• Title/Summary/Keyword: Meteorological element

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A Numerical Certification to Estimated Dimensions of the Observed Land-Sea Breeze Data (해륙풍관측 data의 차원추정 값에 대한 수치적 검증)

  • Lee Hwa-Woon;Kim Yoo-Keun;Lee Young-Gon
    • Journal of Environmental Science International
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    • v.8 no.6
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    • pp.661-667
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    • 1999
  • Estimating dimensions of attractors are the most basic tools to analyze properties of chaotical dynamic systems. In this paper, we estimate correlation dimensions of meteorological variables, such as wind speed (v) and temperature (T) observed in Kimhae International Airport when the land-sea breeze circulation is appeared and find low non-integer values that reflect the deterministic chaos characterizing the dynamics. We compare the results with the correlation dimensions of 2-dimensional model that is calculated by finite element method. Though the correlation dimensions of the calculated wind speed ( v) are less than those of the observed wind speed ( v), we can suggest that the land-sea breeze circulation has not a unique mechanism. The land-sea breeze phenomenon is a complicated dynamics, which is constructed with various scale motions of atmosphere. In further research, we hope to find more accurate dynamics of land-sea breeze through wide observations and using of more sophisticated prediction models.

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Numerical Analysis of Seepage Induced Earthern Slope Failures (침투가 고려된 토사사면파괴의 수치해석)

  • Seo, Young-Kyo
    • Journal of the Korean Geotechnical Society
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    • v.24 no.9
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    • pp.5-11
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    • 2008
  • Seepage induced earthern slope failures occurs in concert with meteorological events when large quantities of groundwater are channeled into slopes through infiltration. The presence of flowing groundwater in earthern slopes can induce ground failures that result in significant property damage and potential loss of life. Seepage induced earthen slope failures represent a serious problem in geotechnical engineering. This research applies existing fluid-solid numerical modeling capabilities to the study and prediction of seepage induced earthen slope failures. Study of the targeted application holds potential for much needed advances in geotechnical engineering analysis technology which could be used to design more effective engineering slope stabilization interventions.

Meteorological Element and Vegetative Structure for Sorbus commixta Hedl. Natural Populations at Ulleung Island (울릉도 마가목 천연집단의 기상인자 추정 및 식생구조)

  • 김세현;장용석;정헌관;최영철
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.5 no.3
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    • pp.158-165
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    • 2003
  • This study was conducted to reveal the role of meteorological elements on the habitat characteristics and vegetative structure for S. commixta natural populations at Ulleung Island. Potential Evapotranspiration(PET) by elevation of Ulleung Island was estimated using Thornthwaite's climatology estimating method. Also, Warm Index (WI), Coldness Index (CI) and vegetative composition by elevation were determined. The following results were obtained: The S. commixta trees wire mainly distributed from an elevation of 300 m to 900 m. The WI and CI were about 66.8∼95.0, -21.5∼-7.7, respectively. Water deficit by precipitation and Potential Evapotranspiration (PET) mainly occurred from March to October at all elevations. But wafer deficits diminished with increased elevation. The apparent species in S. commixta natural populations at Ulleung Island were: 10 tree layer species, 17 subtree layer species, and 25 species in the shrub layer. In the tree layer, S. commixta was dominant with the highest value of 46.85, then Fagus crenate 13.43, Acer mono and Tilia amurensis 12.41 and 12.03, respectively. In the subtree layer, A. mono was dominant with the highest value of 13.16, then F. crenata 12.68, Acer pseudo-sieboldianum and S. commixta 11.37 and 10.76, respectively. Dominant species and IV values in the shrub layer were Sasa borealis (22.09) and Rhododendron brachycarpum (10.51). The S. commixta natural forests were in a relatively stable rendition because of the even distribution of its various indexes: the species diversity index of Shannon, the evenness index and dominance were 0.6199∼1.1390, 0.6199∼0.8825 and 0.1852∼0.3801, respectively.

A Study on the Change of Burning Rate of Zirconium-Nickel Delay Elements Depending on the Ambient Temperature (Zr/Ni계 지연제의 주변 온도에 따른 연소속도 변화 연구)

  • Kim, Ho-Sub;Lim, Ho Young;Kang, Yo Han;Kim, Do Hyun;Lee, Geun Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.82-89
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    • 2020
  • Among the explosives in ammunition, the delay elements, which are used as a retardant, could be influenced by the ambient temperature in the Republic of Korea, where the highest and lowest average annual temperature difference is clear. On the other hand, there has been no domestic research on this. This study examined the linear burning rates of the zirconium-nickel delay elements depending on the ambient temperature in South Korea. The ambient temperature data of South Korea were obtained from the meteorological administration, which was used to set the experimental conditions. The operational time for the K414 fuze was measured by changing the ambient temperature by 10 ℃ from -40 ℃ to 50 ℃. To convert the delay time into the burning rates, the height of the delay element in the K414 fuze body was used. The results indicated that the characteristics of the burning rates for the zirconium-nickel delay element could be estimated as linear, and both the burning rates and the delay time of the zirconium-nickel delay element were 2.73mm/ms and -4.18ms, respectively. This led to an approximately 80 ms delay time difference in the environment where the highest and lowest average annual temperature difference was above 20 ℃. Therefore, the delay time reflecting the ambient temperature should be considered when the test evaluation criteria of zirconium-nickel delay elements are established.

Modeling for Predicting Yield and $\alpha$-Acid Content in Hop (Humulus lupulus L.) from Meteorological Elements II. A Model for Predicting $\alpha$-Acid Content (기상 요소에 따른 호프(Humulus lupulus L.)이 수량 및 $\alpha$-Acd 함량 예측 모형에 관한 연구 II $\alpha$-Acid 함량 예측 모형)

  • 박경열
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.33 no.4
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    • pp.323-328
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    • 1988
  • The hop alpha-acid content prediction model developed with meteorological elements in Hoeongseong was Y=28.369-0.003X$_1$+1.558X$_2$-1.953X$_3$-0.335X$_4$-0.003X$\sub$5/-0.119X$\sub$6/, with MSEp of 0.004, Rp$^2$ of 0.9987, Rap$_2$ of 0.9949 and Cp of 7.00. The total sunshine hours (X$_1$), the maximum temperature (X$_3$) and the total precipitation (X$\sub$5/) at flowering stage. the maximum temperature at flower bud differentiation stage (X$_4$) and the maximum temperature at cone ripening stage (X$\sub$6/) influenced on hop alpha .acid content as decrement weather elements. The maximum temperature at cone development stage(X$_2$) effected on ${\alpha}$-acid content as increment weather element.

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Verification of GEO-KOMPSAT-2A AMI Radiometric Calibration Parameters Using an Evaluation Tool (분석툴을 이용한 천리안2A 기상탑재체 복사 보정 파라미터 검증)

  • Jin, Kyoungwook;Park, Jin-Hyung
    • Korean Journal of Remote Sensing
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    • v.36 no.6_1
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    • pp.1323-1337
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    • 2020
  • GEO-KOMPSAT-2A AMI (Advanced Meteorological Imager) radiometric calibration evaluation is an essential element not only for functional and performance verification of the payload but for the quality of the sensor data. AMI instrument consists of six reflective channels and ten thermal infrared ones. One of the key parameters representing radiometric properties of the sensor is a SNR (Signal-to-Noise Ratio) for the reflective channels and a NEdT (Noise Equivalent delta Temperature) for the IR ones respectively. Other important radiometric calibration parameters are a dynamic range and a gain value related with the responsivity of detectors. To verify major radiometric calibration performance of AMI, an offline radiometric evaluation tool was developed separately with a real-time AMI data processing system. Using the evaluation tool, validation activities were carried out during the GEO-KOMPSAT-2A In-Orbit Test period. The results from the evaluation tool were cross checked with those of the HARRIS, which is the AMI payload vendor. AMI radiometric evaluation activities were conducted through three phases for both sides (Side 1 and Side 2) of AMI payload. Results showed that performances of the key radiometric properties were outstanding with respect to the radiometric requirements of the payload. The effectiveness of the evaluation tool was verified as well.

Optical Monitoring Strategy for Avoiding Collisions of GEO Satellites with Close Approaching IGSO Objects

  • Choi, Jin;Jo, Jung Hyun;Yim, Hong-Suh;Choi, Young-Jun;Park, Maru;Park, Sun-Youp;Bae, Young-Ho;Roh, Dong-Goo;Cho, Sungki;Park, Young-Sik;Jang, Hyun-Jung;Kim, Ji-Hye;Park, Jang-Hyun
    • Journal of Astronomy and Space Sciences
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    • v.32 no.4
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    • pp.411-417
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    • 2015
  • Several optical monitoring strategies by a ground-based telescope to protect a Geostationary Earth Orbit (GEO) satellite from collisions with close approaching objects were investigated. Geostationary Transfer Orbit (GTO) objects, Inclined GeoSynchronous Orbit (IGSO) objects, and drifted GEO objects forced by natural perturbations are hazardous to operational GEO satellites regarding issues related to close approaches. The status of these objects was analyzed on the basis of their orbital characteristics in Two-Line Element (TLE) data from the Joint Space Operation Center (JSpOC). We confirmed the conjunction probability with all catalogued objects for the domestic operational GEO satellite, Communication, Ocean and Meteorological Satellite (COMS) using the Conjunction Analysis Tools by Analytical Graphics, Inc (AGI). The longitudinal drift rates of GeoSynchronous Orbit (GSO) objects were calculated, with an analytic method and they were confirmed using the Systems Tool Kit by AGI. The required monitoring area was determined from the expected drift duration and inclination of the simulated target. The optical monitoring strategy for the target area was analyzed through the orbit determination accuracy. For this purpose, the close approach of Russian satellite Raduga 1-7 to Korean COMS in 2011 was selected.

Emission Characteristics of Elemental Constituents in Fine Particulate Matter Using a Semi-continuous Measurement System (준 실시간 측정시스템을 이용한 미세입자 원소성분 배출특성 조사)

  • Park, Seung-Shik;Ondov, John M.
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.2
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    • pp.190-201
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    • 2010
  • Fine particulate matter < $1.8{\mu}m$ was collected as a slurry using the Semicontinuous Elements in Aerosol Sampler with time resolution of 30-min between May 23 and 27, 2002 at the Sydney Supersite, Florida, USA. Concentrations of 11 elements, i.e., Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn, in the collected slurry samples were determined off-line by simultaneous multi-element graphite furnace atomic absorption spectrometry. Temporal profiles of $SO_2$ and elemental concentrations combined with meteorological parameters such as wind direction and wind speed indicate that some transient events in their concentrations are highly correlated with the periods when the plume from an animal feed supplement processing facility influenced the Sydney sampling site. The peaking concentrations of the elemental species during the transient events varied clearly as the plume intensity varied, but the relative concentrations for As, Cr, Pb, and Zn with respect to Cd showed almost consistent values. During the transient events, metal concentrations increased by factors of >10~100 due to the influence of consistent plumes from an individual stationary source. Also the multi-variate air dispersion receptor model, which was previously developed by Park et al. (2005), was applied to ambient $SO_2$ and 8 elements (Al, As, Cd, Cr, Cu, Fe, Pb, and Zn) measurements between 20:00 May 23 and 09:30 May 24 when winds blew from between 70 and $85^{\circ}$, in which animal feed processing plant is situated, to determine emission and ambient source contributions rates of $SO_2$ and elements from one animal feed processing plant. Agreement between observed and predicted $SO_2$ concentrations was excellent (R of 0.99; and their ratio, $1.09{\pm}0.35$) when one emission source was used in the model. Average ratios of observed and predicted concentrations for As, Cd, Cr, Pb, and Zn varied from $0.83{\pm}0.26$ for Pb to $1.12{\pm}0.53$ for Cd.

Space Qualification of MMICs for COMS Communications Transponder (통신해양기상위성 통신 중계기용 MMIC의 우주인증)

  • Jang, Dong-Pil;Yeom, In-Bok;O, Seung-Yeop
    • Journal of Satellite, Information and Communications
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    • v.1 no.2
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    • pp.56-62
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    • 2006
  • This paper describes the MMIC product qualification of the Ka band satellite transponder for the COMS(Communication, Ocean and Meteorological Satellite). Ka-band active equipment for the COMS communications transponder are being developed by using 12 kinds of MMICs which include low noise amplifiers, medium power amplifiers, frequency mixers, frequency multipliers, RF switch, and HEMT attenuator MMIC, Those MMICs had been fabricated at the MMIC production foundry of northrop Grumman Space Technology (Velocium) which is qualified for space application, and experienced in various space programs during past decades. For the MMIC product qualification, Visual inspection and SEM inspection had been performed, and burn-in test for 240 hours and accelerated life-test for 1000 hours had been done on test fixtures of individual MMIC products at $125^{\circ}C$. Additionally, infrared temperature scanning and finite element simulation were performed to analyze and confirm the channel temperature of semiconductor devices on several representatives of those MMIC products that os one of the most important factors in performance degradation and life reduction.

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Hydrological Review on the Fload Runoff ratio (홍수유출율에 관한 수문학적 고찰)

  • 이순혁;음성진;박명근
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.27 no.4
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    • pp.42-52
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    • 1985
  • This study was attempted to derivate empirical formulas for the runoff: ratio during ilood. season at three watersheds of Dan Yang, Chung Ju, and Yeo Ju are located at upper, middle, and lower portion of Nam Han river basin, respectively. Obtained formulas for flood runoff ratio can be applied as an element for the estimation, peak discharge for the design of various hydraulics structures which can be concidented with meteorological and topographical condition. The obtained through this study were analyzed as follows. 1.It was found that the magnitude of runoff ratio depends on the amount of rainfall for all studying basins. 2.Empirical formulas 'for the runoff' ratio were derivated as 1- 2,707 Rt0.345, 1-1.691 Rt0.242 and 1-1.807 Rt0.227 at Dan Yang, Chung Ju and Yeo Ju watershed, respectively. 3.The magnitude of runoff ratio was appeared in the order of Dan Yang, Chung Ju, and Yeo Ju are located at upper, middle and lower portion of Nam Han rivet basin, respectively. 4.It was assumed that in general the more it rains, the lesser becomes the ratio of loss rainfall. Especially, the ratio of loss rainfall for Dan Yang, upper portion of river basin was shown as the lowest among three watersheds. Besides, the magnitude of that was appeared in the order of Chung Ju and Yeo Ju watershed located at middle, and lower part of river basin, respectively. 5.Relative and standard errors of runoff ratio calculated by empirical formulas were shown to be within ten percent to the observed runoff ratio in all watersheds. 6.It is urgently essential that the effect of antecedent rainfall have an influence on the next coming flood should be studied in near future.

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