• Title/Summary/Keyword: Regional prediction

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Verification of the Wind-driven Transport in the North Pacific Subtropical Gyre using Gridded Wind-Stress Products Constructed by Scatterometer Data

  • Aoki, Kunihiro;Kutsuwada, Kunio
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.418-421
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    • 2007
  • Using gridded wind-stress products constructed by satellite scatterometers (ERS-1, 2 and QSCAT) data and those by numerical weather prediction(NWP) model(NCEP-reanalysis), we estimate wind-driven transports of the North Pacific subtropical gyre, and compare them in the central portion of the gyre (around 300 N) with geostrophic transports calculated from historical hydrographic data (World Ocean Database 2005). Even if there are some discrepancies between the wind-driven transports by the QSCAT and NCEP products, they are both in good agreement with the geostrophic transports within reasonable errors, except for the regional difference in the eastern part of the zone. The difference in the eastern part is characterized by an anticyclonic deviation of the geostrophic transport resulting from an anti-cyclonic anomalous flow in the surface layer, suggesting that it is related to the Eastern Gyral produced by the thermohaline process associated with the formation of the Eastern Subtropical Mode Water. We also examine the consistency of the Sverdrup transports estimated from these products by comparing them with the transports of the western boundary current, namely the Kuroshio regions, in previous studies. The net southward transport, based on the sum of the Sverdrup transports by QSCAT and NCEP products and the thermohaline transport, agrees well with the net northward transport of the western boundary current, namely the Kuroshio transport. From these results, it is concluded that the Sverdrup balance can hold in the North Pacific subtropical gyre.

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Analysis of the Numerical Simulation Accuracy in the CFRP-Al Alloy SPR Joint Process According to the CFRP Modeling Method (CFRP 모델링 기법에 따른 CFRP-Al합금 SPR 접합공정의 수치해석 정확도 분석)

  • Kim, S.H.;Park, N.;Song, J.H.;Noh, W.;Park, K.Y.;Bae, G.
    • Transactions of Materials Processing
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    • v.29 no.5
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    • pp.265-271
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    • 2020
  • The purpose of this paper is to analyze the numerical simulation accuracy according to the CFRP modeling method in the CFRP-Al alloy SPR (Self-Piercing Rivet) joint process. The mechanical properties of the CFRP, aluminum sheet are precisely obtained from the tensile test according to the loading direction. Additionally, the hardening curve of rivet was calculated from the inverse analysis of the machined rivet-ring compression test. For the CFRP-Al alloy SPR simulation, two kinds of the CFRP modeling methods were established based on the continuum and layer-by-layer approaches. The simulation results showed that the CFRP layer-by-layer modeling method can provide more reliable prediction shape of the fractured sheets and deformed rivet. This simulation technique can be used in evaluating the CFRP-Metal SPR performance and designing the SPR process conditions.

The Influence of Aerosol Source Region on Size-resolved Hygroscopicity During the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) Campaign

  • Lee, Yong-Seob
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.E1
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    • pp.9-18
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    • 2006
  • Aerosol hygroscopic properties were measured by a tandem differential mobility analyzer (TDMA) system during the Aerosol Characterization Experiment (ACE)-Asia campaign from 31 March to 1 May 2001. Two high flow differential mobility analyzers (DMAs) were used to maximize the count rate on board the Center for Interdisciplinary Remotely Piloted Aircraft (CIRPAS) Twin Otter aircraft. Hygroscopic growth factor distributions of particles having initial dry nanoparticle diameters of 0.040, 0.059, 0.086, 0.126, 0.186, 0.273, 0.400, and 0.586μm were measured during 19 research flights. Data collected during 12 of those flights were used to investigate aerosol mixing state and the influence of aerosol source region on size-resolved hygroscopicity. The uniformity in size-resolved hygroscopicity was quantified to facilitate comparison between measurements made in different air masses. Hygroscopic growth factors are strongly dependent on source region and sizes. Mean hygroscopic growth factors were observed to be greatest when the air mass origin was from the south. The mean growth factors for continental sources decreased with initial size from 1.47 to 1.27 for 0.040μmand0.586μm, but increased with initial size from 1.44 to 1.8 for 0.040μmand0.400μm dry diameters for marine sources.

A Numerical Experiments on the Atmospheric Circulation over a Complex Terrain around Coastal Area. Part II : (연안부근 복잡지형의 대기유동장 수치실험 II -부산광역지역에 대한 국지순환모형의 적용-)

  • 김유근
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.2
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    • pp.151-158
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    • 2000
  • Since Pusan metropolitanarea where is composed complex terrain is connected to sea the sea-land breeze circulation and the mountain-valley circulation are apt to form A regional scale circulation system is formed at a region which has complex terrain because of curves of its and affect to the dispersion and advection of air pollutants. LCM Local Circulation Model which a propriety was verified described that sea breeze and valley wind at the daytime and land breeze and mountain wind at the nighttime were well devellped over the Pusan metropolital area. Next for the investigation of accuracy of simulated results an observed value at Kae-Kum and Su-Young on the pusan metropolitan area were compared with it at those points. From the comparison of the temperature and horizontal velocity between the results of LCM and an observed values they have a similar trend of a diurnal variation. For the prediction of dispersion and transportation of air pollutants the wind field should be calculated with high accuracy. A numerical simulation using LCM can provide more accuracy results around Pusan metropolitan area.

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An Investigation of Synoptic Condition for Clear-Air Turbulence (CAT) Events Occurred over South Korea (한국에서 발생한 청천난류 사례에서 나타나는 종관규모 대기상태에 대한 연구)

  • Min, Jae-Sik;Chun, Hye-Yeong;Kim, Jung-Hoon
    • Atmosphere
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    • v.21 no.1
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    • pp.69-83
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    • 2011
  • The synoptic condition of clear-air turbulence (CAT) events occurred over South Korea is investigated, using the Regional Data Assimilation and Prediction System (RDAPS) data obtained from the Korea Meteorological Agency (KMA) and pilot reports (PIREPs) collected by Korea Aviation Meteorological Agency (KAMA) from 1 Dec. 2003 to 30 Nov. 2008. Throughout the years, strong subtropical jet stream exists over the South Korea, and the CAT events frequently occur in the upper-level frontal zone and subtropical jet stream regions where strong vertical wind shears locate. The probability of the moderate or greater (MOG)-level turbulence occurrence is higher in wintertime than in summertime, and high probability region is shifted northward across the jet stream in wintertime. We categorize the CAT events into three types according to their generation mechanisms: i) upper-level front and jet stream, ii) anticyclonically sheared and curved flows, and iii) breaking of mountain waves. Among 240 MOG-level CAT events reported during 2003-2008, 103 cases are related to jet stream while 73 cases and 25 cases are related to the anticyclonic shear flow and breaking of mountain wave, respectively.

Rainfall-intensity distribution for an analysis of the effects of rain attenuation (강우감쇠의 영향 분석을 위한 국내 각 지역의 강우강도 분포)

  • 이형수;신철호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.4
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    • pp.1006-1015
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    • 1998
  • In general, attenuation at frequencies over 20GHz is mainly due to absorption by satmospheric gases, rain, and snow. Among this factors rain become an important limiting factor. Rain attenuation is highly influenced by rainfall-intensity and it varies over time and space. Thus it is requeired to obtain spatial and temporal data of rainfall-intensity for precise prediction of rainfall attenuation. In this paper, rainfall intensity of thiry-two measurement sites in South Korea excluding JeiJdo Islands over recent ten years is obtained and the regional relation between rainfall-intensity and percent of time is analyzed. Also we present the new method about rainfall-intensity cumulative distribution.

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Safety Monitoring Sensor for Underground Subsidence Risk Assessment Surrounding Water Pipeline (상수도관로의 주변 지반침하 위험도 평가를 위한 안전감시 센서)

  • Kwak, Pill-Jae;Park, Sang-Hyuk;Choi, Chang-Ho;Lee, Hyun-Dong
    • Journal of Sensor Science and Technology
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    • v.24 no.5
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    • pp.306-310
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    • 2015
  • IoT(Internet of Things) based underground risk assessment system surrounding water pipeline enables an advanced monitoring and prediction for unexpected underground hazards such as abrupt road-side subsidence and urban sinkholes due to a leak in water pipeline. For the development of successful assessment technology, the PSU(Water Pipeline Safety Unit) which detects the leakage and movement of water pipes. Then, the IoT-based underground risk assessment system surrounding water pipeline will be proposed. The system consists of early detection tools for underground events and correspondence services, by analyzing leakage and movement data collected from PSU. These methods must be continuous and reliable, and cover certain block area ranging a few kilometers, for properly applying to regional water supply changes.

Estimation of Surface Wind Speed on the Strong Wind Damage by Typhoon (태풍으로 인한 강풍 피해 추정을 위한 지상풍 산정 연구(Ⅰ))

  • Park, Jong-Kil;Jung, Woo-Sik;Choi, Hyo-Jin
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.85-88
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    • 2008
  • Damage from typhoon disaster can be mitigated by grasping and dealing with the damage promptly for the regions in typhoon track. What is this work, a technique to analyzed dangerousness of typhoon should be presupposed. This study estimated 10m level wind speed using 700hPa wind by typhoon, referring to GPS dropwindsonde study of Franklin(2003). For 700hPa wind, 30km resolution data of Regional Data Assimilation Prediction System(RDAPS) were used. For roughness length in estimating wind of 10m level, landuse data of USGS are employed. For 10m level wind speed of Typhoon Rusa in 2002, we sampled AWS point of 7.430km distant from typhoon center and compare them with observational data. The results show that the 10m level wind speed is the estimation of maximum wind speed which can appear in surface by typhoon and it cannot be compared with general hourly observational data. Wind load on domestic buildings relies on probability distributions of extreme wind speed. Hence, calculated 10m level wind speed is useful for estimating the damage structure from typhoon.

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Prediction of Long-term Runoff for Hapcheon Dam Watershed through Multi-Artificial Neural Network Downscaling of KMA's RCM (기상청 RCM전망의 다지점 인공신경망 상세화를 통한 합천댐 유역의 장기유출 전망)

  • Kang, Boo-Sik;Moon, Su-Jin;Kim, Jung-Joong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.948-948
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    • 2012
  • 합천댐유역에 대한 기후변화에 따른 수문학적 영향을 정량적으로 분석하기 위해, 기상청에서 제공하는 공간해상도 27km의 MM5 RCM(Regional Climate Model)을 사용하였다. RCM의 기상변수들은 공간적 스케일의 상이성과 RCM 기후변수들의 불확실성 때문에 유출모형인 SWAT의 입력자료로 사용하기에는 어려움이 있다. 특히, RCM 변수들 중 강수량의 경우 한반도 지역의 6월과 10월 사이에 연강수량의 67%이상이 집중되는 계절성을 반영하지 못하고 있는 실정이기 때문에 국내 유역의 유출량 산정에 사용하기 위해서는 지역적 상세화(Downscaling)가 필요하다. 본 연구에서는 RCM 기후변수에 내포된 공간적 스케일의 상이성과 불확실성을 최소화하기 위해 강우관측소 지점을 단위로 한 다지점 인공신경망 기법을 적용하여 강수량, 습도, 최고기온 및 최저기온에 대한 상세화를 실시하였다. 강수의 경우 여름철 태풍사상을 모의하기 위한 Stochastic Typhoon Simulation기법과 Baseline(1991~2010)과 Projection(2011~2100) 사이의 강수량 보정을 위한 Dynamic Quantile Mapping 기법을 적용하여, 강수량의 불확실성을 최소화 하고자 하였다. 상세화된 기후자료를 이용한 SWAT 모형의 일(Daily) 단위 강우-유출 모의결과를 2011~2040년, 2041~2070년, 2071~2100년으로 구분하여 추세분석을 실시하였다.

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A Study on the Appropriate Size of Stores and Countermeasures in Decline Commercial Area in the Original Downtown

  • Ryu, Tae-Chang
    • Journal of Distribution Science
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    • v.19 no.11
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    • pp.49-57
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    • 2021
  • Purpose: In this study, we try to figure out the appropriate size of commercial districts in the original downtown area through empirical studies targeting the Jinju Central Commercial Area in Gyeongnam and Cheonan Station in Chungnam, which are trying to regenerate a specific space that has been lost through government projects. Research design, data and methodology: The current status and characteristics of the shopping district were examined through on-site surveys of the central business district of Jinju, Gyeongnam Province, and Cheonan Station, Chungnam Province, and the size of the empty stores was determined. In addition, the standard median income was used as the survey data along with the survey of the mobile population in the commercial area. Result: The analysis result shows that 883 stores should be maintained considering the overall expenditure and gross sales profit within Cheonan Station in South Chungcheong Province. Currently, considering spending and margins in the Commercial Area, Jinju Central Commercial Area is a place where 222 stores can be sold excessively, and a proper commercial supply plan is needed. Conclusions: In this study, we conducted a demand prediction study in the commercial sector of the most basic sector to regenerate the commercial sector through major regional commercial districts.