• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.144-155
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• 2015

Since the relocation project of equipment in 2011, the overall circumstances of KMA's agrometeorological observation have been significantly improved. Some concerns, however, emerged as a result of the evaluation of observational circumstances in terms of quality assurance after the field surveys on all stations. In order to improve the situation, we suggest: (1) establishment of clear management responsibilities, (2) enhancement of mutual cooperation system between relevant organizations, (3) detailed records of the changes in the observational circumstances, (4) standardization of equipment and sensors, (5) installation of unified information boards, (6) transfer of inappropriate facilities to an adjacent cropland and (7) setup of automated evaporation pan. In order to effectively utilize the high-quality data obtained through improvement of observational circumstances and an elaborate quality control, it is recommended to publish and disseminate regular reports on agrometeorological observations. To produce such a report on a trial basis, we have investigated different types of regular reports issued by domestic and foreign organizations, publication periods, geographical scope, main contents and amount. Based on our current situation, it would be beneficial to learn from the cases of Germany and Canada, which summarize mainly the distinctive agrometeorological phenomena occurred over the past years across the country.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.29-40
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• 2011

In this study, the effects of an urban thermal environment on air quality were investigated using hourly surface weather observation data and air quality data over six summers from 2000 to 2005 in two cities on the Korean Peninsula. One, the city of Daegu, is representative of basin topography and the other, the city of Busan, represents a coastal area. It is known that the characteristics of an urban thermal environment are represented as an "urban heat island". Here, we focus on the nighttime urban thermal environment, which is called a "tropical night", during the summer. On tropical nights in Busan, the temperature and cloud cover levels were higher than on non-tropical nights. Wind speed did not appear to make a difference even on a tropical night. However, the frequency of southwestern winds from the sea was higher during tropical nights. The prevailing southwest winds in all areas meant an inflow of air from the sea. So at most of the air quality stations, the ozone concentration during tropical nights was lower than during non-tropical nights. In Daegu, the tropical nights had higher temperatures and cloud covers. Despite these higher temperatures, the ozone concentration during the tropical nights was lower than that on non-tropical nights at most of the air quality stations. This feature was caused by low irradiance, which in turn caused an increased cloud cover. Wind speed was stronger during the tropical nights and dispersed the air pollutants. These meteorological characteristics of the tropical nights reduced ozone concentrations in the Daegu Basin.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.2
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• pp.83-94
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• 2022

In order to actively prepare to frost damage that occurs in the process of growing crops, the spatial and temporal distribution of frost occurrence in South Korea was derived using frost observation data from 20 regions over the past 21 years (2000~2020). The main products are the number of frost days, first frost day, and last frost day by region. And the climatic trends of these results were identified by performing the Mann-Kendall trend test and Sen's slope estimator. In South Korea, a lot of frost occurs in the inland area to the west of the Taebaek and Sobaek Mountains. Relatively closer to the coastal area, the number of frost days is small, the first frost day is slow, and the last frost day is early. The east coast region has fewer frost days, the first frost day is later, and the last frost day is earlier than the west coast region. The southern sea, the southeastern sea region, and the island region rarely experience frost. As a result of the annual time series trend analysis, although South Korea is a country where climate warming is progressing, there was no trend in reducing the number of frost days and slowing the first frost day, and it was found that the last frost day is delayed by 0.5 days per year.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.91-97
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• 2009

It is undertaken systematization of results of satellite and ground observation parameters characterizing a current condition and climatic variability of two selected geographical areas. One of them covers territory of Azerbaijan and another covers a wide area of Caspian See region. Average values and mean square deviations of following values are investigated: outgoing long wave radiation during a day and night (in nebulosity and cloudless). absorbed within a day of the stream of a sunlight of the system in "a terrestrial surface-atmosphere". degree of a covering by clouds of the selected areas during a day and at night, ground temperature values of air. pressure and speed of a wind. Monthly average values of corresponding parameters create a basis of suggested investigations. It has been presented features of a time course of investigated parameters for each month and year in the whole due to the continuously observations since 1982-2000. The scientific problem consists that there are no existed models which authentically would be cover the main aspects of a realities specified changes: they are identified by economic activities. growth of the population and other features of development of a human society or internal fluctuations of biogeophysical/climatic system. Possibilities of predictability of biosphere and climate changes depend on available timely supervision. adequacy of construction of appropriate models. understanding of mechanisms of direct and feedback influences in such complicated systems.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.3-6
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• 2002

In this study, we investigate the atmospheric environment changes in the aspect of optical remote sensing using surface observation data from 1971 to 2000 of Korea Meteorological Administration. Visibility, spatially averaged over Korean peninsula, is systematically reduced from about 28km to 18km during the last 30 years. It means that atmospheric conditions for the optical remote sensing over Korean peninsula are growing worse and worse due to the degradation of air quality. The 30-year average of cloud amount shows a strong seasonal variation, maximum(75%) in summer and minimum (35%) in autumn. Precipitation also shows a very similar variation pattern with cloud. The temperature and sea level pressure show a opposite seasonal change pattern, maximum(minimum in SLP) in summer and minimum(maximum in SLP) in winter, respectively. Relative humidiy(RH) is one of the variables mostly affected by urbanization or urban heat island. As a results, annual mean RH is decreased from 73% to 68% during last 30 years. When we take into account the favorable and unfavorable factors all together, summer and autumn are the worst and the best season for optical remote sensing in Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.515-528
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• 2003

The characteristics of one year observation aerosol data in Seoul, 200 I was studied using an OPC (Optical Particle Counter). The size resolved aerosol number concentrations of 0.3 ∼ 25 11m were measured. The results were compared with PM$_{10}$ mass concentration data under various meteorological conditions including dust and precipitation events. For fine particles whose diameter is less than 2.23 ${\mu}{\textrm}{m}$, the number concentration increases in the early morning which is considered due to transportation. while the coarse mode particles increase during daytime. This increase can be explained as local sources and human activities near sampling site. Hourly averaged data show that there exists diurnal variation. Generally, PM$_{10}$ data showed a similar tendency with OPC data. The size resolved OPC data showed that the particles of 0.5 ∼ 3.67 ${\mu}{\textrm}{m}$ are positively correlated with PM$_{10}$ data. The accumulated volume fraction of size resolved aerosol concentration in 0.5 ∼ 10 ${\mu}{\textrm}{m}$ showed that 0.5 ∼ 2.23 ${\mu}{\textrm}{m}$ particles occupied 59.2% of total aerosol volume of 0.5 ∼ 10 ${\mu}{\textrm}{m}$./TEX>.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.199-210
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• 2013

Detailed 3 dimensional structure of Asian dust plume has been analyzed from the retrieved aerosol data from two different satellites which are the Korea's $1^{st}$ geostationary satellite, namely the Communication, Ocean, Meteorological Satellite (COMS) spacecraft launched in 2010, and the NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). COMS spacecraft provides the first time resolved aerial aerosol maps by the systematically well-calibrated multispectral measurements from the Geostationary Ocean Color Imager (GOCI) instrument. GOCI data are used here to evaluate intensity, spatial distribution, and long-range transport of Asian dust plume during 1~2 May 2011. We found that the strong Asian dust plume showing AOT of 2~5 was lofted to the altitude around 2~4 km above the Earth's surface and transported over Yellow Sea with a speed of about 25 km/hr. The CALIPSO extinction coefficient and particulate depolarization ratio (PDR) profiles confirmed that nonspherical dust particles were enriched in the dust plume. This study is a first example of quantitative integration of GOCI and CALIOP measurements for clarifying the overall structure of an Asian dust event.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.2
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• pp.191-198
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• 1995

In order to evaluate the distribution and behaviour of atmospheric particulate metals in high-altitude area, we collected 22 aerosol samples using a high volume air sampler at Soback Mt. Meteorological Observation Station from Jan. to Nov. 1993 and analysed for metals (Al, Fe, Mg, Na, Ca, Mn, Co, Ni, Cu, Zn, Cd, and Pb) with ICP/AES and ICP/MS. Although sampling site is located in high-altitude and far from local sources of atmospheric pollutants, enrichments of metals are 2 times higher than those of western coastal reural area. This fact may imply that of metallic pollutants in the coastal rural site were came from further western side (e.g. China), atmospheric metals in this study area contain the signal of metropolitan cities located in the main wind direction (NNW). Sea salts are negligible in the aerosol particle population because reference elements of sea salts (Na, Mg) are all originated from soil particles. The contents of soil particles in aerosols are highest in spring and lowest in winter. Atmospheric enriched elements (Ni, Cu, Zn, Cd and Pb) are diluted with soil particles, especially during the yellow sand period. The results of factor analysis suggest possibility of interpreting their chemical significance in terms of sources (soil, pollutants) and gas-particle conversion processes (formation of ammonium sulfates, ammonium nitrates and/or their mixtures).

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.3
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• pp.345-360
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• 2004

The late sea-breeze and its impacts on ozone distributions were investigated during April to September from 1998 to 2002, in the Busan metropolitan area (including surrounding areas) using the surface ozone concentrations (obtained at 9 monitoring sites), local meteorological variables (obtained near the shore), together with synoptic data. The urban scale ozone concentration was also simulated using the MM5/UAM-V to better understand the role of late sea-breeze in Busan. The results from observation study showed that most of the late sea-breeze occurred when weak offshore synoptic flow (northwesterly) suppressed development of sea - breeze, and the ozone concentration level and frequencies exceeding ozone standard increased with the onset time of sea breeze. We also found that the late sea-breeze clearly induces relatively weak wind speed and high temperature during the daytime As a result it enhances the photochemical ozone accumulation and delays the occurrence time of the averaged maximum ozone concentrations. The results of simulation for high ozone episode (24 August, 2001) by MM5/UAM -V revealed that the late sea-breeze interacted with weak offshore synoptic wind can contribute significantly to high ozone concentration in the coastal urban area. The simulated horizontal and vertical distribution of ozone concentration indicated that ozone can be accumulated over the sea under stagnant condition and return to the land in the late afternoon with the sea breeze, suggesting both the relationship between late sea-breeze and recirculation and the importance of late sea -breeze effects influencing severe ozone pollution in Busan.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.63-72
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• 2005

In order to understand regional wind characteristics and to estimate offshore wind resources, a wind map of the Korean Peninsula was established using remote-sensing data from the satellite, U.S. NASA Quik SCAT which has been deployed for the Sea Winds Project since 1999. According to the linear regression result between the wind map data and in-situ marine-buoy data, the correlation factor was greatly improved up to 0.87 by blending the remote-sensing data of Quik SCAT with U.S. NCEP/NCAR CDAS reanalysis data to eliminate precipitation interference and to increase temporal resolution. It is found from the established wind map that the wind speed in winter is prominent temporally and the South Sea shows spatially high energy density over the wind class 6. The reason is deduced that the north-west winds through the Yellow Sea and the north-east winds through the East Sea derived by the low pressure developed in Japan are accelerated passing through the Korea Channel and formed high wind energy region in the South Sea; the same trends are confirmed from the statistical analysis of the meteorological observation data of KMA.