• Title, Summary, Keyword: Minimum Temperature

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The inference of minimum temperature of the solar atmosphere from the FISS data

  • Moon, Byeongha;Chae, Jongchul;Kang, Juhyeong;Oh, Suyeon
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.58.1-58.1
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    • 2018
  • In the solar atmosphere, below the region of temperature minimum, temperature decreases with height and above it, temperature increases with height. Therefore the inference of temperature minimum is a basis of the study about the solar atmosphere and heating problem. The temperature of the temperature minimum region can be inferred from acoustic cutoff frequency. According to a recent study the acoustic cutoff frequency is related to the peak frequency of the power spectrum the chromospheric three-minute velocity oscillations. Using this relationship, we infer the temperature of temperature minimum. The three minute velocity oscillation and its power spectrum are obtained for a pore observed with the Fast Imaging Solar Spectrograph (FISS) $H{\alpha}$ band. We present the inferred temperature and compare it with the temperature of Maltby model. We also investigate the effect of the inclination of magnetic field on the temperature minimum.

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The Calculation of the Maximum and Minimum Temperature Times for Korea Major City. (대한민국 주요도시의 최고온도 및 최저온도 발생시각 산출)

  • Noh, Kyoung-Hwan;Lee, Kwan-Ho;Yoo, Ho-Chun
    • 한국태양에너지학회:학술대회논문집
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    • pp.63-68
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    • 2008
  • Efforts tp overcome the current challenge of global warming and abnormal temperature are being taken around the world. According to a report, average temperature of Korea has increased by about $0.8^{\circ}C$ for a century. In particular, temperature has rapidly increased since year 2000. Climate changes have brought remarkable changes in our lives. For example, agricultural field will see changes in crops and production. Energy used to maintain and manage architectures will be changed as well. In order to actively cope with rapidly changing global climate which drives changes from the basic behavior of our lives to subtle changes, international cooperation and researches are performed around the word. For instance, as a part of these global efforts, research on typical meterological data for computer simulation program to evaluate architecture energy performance is in progress in Korea. In order to conduct research on typical meterological data in format of data per time, reference regarding monthly maximum/minimum temperature time is required. Unfortunately, however, reference regarding maximum/minimum temperature time hasn't been defined in Korea. Therefore, this study aims to provide fundamental data essential for various researches by calculating maximum/minimum temperature time of major cities across Korea. According to the study, maximum temperature occurs at 3 p.m and minimum temperature occurs at 5 a.m or 6 a.m. respectively, in overall areas.

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Study on the Climate Change and the Urbanization Effect in Busan (부산의 도시기후 변화 경향과 도시화 효과에 관한 연구)

  • Park, Myung-Hee;Lee, Joon-Soo;Ahn, Ji-Suk;Shu, Young-Sang;Han, In-Seng;Kim, Hae-Dong
    • Journal of Environmental Science International
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    • v.21 no.4
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    • pp.401-409
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    • 2012
  • This study examines the climatological variability of urban area and the increase of temperature by urbanization using the observed data of Busan and Mokpo during the last 100 years (1910~2010). The results are as follows. First, the maximum temperature in Busan during the last 100 years has increased by $1.5^{\circ}C$ while average temperature and the minimum temperature have increased by $1.6^{\circ}C$ and $2^{\circ}C$. In Mokpo, the maximum temperature and average temperature have increased by $1^{\circ}C$ and the minimum temperature has increased by $0.8^{\circ}C$. The increase of urban temperature appeared to be higher in Busan than in Mokpo by $0.5^{\circ}C{\sim}1.2^{\circ}C$. Second, as for the change in temperature before and after urbanization, the maximum temperature, average temperature and the minimum temperature during last 50 years compared to the previous 50 years have increased about $1.5^{\circ}C$, $1.6^{\circ}C$ and $2.1^{\circ}C$, however, the predicted temperature after removing urbanization effect was estimated to be increased by $1^{\circ}C$. The proportion that urbanization takes on the overall increase of temperature appeared to be 33% at the maximum temperature, 37.5% at average temperature and 52.3% at the minimum temperature, thus the proportion of urbanization appeared to be maximized at the minimum temperature.

A Study on Autoignition Characteristics of Methylmethacrylate-butadiene-styrene Copolymer (MBS 공중합물의 자연발화 특성에 관한 연구)

  • 목연수;최재욱
    • Journal of the Korean Society of Safety
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    • v.16 no.3
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    • pp.83-88
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    • 2001
  • This study was preformed by measuring the minimum ignition temperature of MBS according to the change of sample vessel size and the minimum ignition temperature of MBS dust cloud The minimum ignition temperature of MBS product decreased as the vessel size was large, and it was obtained in the range from $120.5^{\circ}C$ to $94.5^{\circ}C$ and the apparent activation energy was obtained with 32.94Kcal/mol. The minimum ignition temperature of MBS dust cloud was measured by using Godbert-Greenwald furnace and it was obtained at $407^{\circ}C$ with the sample of 0.4g in the air and the ignition of dust cloud was not occurred below 13% oxygen concentration.

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The Weather Characteristics of Frost Occurrence Days for Protecting Crops against Frost Damage (서리 피해 방지를 위한 서리 발생일의 기상 특성에 대한 연구)

  • Kwon, Young-Ah;Lee, Hyo-Shin;Kwon, Won-Tae;Boo, Kyung-On
    • Journal of the Korean Geographical Society
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    • v.43 no.6
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    • pp.824-842
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    • 2008
  • The main objective of the study was to analyze the weather conditions of frost occurrence for protecting crops against frost damage in Korea. The primary data used for the analysis of meteorological characteristics of frost occurrence days are the airmass pattern, minimum temperature, grass minimum temperature, daily temperature range, relative humidity, minimum relative humidity, mean wind speed in autumn and spring. Frost often occurs when the migratory anticyclone passes the southwest of Korea. The importance of grass minimum temperature measurements for agricultural purposes has previously been recognized. The grass minimum thermometer is capable of detecting ground frosts which are often not recorded by the minimum thermometer. The minimum temperature of frost occurrence days is above $0^{\circ}C$ in the coastal area, but the grass minimum temperature of frost occurrence days is below $0^{\circ}C$ in the whole area. The daily temperature of frost occurrence days is about 9 to $12^{\circ}C$ in the coastal area and is over $14^{\circ}C$ in the inland area. The minimum relative humidity of frost occurrence days is about 30 to 50%. The mean wind speed of frost occurrence days is less than 2m/sec.

A Study on the Distributions of Minimum Temperature during January in the Central Region of South Korea: focused on Minimum Temperature at Cheorwon (기압배치형별 중부지방의 1월 최저기온 분포에 관한 연구: 철원의 최저기온을 중심으로)

  • Lee, Seungho;Jang, Jiwon
    • Journal of the Korean Geographical Society
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    • v.49 no.1
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    • pp.32-44
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    • 2014
  • This study aimed to analyze the characteristic of the distribution of minimum temperature during January in the central region of South Korea and to investigate causes for the occurrence of extreme minimum temperature in Cheorwon. January temperature distribution data which were collected from 25 weather stations in central area from 1991 to 2010 were investigated, and the difference of temperature between Cheorwon and the other stations in central region, such as Chuncheon, Hongcheon, Bonghwa, Daegwallyoung, Wonju and Jecheon were analyzed by the type of atmospheric pressure system. Daily mean temperature and mean of daily minimum temperature appear to be low at Cheorwon and at the sites in high altitudes, but the frequency of extreme cold wave such as below $-15^{\circ}C$ is also noticeable in Cheorwon. When the Siberian High has expanded and migratory anticyclone has moved onto the north of the Korean Peninsula, the temperature at Cheorwon is relatively low. Furthermore it shows a lesser difference between Cheorwon and the compared stations when the migratory anticyclone affected the area, even at basin like Bonghwa, Jecheon more lower than Cheorwon.

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The Estimation of Urbanization Effect in Global Warming over Korea using Daily Maximum and Minimum Temperatures (최고, 최저기온을 이용한 우리나라 기온변화에서의 도시화효과 분석)

  • Koo, Gyo-Sook;Boo, Kyung-On;Kwon, Won-Tae
    • Atmosphere
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    • v.17 no.2
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    • pp.185-193
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    • 2007
  • This study investigates urbanization effect in warming trend of surface air temperature over Korea. The data used in this study consist of the daily minimum and maximum temperatures during the period of 32 years(1968-1999) from 16 stations of KMA. To calculate magnitude and trend of urbanization effect, stations were classified into urban and rural stations using population statistics. Urban stations were defined as those with population densities greater than 1000 persons per kilometer squared in 1995. The others were defined as rural stations. The urban stations were also subdivided into two groups according to their population totals. For estimates of urban effect magnitude, temperature change was calculated by comparing 16-year mean values between 1968-83 and 1984-99. Then, the difference between each urban station and every rural station was calculated. During the analysis period of 32 years, maximum temperature increase is $1.22^{\circ}C$. In the total temperature increase, urban effect is estimated by 28.7%. For minimum temperature, it becomes larger by about 10% than that in maximum temperature. Therefore, urban effect in an increasing trend of minimum temperature is 38.9% in the change of $1.13^{\circ}C$.

Stability of superconductor by integration formula

  • Seol, S.Y.
    • Progress in Superconductivity and Cryogenics
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    • v.21 no.3
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    • pp.1-5
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    • 2019
  • The superconductor stability theories are consistently described by the integral formula. If the defined stability function is a simple decreasing function, it becomes a cryogenic stability condition. If the stability function has a maximum value and a minimum value, and the maximum value is less than 0, then it is a cold-end recovery condition. If the maximum value is more than 0, it can be shown that the unstable equilibrium temperature, that is, the MPZ (minimum propagation zone) temperature distribution can exist. The MPZ region is divided into two regions according to the current ratio. At the low current ratio, the maximum dimensionless temperature is greater than 1, and at the relatively high current ratio, the maximum dimensionless temperature is less than 1. In order to predict the minimum quench energy, the dimensionless energy was obtained for the MPZ temperature distribution. In particular, it was shown that the dimensionless energy can be obtained even when the MPZ maximum temperature is 1 or more.

Investigation of Urban High Temperature Phenomenon in Summer using the High Density Ground Monitoring System in Daegu Metropolitan Area (지상 고밀도 관측 시스템을 이용한 대구의 여름철 고온현상 조사)

  • Kim, Sang-Heon;Cho, Chang-Bum;Kim, Hae-Dong
    • Journal of Environmental Science International
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    • v.23 no.9
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    • pp.1619-1626
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    • 2014
  • We analyzed diurnal variations in the surface air temperature using the high density urban climate observation network in Daegu metropolitan city, the representative basin-type city in Korea, in summer, 2013. We used a total of 28 air temperature observation points data(16 thermometers and 12 AWSs). From the distribution of monthly average air temperature, air temperature at the center of Daegu was higher than the suburbs. Also, the days of daily minimum air temperature more than or equal to $25^{\circ}C$ and daily maximum air temperature more than or equal to $35^{\circ}C$ at the schools near the center of Daegu was more than those at other schools. This tendency appeared more clearly on the days of daily minimum air temperature more than or equal to $25^{\circ}C$. Also, the air temperature near the center of the city was higher than that of the suburbs in the early morning. Thus it was indicated that the air temperature was hard to decrease as the bottom of the basin. From these results, the influence of urbanization to the formation of the daily minimum temperature in Daegu was indicated.

Influence of Temperature and Relative Humidity in Infection of Nosema bombycis (Microsporidia: Nosematidae) and Cross-infection of N. mylitta on Growth and Development of Mulberry Silkworm, Bombyx mori

  • Chakrabarti, Satadal;Manna, Buddhadeb
    • International Journal of Industrial Entomology
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    • v.17 no.2
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    • pp.173-180
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    • 2008
  • The influence of temperature and relative humidity in infection and cross-infection of Nosema bombycis and N. mylitta respectively in mulberry silkworm, Bombyx mori L. on larval mortality, multiplication of pathogens, larval weight and growth rate in three different seasons were studied. Seasons were selected in such condition, when very less fluctuations between minimum and maximum temperature and minimum and maximum relative humidity ($25{\sim}28^{\circ}C$ and $65{\sim}72%$ R.H) was observed i.e., season-1. Fluctuations between minimum and maximum temperature were less ($28.05{\sim}34.50^{\circ}C$) but R.H % was more ($55{\sim}81%$) in season-2. Fluctuations between minimum and maximum temperature and R.H % were more ($20.00{\sim}40.5^{\circ}C$ and $64.00{\sim}90.00%$) in season-3. Growth rate of microsporidian-infected silkworm is directly related to the prevailing temperature and relative humidity in silkworm. Silkworm can tolerate slight variation of temperature but slight variation of relative humidity disfavours the development of silkworm and favours the multiplication of pathogens.