• Title/Summary/Keyword: 1993

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The Impact of Monsoon on Seasonal Variability of Basin Morphology and Hydrology (호수 지형 및 수리수문학적 변화에 대한 몬순 영향)

  • An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.33 no.4 s.92
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    • pp.342-349
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    • 2000
  • This paper demonstrates the influence of intensity of the monsoon on morpho-hydrological fluctuations in Taechung Reservoir during 1993${\sim}$1994. During the study, hydrological variables including rainfall, inflow, and discharge volume showed distinct contrast between 1993 and 1994. Interannaul differences in rainfall occurred during the monsoon in July${\sim}$August monsoon and influenced inflow, discharge, and water residence time (WRT). Total inflow in 1993 was four times greater than that of 1994, and summer inflow in 1993 was 8 times greater than summer 1994. Annual Mean WRT was 93.2 d in 1993 vs. 158.6 d in 1994 and the largest differences occurred between monsoons of 1993 and 1994. Morphometric variables reflected the interannual contrasts of hydrology, so that in 1993 surface area, total volume, shoreline development, and mean depth increased consistently from premonsoon to postmonsoon and over this same period in 1994 they decreased. This outcome indicates that the area of shallow littoral zones in 1993 was greater than in 1994. Also, the drainage area to surface area (D/L) at 80 m MSL was 60.7 which was much greater than values in Soyang and Andong reservoirs and natural lakes world-wide. The morpho-hydrodynamic conditions seemed to influence in-reservoir nutrient concentration which is one of the most important factors regulating the eutrophication processes. I believe, under the maximum hydrodynamic fluctuations in Korean waterbodies during the monsoon, applications of mass balance models to man-made lakes for assessments of external loading should be considered because the models can be used under the seasonally stable inflow and water residence time.

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Observational Characteristics of East Asian Monsoon during the Summers of 1993 and 1994 (1993, 1994년 여름철 동아시아몬순의 관측 특성)

  • Kim, Baek-Jo;Ryu, Chan-Su
    • Journal of the Korean earth science society
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    • v.23 no.4
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    • pp.369-379
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    • 2002
  • The characteristics of the East Asian summer monsoon circulation associated with the cool and wet summer of 1993 and the warm and dry summer of 1994 are investigated by analyzing the atmospheric circulations features in the upper and lower troposphere and by examining the global SST and associated tropical convective precipitation fields. The negative geopotential height anomalies at 500 hPa and 200 hPa in 1993 over East Asia, the central North Pacific, and the western United States were replaced by positive ones in 1994. In addition, the 200 hPa zonal wind anomaly averaged over the East Asian summer monsoon region is negatively correlated with the Korean summer temperature anomaly. The subtropical jet stream in 1993 was displaced into the central part of Korea well south of its normal position. The western Pacific subtropical high was shifted southward, and the East Asian summer rainfall and temperature was above-normal and below-normal, respectively due to the southwestward extension of a cold and dry polar airmass from the Sea of Okhotsk to the Est Sea. In contrast, the subtropical jet stream in 1994 was displaced well north of its normal position. The abrupt northward shift of the western Pacific subtropical high was accompanied with the rapid northward movement of the rain band of the East Asian summer monsoon rainfall. The anomaly patterns of the East Asia summer rainfall and temperature were opposite to those of 1993. Large sea surface temperature anomalies of opposite signs existed in the tropical Pacific with a mature El $Ni{\~{n}o$ in 1993 and a weak La $Ni{\~{n}a$ condition in 1994. The role of the anomalous convective precipitation in the western Pacific and the Indian Ocean related with the variations in the low-level cross-equatorial flow along the northwestern periphery of the Australian high and the Mascarene high is probably to influence a large-scale atmospheric circulation over the East Asia during both the years.

Influence of Low Temperature at Reproductive Stage on Rice Grain Quality (생식생장기 저온이 미질에 미치는 영향)

  • Jeong, Eung-Gi;Choi, Hae-Chune;Hong, Ha-Cheol;Moon, Huhn-Pal;Shin, Young-Beom
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.42 no.6
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    • pp.805-809
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    • 1997
  • The influence of cool temperature occurred during the booting stage in 1993 on quality of rice grain was compared with that in favorable weather of 1994. The mean and minimum air temperatures during the reproductive growth stage at the paddy field of Jinbu Substation, National Crop Experiment Station were 2.2~7.4$^{\circ}C$ and 2.0~8.9$^{\circ}C$ lower respectively in 1993 compared to those of 1994. Grain fertility and brown rice yield were 11.8% and 0.4t /ha, and 84.3% and 5.5t /ha in 1993 and 1994, respectively. There was no difference in amylose content between two years. However, protein content of brown rice in 1994 were 1.6% lower than that of 1993. There was no difference in alkali digestion value of milled rice between two years. Gel consistency of rice flour was 45mm in 1993 and 59mm in 1994. Amylogram characteristics of rice flour produced in 1993 showed lower peak hot, cool, and breakdown viscosities, and higher consistency and setback viscosities. The palatability of cooked rice by sensory panel test was considerably better in 1994 rice than in the rice of cool year.

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Incidence of Panicle Blast, Race Distribution During 1993??¡?1994 and Pathogenicity of New Races of Pyricularia grisea in Korea (벼 이삭도열병 발생정도 및 병원균 레이스의 분포 변동(1993~1994)과 새로운 레이스의 병원성)

  • 한성숙;라동수;김장규
    • Korean Journal Plant Pathology
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    • v.11 no.3
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    • pp.238-244
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    • 1995
  • Severity of panicle blast disease on the leading cultivars of rice was investigated at nine locations of Korea during summer in 1993 with frequent raining and low temperature conditions. Incidence of panicle blast was 26% on Jinmibyeo, 23% on Chuncheongbyeo and 40% on Odaebyeo. Race distribution of Pyricularia grisea was examined from 1993 to 1994. A total of 1,098 isolates of the fungus obtained from the blast nurseries and framers; fields were screened using Korean differential varieties. Twenty one races were identified in 1993 and 19 races in 1994. KI-181, KJ-103, KJ-104, KI-241 and KI-209 were identified as new races, and KJ-301 (15%), KJ-201 (13%), KJ-105 (12%) and KI-409 (12%) were major races during 1993 and 1994. Race KI-197, which has a wide spectrum of virulence on rice cultivars, was isolated in a ratio of 8.3% and evenly distributed in the whole country. Some of the major and newly identified races during 1993∼1994 were used for spray-inoculation on leading cultivars and differential varieties in a greenhouse. We found that most of the cultivars were resistant to the major races, KJ-301 and KI-409, but were very susceptible to the new races, KI-241, KI-209, KI-181 and KJ-103.

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Long-term Variations of Trophic State and Phosphorus Loading in Lake Andong, Korea (안동호의 장기간의 영양상태와 인부하량)

  • Kwon, Sang-Yong;Kim, Bom-Chul;Heo, Woo-Myung
    • Korean Journal of Ecology and Environment
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    • v.35 no.4 s.100
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    • pp.249-256
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    • 2002
  • The variation of trophic state was measured in a reservoir (Lake Andong, Korea) from 1993 to 2000. Phosphorus loading from the watershed was estimated by measuring total phosphorus concentration in the main inflowing stream (the Nakdong River). Phosphorus discharge from the pen-type fish farms was estimated from the amount of fish feed and the rate of phosphorus excretion per feed weight. The transparency in summer was about 2.0 m in 1993 and 1994, but it decreased to about 1.2 m in 1997 and 1998, and recovered to about 2.3 m in 1999 and 2000. TP increased from $11-30\;mgP/m^3$ in 1993 to $18-42\;mgP/m^3$ in 1998, but recovered to $8-13\;mgP/m^3$ in 2000, whereas TN decreased slightly from 1.81-2.96 mgN/L in 1993 to 1.17-1.80 mgN/L in 2000. TN/TP ratios decreased from 82-281 in 1993 to 21-143 in 1998, but again increased to 101-209 in 2000 due to the decrease of TP. The average chlorophyll-a concentration in growing season was in the range of $4.8-16.2\;mg/m^3$ from 1993 to 1997, but it decreased to $3.7-5.2\;mg/m^3$ after 1998. Trophic State Index had shown a gradual increase until 1996, and since then it has declined. The major cause of the trophic state recovery is thought to be the removal of fish farms in April 1998.

The Cultivation and Export of Major Medicinal Crops in Korea (최근 우리나라 주요 약용식물의 재배 및 수출에 관한 연구)

  • 박석근
    • Korean Journal of Plant Resources
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    • v.7 no.2
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    • pp.177-182
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    • 1994
  • This study was carried out to investigate about cultivation and export of major medicinal crops in Korea. The results obtained were summarized as follows'Planted area, harvested area and pro-duction were increase very much, but yield was not increased almost to 1993 from 1988. In spiteof, cultivation area was increased, export was decreased to 1993 from 1988. In cultivation area, major medicinal crops were Angelica gigas, Platycodon grandiflorum, Astragalus membranaceus, Paeonia lactiflora and Codonopsis lanceolata in 1993. In amount of export, major medicinal cropswere Ginkgo biloba, Bupleurum falcatum, Cornus officinalis, Asarum sieboldii in 1993.

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