• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.337-341
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• 2016

Purpose: Evaluation of atmospheric conditions for proper timing of spray application is important to prevent off-target movement of crop protection materials. Susceptible crops can be damaged downwind if proper application procedure is not followed. In our previous study, hourly data indicated unfavorable conditions, primarily between evening 18:00 hrs in the evening and 6:00 hrs next morning, during clear conditions in the hot summer months in the Mississippi delta. With the requirement of timely farm operations, sub-hourly data are required to provide better guidelines for pilots, as conditions of atmospheric stability can change rapidly. Although hourly data can be interpolated to some degree, finer resolution for data acquisition of the order of 15 min would provide pilots with more accurate recommendations to match the data recording frequency of local weather stations. Methods: In the present study, temperature and wind speed data obtained at a meteorological tower were re-sampled to calculate the atmospheric stability ratio for sub-hour and hourly recommendations. High-precision evaluation of temperature inversion periods influencing atmospheric stability was made considering strength, time of occurrence, and duration of temperature inversion. Results and Discussion: The results indicated that atmospheric stability could be determined at different time intervals providing consistent recommendations to aerial applicators, thereby avoiding temperature inversion with minimal off-target drift of the sprayed liquid.

• Atmosphere
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• v.19 no.4
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• pp.331-344
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• 2009

A sensitivity study has been performed using ARPS (Advanced Regional Prediction System) version 5.2.10 in a downslope windstorm case of 12-13 February 2006. The purpose of this study was to find out the role of the inversion layer of temperature mainly in relation to the strength of the downslope winds over the Yeongdong region located downstream of the Taebaek mountains. Under the conditions of N (Brunt-$V{\ddot{a}}is{\ddot{a}}la$ frequency)=0.008 and N=0.016, the effects of the presence of the inversion layer, its variation of height of the layer, and the depth of the layer were identified. The sensitivity experiments suggested that the inversion layer effected the downstream wind speed of the mountains under both conditions of N=0.008 and N=0.016, and notably when the inversion layer was located near the mountain crest the downstream wind speed of the mountains was strong (~ $27ms^{-1}$) only under the condition of N=0.016. In addition, when the atmosphere was rather stable (N=0.016) and the depth of the layer was relatively thin (765 m) the downstream wind speed of the mountains was the strongest (~ $30ms^{-1}$) among the sensitivity experiments.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.3
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• pp.265-274
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• 1990

The temperature inversions were studied on the basis of Digital Memory Bathythermography(DBT) data collected by training ship, Pusan 402, of the National Fisheries University of Pusan in August 23~25, 1986 and Fisheries Reserach and Development Agency of Korea in August, 1986, The results were as follows; Among the 67 stations of studied area, occurrence frequency of temperature inversion was 58.20%, And the frequency of onefold occurrence of temperature inversion at its profile of each station was 13.42%. of twofold occurrence was 20.80%, and of threefold occurrence was 23.88%. In the studied area, the temperature inversion usually occurred below the 40m depth and its layers also located below the thermocline. The temperature range of its inversion was from 14$^{\circ}C$ to 16$^{\circ}C$. The temperature inversion in the study area was oaused by the interaction between Tsushima Warm Current and Korea Coastal Waters.

• 한국해양학회지
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• v.27 no.4
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• pp.259-267
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• 1992

A survey of CTD casting was taken in April 1991 in the eastern Yellow Sea. The vertical structure of water column consists of the upper mixed warm, the mid cold and the lower warm layers devised clearly by a seasonal thermocline and the temperature inversion. A strongest temperature inversion is found in the southern part of the survey area. Where the low-layer water is $3^{\circ}C$ higher than the mid-layer water. The area of the temperature inversion covers about $100{\;}km{\;}{\times}{\;}100{\;}km$ and it is observed 1.5 month later. The temperature and salinity of the low-layer water shows a core structure in vertical sections and the tongue-like distribution extending from the south to the north, implying that the warm and saline water found in the oceanic front south of the survey area in early spring is advocated to the north over 150 km underneath the Yellow Sea cold water.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.547-555
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• 1995

Melting process of ice in a rectangular cavity with different temperature walls has been studied experimentally. Front shape of ice and melting rate were affected by initial temperature of ice and variation of temperature distribution and density gradient. When the hot wall temperature was below $8^{\circ}C$, the melting rates were higher at the bottom than those of at the top due to the density inversion, but with increasing the hot wall temperature the melting rates at the top were affected by hot wall and were higher than those of at the bottom. When the initial temperature of ice was low, melting rates were low, but with increasing the time melting rates were almost the same with those of each initial temperature of ice.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.441-451
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• 1996

The surface meteorological and upper layer meteorological observation carried out to investigate influences of sea breeze effect on lower layer atmosphere at Gori nuclear power plant for 29∼30 July, 1996. According to surface meteorological data, the inflow of sea breeze was occurred 11:30 on 29 July, 10:30-on 30 July, respectively, at observation site. And the meteorological tower data showed that wind direction of sea breeze was identified as south-westerly, and wind speed of 58 m was 2 times stronger than that of 10 m. It is notworthy that surface inversion layer which built from the night time to daybreak of next day was not broken off by seab reeze's inflow for daytime, and strong inversion layer observed at 47∼243 m with moderately stable class (F) by URC. It was found that strong stable layer of potential temperature appeared at that layer, maximum relative humidity observed at the bottom of inversion layer and maximum mixing ratio observed in the low of inversion layer.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.3
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• pp.75-85
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• 2017

A method to estimate hourly temperature profiles on calm and clear nights was developed based on temporal changes of inversion height and strength. A meteorological temperature profiler (Model MTP5H, Kipp and Zonen) was installed on the rooftop of the Highland Agriculture Research Institute, located in Daegwallyeong-myeon, Pyeongchang-gun, Gangwon-do. The hourly vertical distribution of air temperature was measured up to 600 m at intervals of 50 m from May 2007 to March 2008. Temperature and relative humidity data loggers (HOBO U23 Pro v2, Onset Computer Corporation, USA) were installed in the Jungdae-ri Valley, located between Gurye-gun, Jeollanam-do and Gwangyang-si, Jeollanam-do. These loggers were used to archive measurements of weather data 1.5 m above the surface from October 3, 2014, to November 23, 2015. The inversion strength was determined using the difference between the temperature at the inversion height, which is the highest temperature in the profile, and the temperature at 100 m from the surface. Empirical equations for the changes of inversion height and strength were derived to express the development of temperature inversion on calm and clear nights. To estimate air temperature near the ground on a slope exposed to crops, the equation's parameters were modified using temperature distribution of the mountain slope obtained from the data loggers. Estimated hourly temperatures using the method were compared with observed temperatures at 19 weather sites located within three watersheds in the southern Jiri-mountain in 2015. The mean error (ME) and root mean square error (RMSE) of the hourly temperatures were $-0.69^{\circ}C$ and $1.61^{\circ}C$, respectively. Hourly temperatures were often underestimated from 2000 to 0100 LST the next day. When temperatures were estimated at 0600 LST using the existing model, ME and RMSE were $-0.86^{\circ}C$ and $1.72^{\circ}C$, respectively. The method proposed in this study resulted in a smaller error, e.g., ME of $-0.12^{\circ}C$ and RMSE of $1.34^{\circ}C$. The method could be improved further taking into account various weather conditions, which could reduce the estimation error.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.5
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• pp.386-394
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• 1991

Freezing of saturated porous media contained in a rectangular cavity has been studied experimentally. Water and different diameter glass beads consitituted the liquid and porous media. Solidification front shape, the effects of bead diameter and initial liquid temperature was investigated. When the hot wall temperature was below $4^{\circ}C$, the freezing rate was higher at the top than at the bottom due to the density inversion, but with increasing the hot wall temperature the freezing rate at the top was effected by the liquid temperature and was lower than at the bottom. With increasing the bead diameter, the difference of freezing rate between top and bottom was increased and depends on thermal conductivity. When the liquid temperature was low in the beginning, the freezing rate was high, but with increasing the time almost the same with those of high temperature liquid.

• Textile Coloration and Finishing
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• v.16 no.2
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• pp.1-7
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• 2004

The dyeability of cotton fabrics treated with liquid ammonia was investigated using low-temperature and high-temperature reactive dyes. From the results of dyeing rates of direct dye, the inversion time was shown at 600 hours at $40^{\circ}C$, and however it was shown at 10 minutes at $80^{\circ}C$. This was applied to reactive dyeings. In the low-temperature reactive dyes, the color strength of the fabrics treated with liquid ammonia was lower than that of mercerized fabrics. By contrast, in the high-temperature reactive dyes, the color strength of the fabrics treated with liquid ammonia was higher than that of mercerized one.

• Journal of Advanced Information Technology and Convergence
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• v.8 no.2
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• pp.59-67
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• 2018

The minimum power supply voltage of a typical bandgap current reference (BGCR) is limited by operating temperature and input common mode range (ICMR) of a feedback amplifier. A new BGCR using a bandgap voltage generator (BGVG) is proposed to minimize the effect of temperature, supply voltage, and process variation. The BGVG is designed with proportional to absolute temperature (PTAT) characteristic, and a feedback amplifier is designed with weak-inversion transistors for low voltage operation. It is verified with a $0.18-{\mu}m$ CMOS process with five corners for MOS transistors and three corners for BJTs. The proposed circuit is superior to other reported current references under temperature variation from $-40^{\circ}C$ to $120^{\circ}C$ and power supply variation from 1.2 V to 1.8 V. The total power consumption is $126{\mu}W$ under the conditions that the power supply voltage is 1.2 V, the output current is $10{\mu}A$, and the operating temperature is $20^{\circ}C$.