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Regional Crop Evaluation and Yield Forecast of Paddy Rice Based on Daily Weather Observation (일기상자료에 의한 읍면별 벼 작황진단 및 쌀 생산량 예측)

  • Cho Kyung Sook;Yun Jin-Il
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.1 no.1
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    • pp.12-19
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    • 1999
  • CERES-rice, a rice growth simulation model, was used in conjunction with daily weather data to figure out the spatial variation of the phenology and yields of paddy rice at 168 rice cultivation zone units(CZU) of Kyunggi Province in 1997. Two sets of cultivar specific coefficients, which represent early and mid-season maturing varieties, were derived from field experiments conducted at two crop experiment stations. The minimum data set to run the model for each CZU (daily maximum and minimum temperature, solar irradiance, and rainfall) was obtained by spatial averaging of existing 'Digital Map of Korean Climate'(Shin et al., 1999). Soil characteristics and management information at each CZU were available from the Rural Development Administration. According to a preliminary test using 5 to 9 years field data, trends of the phasic development(heading and physiological maturity), which were obtained from the model adjusted for these coefficients, were in good agreement with the observed data. However, the simulated inter-annual variation was somewhat greater than the reported variation. Rough rice yields of the early maturing cultivar calculated by the model were comparable with the reported data in terms of both absolute value and inter -annual variation. But those of the mid season cultivar showed overestimation. After running the simulation model runs with 1997 weather data for 168 CZU's, rough rice yields of the 168 CZU's calculated by the model were aggregated into corresponding 33 counties by acreage-weighting to facilitate direct comparison with the reported statistics from the Ministry of Agriculture and Forestry. The simulation results were good at 22 out of the 26 counties with reportedly increasing yield trend with respect to the past 9 years average.

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Characteristics and long term variation trend of water mass in the coastal part of East Sea, Korea (동해연안 수괴의 특성과 장기변동 추이)

  • Yoon, Yi-Yong;Jung, So-Jung;Yoon, Sang-Chul
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.10 no.1
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    • pp.59-65
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    • 2007
  • Rapid variation of coastal ecosystem in the East Sea of Korea, such as fishery resource variation and subtropical chang of bentic flora, accordong to the global warming are actually noticed. In this study we try to identify the characterics of water mass existing in this coastal area and to consider the variation of their physical and chemical properties using data of temperature, salinity and dissolved oxygen obtained by National Fisheries Research & Development Institute from 1960 to 2005. The temperature of all water mass rise during last 45 years; the rise of North Korea Cold Water temperature (about $2.33^{\circ}C$) is 1.5 times higher than that of Tsushima warm water (about $1.6^{\circ}C$), and the temperature rise of Tsushima Surface Water, directly affected by climate chang is $2.57^{\circ}C$, higher than the atmospheric temperature rise during same period, indicating that subtropical change makes progress more rapidly in the coastal marine ecosystem than in the land ecosystem. Otherwise, the salinity in the surface water decrease $0.29\%_{\circ}$ during last 45 years due to the rising trend of rainfall with atmospheric temperature. The dissolved oxygen concentration in the all water mass make a decreasing trend. Specially for the North Korea Cold Water, the dissolved oxygen concentration diminish 0.021 mg/l per year and the decrease in the East Sea Proper Water indicate a change of inner water circulation system.

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Infection and Mutation - On the H. P. Lovecraft's fiction and "Project LC. RC" (감염과 변이 -H. P. 러브크래프트의 소설과 『Project LC. RC』에 대하여)

  • Bok, Do-Hoon
    • Journal of Popular Narrative
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    • v.27 no.2
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    • pp.13-44
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    • 2021
  • This article describes the fear of infection through the Covid19 pandemic and the rapid phase change of human species with H. P. Lovecraft's fiction and "Project LC. RC". Pandemic and climate change, which can be called global weirding, fundamentally question the status and history of human species in the ecosystem. The horror creature and cosmological indifferentism in Lovecraft's weird fiction are contemporary in that they help shed light on today's global weirding. But Lovecraft's racism allows him to ask more fundamental questions about the logjam of his cosmic horror. "Project LC. RC" are a Korean writers's works of cultural variation that rewrites controversial racism and misogyny in Lovecraft's fiction. Such variation becomes the task of creating a mutation in Lovecraft as it becomes infected with the affection of Lovecraft's writing. This article first noted the creative power of Lovecraft's fiction that induces such a mutation. And under this premise, this article wanted to reveal the meaning of Lee Seo young, Eun rim, and Kim Bo young's recreates of Lovecraft's fiction through the analysis of images and motifs of abject, plant creature and symbiosis. Specifically, Lovecraft's creature, which evokes phallic fear, turns into an image of an abject embracing and comforting women's despair("I Want You to Stay Low"), a plant creature that provides women with refuge("Color in the Well"), and a creature of care and symbiotic life("A Sea of Plague"). This recreate/rewriting has contemporary significance in that it embodies values such as labor, care, and solidarity in their works. The conclusion noted another power of creative variation in Lovecraft's fiction, which is not reduced to recreate/rewriting.

Variations in Accumulation of Terrigenous and Biogenic Materials in the Northwest Pacific Ocean since the Last Interglacial Period

  • Hyun, Sang-Min;Taira, Asahiko;Ahagon, Naokazu;Han, Sang-Joon
    • Journal of the korean society of oceanography
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    • v.33 no.3
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    • pp.80-89
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    • 1998
  • Three cores were taken from the northwest Pacific Ocean (Shikoku Basin) to determine the accumulation rates of both biogenic and terrigeneous fractions since the last penultimate interglacial period. The sediment is characterized by large amounts of terrigenous materials with low biogenic fractions and intermittent volcanic-ash layers, suggesting a hemipelagic origin. Composition of major elements shows no significant differences among sites. Relatively small variation of TiO$_2$/Al$_2$O$_3$ ratios with respect to SiO$_2$ content is the strong evidence for the common origin of terrigenous materials. The fraction of biogenic carbonates varies from near 0% in ash layers to about 35%, with a gradual increase toward the south (St. 4 through St. 6 to St. 20). However, carbonate contents show step-wise increasing tendency from St. 4 through St. 6 to St. 20, which suggests a southward increase of carbonate production. The color reflectance indicates that the sediment of the southern sites contains relatively higher amounts of biogenic carbonates. The mass accumulation rate of terrigenous fractions during the glacial period was 2-3 times higher than that of interglacial period. This enhanced mass accumulation rate of terrigenous materials was concomitant with the high accumulation rate of biogenic fractions. The total sediment accumulation rate is considered as the most important factor controlling mass accumulation rates of the biogenic and terrigenous materials. The enhanced sediment accumulation during the glacial periods is interpreted as a consequence of climate-induced change in the supply of eolian dust from the Asian continent. Enhanced wind strength during the glacial time may have increased transportation of terrigenous materials to the ocean. Thus, variation of sediment accumulation is highly linked with climatic variations.

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RESULTS FROM ADAPTABILITY TRIAL OF RAMBOUILLET SHEEP AND THEIR CROSSBREEDING WITH KAGHANIS. EFFECTS ON EWE MATING WEIGHT, WOOL PRODUCTION, LITTER SIZE AND LAMB GROWTH

  • Nawaz, M.;Meyer, H.H.;Jadoon, J.K.;Naqvi, M.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.5 no.3
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    • pp.481-485
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    • 1992
  • In order to upgrade native sheep, Rambouillet (R) rams were mated to Kaghani (K) ewes to generate F1 ($R{\times}K$) crossbred ewes. Crossbred ewes were backcrossed to Rambouillet rams to produce B1 ($R{\times}F1$), B2 ($R{\times}B1$) and B3 ($R{\times}B2$) genotypes. Weaning weight of 2605 lambs and wool weight of 2378 mature ewe records, representing R, K, F1, B1, B2 and B3 genotypes, were analyzed to compare genetic variation among genotypes produced during upgrading process and identify genotypes of the highest performance. Performance of Rambouillets was also evaluated under semi-temperate climate. Data were adjusted for yearly variation considering Rambouillet as a control. Genotypes influenced lambs weaning weight (p<.01). B1 lambs were heaviest (18.4 kg) followed in order by B2, F1, B3, R and K lambs (18.3, 17.9, 16.9, 16.8 and 13.2 kg, respectively). The highest wool production was 2.5 kg from R ewes followed by B2 (2.3), B3 (2.3), F1 (2.0) and K (1.2) ewes (p < .01). Ewe mating weight, reproduction, growth and wool production of Rambouillets deteriorated significantly after the first decade of their importation. Compared with the first phase (1959-1971), ewe mating weight, litter size, birth weight, lamb weaning weight and wool production declined by 20, 23, 32 and 36%, respectively, in the second phase (1972-1988).

Numerical Studies on the Variation of Flow Structure Due to Sea Surface Temperature at the Lee Side of Jeju Island in the Korean Peninsula (해수면 온도변화에 따른 제주도 후면 흐름구조 변화에 관한 수치연구)

  • Lee, Soon-Hwan;Park, Gwang-Soon
    • Journal of the Korean earth science society
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    • v.27 no.1
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    • pp.61-72
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    • 2006
  • Numerical studies on the influence of interaction between atmosphere and ocean on the variation of Karman vortex at the lee side of Jeju Island were carried out. Karman vortex tends to be occurred at limited height associated with Hanla mountain. And we can find clear Karman vortex at 900 hPa height in this study. One big vortex cell occurred at lee side of Jeju Island in the begging stage of its development and the cell was divided into three small cells as time goes by. And the strength and lifetime of small vortexes depend on the distribution of SST (Sea Surface Temperature). Weak gradient of SST makes long-lasting Karman vortex but produces weak potential vorticity at lee side of Jeju-do in comparison with the vortex under strong SST gradient. Strong SST gradient also increases not only the mixing depth but also the mixing ratio at lower level of troposphere. And the increased atmospheric mixing decreases the mechanical forcing due to isolated topography. Then the strength of Karman vortex at the lee side of Jeju Island becomes weak under strong gradient of SST. Thus the evolution of Karman vortex is closely related to distribution of SST around the isolated island.

Characteristics of Seasonal Variation to Sedimentary Environment at the Estuary area of the Nakdong (낙동강 하구역의 계절적인 퇴적환경 변화특성)

  • Yoon, Eun-Chan;Lee, Jong-Sup
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.4
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    • pp.372-389
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    • 2008
  • In this study, we formed a detailed grid at the estuary area of the Nakdong and collected the surface sediments. Particle size analysis and comparison with existing data were conducted to investigate the characteristics of seasonal and long-term changes in the sediments. As a result of investigation, the distribution of the sediments showed a great change per season and was greatly influenced by the quantity of outfall discharge at the Nakdong estuary barrier and the incident wave climate. The sandy sediments showed dominant movement toward the front of Jinwoodo west of the estuary area of the Nakdong due to the influence of the ENE wave, the annually-dominant wave. And the muddy sediments showed deposition by being moved toward the deep open sea along with a current. The present conditions of the sediments at the estuary area of the Nakdong showed great differences from the results of previous studies.

Chemical and Biological Properties of Soils Converted from Paddies and Uplands to Organic Ginseng Farming System in Sangju Region

  • Lim, Jin-Soo;Park, Kee-Choon;Eo, Jinu
    • Korean Journal of Soil Science and Fertilizer
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    • v.47 no.6
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    • pp.500-505
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    • 2014
  • In recent years, organic ginseng cultivation has increased because customers prefer organic ginseng products due to the morphological quality as well as the safety such as the residuals of chemically-synthesized pesticides. Therefore, some of paddy and upland fields were converted into organic ginseng fields. Soil chemical properties, soil microflora, and soil-inhabiting animals were investigated in paddy-converted and upland organic ginseng fields in Sangju city, Korea. There was few difference in the soil chemical properties, and the soil nutrient concentrations, such as nitrate-N, Av. $P_2O_5$ between the two field types, and exchangeable cations such as K and Ca were within the ranges which are recommended by the standard ginseng-farming manual. Changes in microflora were also assessed by analyzing phospholipid fatty acid composition. Overall, indicators of microbial groups were greater in the upland field than in the paddy-converted soil, but they were not significantly different. In addition, there was no significant change in the abundance of nematodes, collembolans, and mites between the two field types probably because of the high variation within the field types. In this study, it was suggested that soil chemical and biological properties for organic ginseng cultivation were greatly influenced by the variation of topography and soil management practices rather than field types. Further study may be needed to investigate the influence of these factors on soil chemical and biological properties in organic ginseng soils.