• Title/Summary/Keyword: direction of atmospheric pressure

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Tropical Cyclone Track and Intensity Forecast Using Asymmetric 3-Dimensional Bogus Vortex (비축대칭 3차원 모조 소용돌이를 이용한 열대저기압의 진로 및 강도예측)

  • Lee, Jae-Deok;Cheong, Hyeong-Bin;Kang, Hyun-Gyu;Kwon, In-Hyuk
    • Atmosphere
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    • v.24 no.2
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    • pp.207-223
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    • 2014
  • The bogussing method was further developed by incorporating the asymmetric component into the symmetric bogus tropical cyclone of the Structure Adjustable Balanced Vortex (SABV). The asymmetric component is separated from the disturbance field associated with the tropical cyclone by establishing local polar coordinates whose center is the location of the tropical cyclone. The relative importance of wave components in azimuthal direction was evaluated, and only two or three wave components with large amplitude are added to the symmetric components. Using the Weather Research and Forecast model (WRF), initialized with the asymmetric bogus vortex, the track and central pressure of tropical cyclones were predicted. Nine tropical cyclones, which passed over Korean peninsula during 2010~2012 were selected to assess the effect of asymmetric components. Compared to the symmetric bogus tropical cyclone, the track forecast error was reduced by about 18.9% and 17.4% for 48 hours and 72 hours forecast, while the central pressure error was not improved significantly. The results suggest that the inclusion of asymmetric component is necessary to improve the track forecast of tropical cyclones.

A Study on Spatial Differences in PM2.5 Concentrations According to Synoptic Meteorological Distribution (종관 기상 분포에 따른 PM2.5 농도의 공간적 차이에 관한 연구)

  • Da Eun Chae;Soon-Hwan Lee
    • Journal of Environmental Science International
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    • v.31 no.12
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    • pp.999-1012
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    • 2022
  • To investigate the reason for the spatial difference in PM2.5 (Particulate Matter, < 2.5 ㎛) concentration despite a similar synoptic pattern, a synoptic analysis was performed. The data used for this study were the daily average PM2.5 concentration and meteorological data observed from 2016 to 2020 in Busan and Seoul metropolitan areas. Synoptic pressure patterns associated with high PM2.5 concentration episodes (greater than 35 ㎍/m3) were analyzed using K-means cluster analysis, based on the 900 hPa geopotential height of NCEP (National Centers for Environmental Prediction) FNL (Final analysis) data. The analysis identified three sub-groups related to high concentrations occurring only in Busan and Seoul metropolitan areas. Although the synoptic patterns of high PM2.5 concentration episodes that occur independently in Busan and Seoul metropolitan areas were similar, there was a difference in the intensity of pressure gradient and its direction, which tends to be an important factor determining the movement time of pollutants. The spatial difference in PM2.5 concentration in the Korean Peninsula is due to the difference and direction of the atmospheric pressure gradient that develops from southwest to northeast direction.

Performance Test of 21AFR Lean Fuel Module at Low and High Operating Conditions (21AFR 희박연료모듈의 저압 및 고압 연소성능시험)

  • Han, Yeoung-Min;Ko, Young-Sung;Yang, Soo-Seok;Lee, Dae-Sung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.8
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    • pp.1132-1137
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    • 2002
  • In this paper, the test results of the combustion for 2 IAFR lean fuel models are described. The need for the low emission combustor has been issued from the concern on the increase of green house and the destruction of ozone layer. To evaluate the flow and combustion performance of newly designed 21AFR lean modules, the hydraulic tests in stereolithographic airflows models, the low pressure combustion tests in three injectors model for weak extinction and ignition and the high pressure combustion tests in single sector for NOx, SAE and efficiency are performed. The low pressure tests reveal that the governing parameters in weak extinction and ignition at atmospheric condition are prefilmer length, swirl flow rotation direction, secondary swirl angle and flow split. As a result of combustion test at high pressure, the efficiency and smoke level are satisfied with performance targets, but EINOx of 17.8 is higher than target value of 13.1 The high pressure tests show that the main parameters influenced on NOx are primary swirl angle, swirl flow rotation direction, heatshield exit angle and liner mixing hole location.

Performance Test of 21AFR Lean Fuel Module at Low and High Operating Conditions (21AFR 희박연료모듈의 저압 및 고압 연소성능시험)

  • Han, Yeoung-Min;Ko, Young-Sung;Yang, Soo-Seok;Lee, Dae-Sung
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.858-863
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    • 2001
  • In this paper, the test and result of flow and combustion for 21AFR lean fuel models are described. The necessity to develop the low emission combustor has been issued from the concern on the increase of green house and the destruction of ozone layer. To evaluate the flow and combustion performance of new designed 21AFR lean modules, the hydraulic tests in stereo lithographic airflows models, the low pressure combustion tests in three injectors model for weak extinction and ignition and the high pressure combustion tests in single sector for NOx, SAE and efficiency are performed. The low pressure tests reveal that the governing parameters in weak extinction and ignition at atmospheric condition are prefilmer length, swirl flow rotation direction, secondary swirl angle and flow split. As a results of combustion test at high pressure, the efficiency and smoke level are satisfied with performance targets, but EINOx of 17.8 is higher than target value of 13.1. The high pressure tests show that the main parameters influenced on NOx are primary swirl angle, swirl flow rotation direction, heatshield exit angle and liner mixing hole location.

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Typical Patterns of the Heavy Rains and their Associated Atmospheric Circulation (전형적인 호우와 연관된 대기순환)

  • Hi-Ryong Byun;Mo-Rang Her
    • Journal of Environmental Science International
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    • v.7 no.2
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    • pp.177-184
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    • 1998
  • The spatial rainfall distributions accompanied by the heavy rainfalls in the Korean peninsula were class-sified to 6 typical patterns and synoptic characteristics of each pattern were muined. 274 cases of heavy rainfall events occurred for 10 years from 1981 through 1990 were used for thls study In the 4 types of them, heavy rainfalls are not by the strongly developed but by the rapidly deepening low pressure systems. which have a wall defiried low and high level jets before arrival to the Korean peninsula. In another 2 types, heavy rainfall are due to speciauy developed surface low pressure system. Most of the heavy rain areas are associated with the location of the low level Jets and their direction and with the position of surface warm front. In the 4 types, the heavy rain areas extend In zonal direction. And the latitudinal locations of these areas are associated with the polar low center or strong main trough over 500 hPa level. The more northwestern part of the Asla the low locates the higher latitude in the Korean Peninsula the rainfall concentration occurs at. It is also known that the seasonal drifting of the lows have some relations to the procession of summer monsoon but its characteristics change year by year.

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A Study on Treatment Efficiency of Toluene and CO2 using Vortex Cyclones (보텍스 사이클론을 이용한 Toluene과 CO2 처리효율에 관한 연구)

  • 임계규
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.4
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    • pp.493-501
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    • 2004
  • The principle of vortex tube and cyclone was introduced to enhance the treatment efficiency of waste air streams containing particulate matters, toluene, and others developed by Hangreen Tech, Ltd. and Hoseo Chemical and Industrial Technology R&D Center. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by vortex tube and Joule-Thomson expansion. The pressurized air was introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube. Easily condensible vapors such as toluene. carbon dioxide, and water vapor were adsorbed enforcedly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves. These types of coagulation or condensation rates were rapidly promoted as the diameter being growing up. The maximum removal efficiency for carbon dioxide and toluene was achieved to about 87 and 90 percent, respectively. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 30%. An optimum value was observed within the range of the tested temperatures at a fixed pressure. In conclusion. it could be identified that the treatment efficiency would be depended on the pressure of the process air introduced and physical and chemical characteristics of waste air streams containing target materials for a designed system. The final design parameters should be decided depending upon the given system and target materials.

Analysis on Actual Condition of Usage and Safety Management for CNG Pressure Vessel in Bus (CNG버스 내압용기 사용 및 안전관리 실태 분석)

  • Kim, Eui Soo
    • Journal of the Korean Society of Safety
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    • v.34 no.4
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    • pp.6-14
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    • 2019
  • There are about 38,977 CNG cars and 247 natural gas vehicle charging stations in operation in order to improve the urban air environment. With the introduction of natural gas vehicles, the atmospheric environment, which was the main cause of air pollution in the metropolitan area, was remarkably improved. However, unlike these positive effects, CNG bus accidents, which occurred more than 10 times since 2005, have caused concern among the majority of citizens using public transportation. It is necessary to make a judgment on the feasibility and future direction of CNG pressure vessel safety management that can safeguard the safety of CNG pressure vessel at the time of starting. In this study, we investigates production and use of CNG vessel, the current status of safety management of CNG bus transportation companies & charging stations and then proposes measures to prevent accident recurrence and safety management based on the actual situation investigation and analysis.

Effect of Inactivating Salmonella Typhimurium in Raw Chicken Breast and Pork Loin Using an Atmospheric Pressure Plasma Jet

  • Kim, Hyun-Joo;Yong, Hae In;Park, Sanghoo;Kim, Kijung;Bae, Young Sik;Choe, Wonho;Oh, Mi Hwa;Jo, Cheorun
    • Journal of Animal Science and Technology
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    • v.55 no.6
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    • pp.545-549
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    • 2013
  • The optimal conditions for applications of an atmospheric pressure plasma (APP) jet for the inactivation of Salmonella Typhimurium in chicken breast and pork loins were investigated. APP jet treatment for 10 min (versus 5 minutes) showed a higher inactivation of S. Typhimurium in an agar plate, with the best effect at a distance of 20 mm. A treatment on both sides (both-side treatment) for 2.5 + 2.5 min showed a greater inhibition on S. Typhimurium growth compared to single-side treatment for 5 min, with reduction levels of 0.66 log CFU/g in chicken breast and 1.33 log CFU/g in pork loin, respectively. However, there was no significant difference between single-side treatment for 10 min and both-side treatment for 5 + 5 min in chicken breasts and pork loin samples. In conclusion, APP jet treatment conditions, including distance, time, and direction, may affect the inactivation efficiency of S. Typhimurium. In this experiment, distance of 20 mm and both-side treatment were the best conditions. Therefore, the optimal APP jet treatment conditions were evaluated to maximize its practical efficiency.

The WISE Quality Control System for Integrated Meteorological Sensor Data (WISE 복합기상센서 관측 자료 품질관리시스템)

  • Chae, Jung-Hoon;Park, Moon-Soo;Choi, Young-Jean
    • Atmosphere
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    • v.24 no.3
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    • pp.445-456
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    • 2014
  • A real-time quality control system for meteorological data (air temperature, air pressure, relative humidity, wind speed, wind direction, and precipitation) measured by an integrated meteorological sensor has been developed based on comparison of quality control procedures for meteorological data that were developed by the World Meteorological Organization and the Korea Meteorological Administration (KMA), using time series and statistical analysis of a 12-year meteorological data set observed from 2000 to 2011 at the Incheon site in Korea. The quality control system includes missing value, physical limit, step, internal consistency, persistence, and climate range tests. Flags indicating good, doubtful, erroneous, not checked, or missing values were added to the raw data after the quality control procedure. The climate range test was applied to the monthly data for air temperature and pressure, and its threshold values were modified from ${\pm}2{\sigma}$ and ${\pm}3{\sigma}$ to ${\pm}3{\sigma}$ and ${\pm}6{\sigma}$, respectively, in order to consider extreme phenomena such as heat waves and typhoons. In addition, the threshold values of the step test for air temperature, air pressure, relative humidity, and wind speed were modified to $0.7^{\circ}C$, 0.4 hPa, 5.9%, and $4.6m\;s^{-1}$, respectively, through standard deviation analysis of step difference according to their averaging period. The modified quality control system was applied to the meteorological data observed by the Weather Information Service Engine in March 2014 and exhibited improved performance compared to the KMA procedures.

On the Prediction and Variation of Air Pollutants Concentration in Relation to the Meteorological Condition in Pusan Area (기상조건에 따른 부산지역 대기오염물질 농도변화와 예측에 관한 연구)

  • 정영진;이동인
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.3
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    • pp.177-190
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    • 1998
  • The concentrations of air pollutants In large cities such as Pusan area have been increased every year due to the increasing of fuels consumption at factories and by vehicles as well as the gravitation of the population. In addition to the pollution sources, time and spatial variation of air pollutants concentration and meteorological factors have a great influence on the air pollution problem. Especially , its concentration is governed by wind direction, wind speed, precipitation, solar radiation, temperature, humidity and cloud amounts, etc. In this study, we have analyzed various data of meteorological factors using typical patterns of the air pressure to investigate how the concentration of air pollutants is varied with meteorological condition. Using the relationship between meteorological factors (air temperature, relative humidity, wind speed and solar radiation) and the concentration of air pollutants (SO2, O3) , experimental prediction formulas for their concentration were obtained. Therefore, these prediction formulas at each meteorological factor in a pressure pattern may be roughly used to predict the air pollutants concentration and contributed to estimate the variation of its value according to the weather condition in Pusan city.

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