• Title/Summary/Keyword: synoptic climate field

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60 Years of Korean Meteorological Society on Climate Change (기후변화 연구에 관한 한국기상학회 60년사)

  • Joong-Bae Ahn;Young-Hwa Byun;Dong-Hyun Cha
    • Atmosphere
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    • v.33 no.2
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    • pp.155-171
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    • 2023
  • This paper aims to examine from various perspectives how domestic research studies and projects related to climate change have been conducted to mark the 60th anniversary of the Korean Meteorological Society (KMS). The 『50-year History of the Korean Meteorological Society』, published more than a decade ago, has never dealt with the history of development of individual fields of meteorology such as climate change. Therefore, it is of significance to look at the history of research activities and studies achieved by KMS members in the area of climate change over the past 60 years. The research on climate change in KMS is classified by era from the beginning to the latest and the contents are examined by major research projects at that time. During the past 60 years, climatological research in KMS has been mainly focused on general climate, synoptic climate, and applied climate (urban climate) until the 2000s. However, since the 1990s, climate change has become an important area for climate research. The 2000s are the beginning era of climate change research, since the major projects and researches for climate change has begun in the period. The 2010s can be a time when climate change prediction and monitoring are expanded and refined to meet the rapidly increasing demands for climate information from a wide range of areas. We concluded that the development of the research capabilities of the society over the past 60 years, in particular in the past two decades, in the field of climate change research is remarkable.

Changes in Means and Extreme Events of Changma-Period Precipitation Since mid-Joseon Dynasty in Seoul, Korea (조선 중기 이후 서울의 장마철 강수 평균과 극한강수현상의 변화)

  • Choi, Gwangyong
    • Journal of the Korean Geographical Society
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    • v.51 no.1
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    • pp.23-40
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    • 2016
  • In this study, long-term changes in means and extreme events of precipitation during summer rainy period called Changma (late June~early September) are examined based on rainfall data observed by Chukwooki during Joseon Dynasty (1777~1907) and by modern rain-gauge onward (1908~2015) in Seoul, Korea. Also, characterizations of the relevant changes in synoptic climate fields in East Asia are made by the examination of the NCEP-NCAR reanalysis I data. Analyses of 239-year time series of precipitation data demonstrate that the total precipitation as well as their inter-annual variability during the entire Changma period (late June~early September) has increased in the late 20th century and onward. Notably, since the early 1990s the means and extreme events during the summer Changma period (late June~mid-July) and Changma break period (late July~early August) has significantly increased, resulting in less clear demarcations of sub-Changma periods. In this regard, comparisons of synoptic climate fields before and after the early 1990s reveal that in recent decades the subtropical high pressure has expanded in the warmer Pacific as the advection of high-latitude air masses toward East Asia was enhanced due to more active northerly wind vector around the high pressure departure core over Mongolia. Consequently, it is suggested that the enhancement of rising motions due to more active confluence of the two different air masses along the northwestern borders of the Pacific might lead to the increases of the means and extreme events of Changma precipitation in Seoul in recent decades.

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Numerical Simulation of Effect of Urban Land-use Type and Anthropogenic Heat on Wind Field (지표면 변화와 인공열이 바람장에 미치는 영향에 관한 수치 시뮬레이션)

  • 홍정혜;김유근
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.5
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    • pp.511-520
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    • 2000
  • The urban atmosphere is characterized by th difference in surface and atmospheric environment between urban and more natural area. To investigate th climatic effect of land use type and anthropogenic heat of urban on wind field, numerical simulations were carried out under typical summer synoptic condition. The wind model PNU_MCM(Pusan National University Mesoscale Circulation Model) is based on the three-dimensional Boussinesq equations, taking into account the hydrostatic assumption . Since lane-use differs over every subdivision on Pusan the surface energy budget model includes sub0grid parameterization scheme which can calculate the total heat flux over a grid surface composed of different surfaces. The simulated surface wind agrees well with the observed value, and average over 6 days which represent typical summer lan-sea breeze days, August 1998, i.e. negligible gradient winds and almost clear skies. Urbanization makes sea-breeze enhance at day and reduce land-breeze at night. The results show that contribution of land-use type is much larger than that of anthropogenic heat in Pusan.

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Analysis on Residential Micro Climate of the Urban Heat Island and Oxygen Concentration in Winter (겨울철 열섬 및 산소농도의 측정을 통한 주거지별 국지기후의 특성분석)

  • Hwang Jee Wook;Kim So Chong
    • Journal of Environmental Science International
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    • v.13 no.12
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    • pp.1023-1032
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    • 2004
  • Rapid progress in urbanization has resulted in a change of the micro climate, especially in the urban area. In order to investigate the phenomenon of the heat island in the residential micro climate, a field survey was carried out by 4 sets of the residential type in Jeonju under typical winter synoptic condition. As analytic methode, it is used the comparison on the relation of the Land-to-Coverage Rate to Heat Island and Oxygen Concentration. And as a key question it is asked how stable characteristics of the micro climate will result from the survey of the Heat Island and the Oxygen Concentration, used as indicator. To ensure the trustworthy result of research, it is calculated the critical influence of the wind velocity and the Land-to-Covearage Rate. As a result of comparative analysis, it could be confirmed that the local temperatures in all sets of the residential type were higher than the average temperature in Jeonju. But the housing type A 'exclusive use for housing zone' has relativly the most stable and best living condition. On the contrary the residential type B and D has the worst toward the oxygen concentration in the time zone 9-12 a.m., which didn't reach the minimum of the oxygen concentration $20.5{\%}.$ It means that the higer the development and population density is, the worse is the situation of the Quality of Life in the residential types in accordance with the heat island and oxygon con­centration.

A Study on the Change of Heavy Snow Strength by SST in Influence of Continental Polar Air Mass

  • Park, Geon-Young;Ryu, Chan-Su
    • Journal of Integrative Natural Science
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    • v.7 no.1
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    • pp.39-44
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    • 2014
  • The results of the synoptic meteorological analysis showed that when the cold and dry continental high pressure was extended, heavy snow occurred at dawn when the upper atmosphere cooled. In particular, when the continental high pressure was extended and the upper pressure trough passed through, heavy snow occurred due to the convergence region formed in the west coast area, sometimes in the inland of the Honam area. In addition, it was verified that the changes in the humidity coefficients in the upper and lower layers are important data for the determination of the probability, start/end and intensity of heavy snow. However, when the area was influenced by the middle-latitude low pressure, the heavy snow was influenced by the wind in the lower layer (925 hPa and 850 hPa), the equivalent potential temperature, the convergence field, the moisture convergence and the topography. In Case 2010 (30 December 2010), OSTIA had the best numerical simulation with diverse atmospheric conditions, and the maximum difference in the numerically simulated snowfall between NCEP/NCAR SST and OSTIA was 20 cm. Although there was a regional difference in the snowfall according to the difference in the SST, OSTIA and RTG SST numerical tests, it was not as significant as in the previous results. A higher SST led to the numerical simulation of larger snowfall, and the difference was greatest near Buan in the west coast area.

The Advanced Bias Correction Method based on Quantile Mapping for Long-Range Ensemble Climate Prediction for Improved Applicability in the Agriculture Field (농업적 활용성 제고를 위한 분위사상법 기반의 앙상블 장기기후예측자료 보정방법 개선연구)

  • Jo, Sera;Lee, Joonlee;Shim, Kyo Moon;Ahn, Joong-Bae;Hur, Jina;Kim, Yong Seok;Choi, Won Jun;Kang, Mingu
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.24 no.3
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    • pp.155-163
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    • 2022
  • The optimization of long-range ensemble climate prediction for rice phenology model with advanced bias correction method is conducted. The daily long-range forecast(6-month) of mean/ minimum/maximum temperature and observation of January to October during 1991-2021 is collected for rice phenology prediction. In this study, the concept of "buffer period" is newly introduced to reduce the problem after bias correction by quantile mapping with constructing the transfer function by month, which evokes the discontinuity at the borders of each month. The four experiments with different lengths of buffer periods(5, 10, 15, 20 days) are implemented, and the best combinations of buffer periods are selected per month and variable. As a result, it is found that root mean square error(RMSE) of temperatures decreases in the range of 4.51 to 15.37%. Furthermore, this improvement of climatic variables quality is linked to the performance of the rice phenology model, thereby reducing RMSE in every rice phenology step at more than 75~100% of Automated Synoptic Observing System stations. Our results indicate the possibility and added values of interdisciplinary study between atmospheric and agriculture sciences.

Comparative Evaluation of UAV NIR Imagery versusin-situ Point Photo in Surveying Urban Tributary Vegetation (도심소하천 식생조사에서 현장사진과 UAV 근적외선 영상의 비교평가)

  • Lee, Jung-Joo;Hwang, Young-Seok;Park, Seong-Il;Um, Jung-Sup
    • Journal of Environmental Impact Assessment
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    • v.27 no.5
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    • pp.475-488
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    • 2018
  • Surveying urban tributary vegetation is based mainly on field sampling at present. The tributary vegetation survey integrating UAV NIR(Unmanned Aerial Vehicle Near Infrared Radiance) imagery and in-situ point photo has received only limited attentions from the field ecologist. The reason for this could be the largely undemonstrated applicability of UAV NIR imagery by the field ecologist as a monitoring tool for urban tributary vegetation. The principal advantage of UAV NIR imagery as a remote sensor is to provide, in a cost-effective manner, information required for a very narrow swath target such as urban tributary (10m width or so), utilizing very low altitude flight, real-time geo-referencing and stereo imaging. An exhaustive and realistic comparison of the two techniques was conducted, based on operational customer requirement of urban tributary vegetation survey: synoptic information, ground detail and quantitative data collection. UAV NIR imagery made it possible to identify area-wide patterns of the major plant communities subject to many different influences (e.g. artificial land use pattern), which cannot be acquired by traditional field sampling. Although field survey has already gained worldwide recognition by plant ecologists as a typical method of urban tributary vegetation monitoring, this approach did not provide a level of information that is either scientifically reliable or economically feasible in terms of urban tributary vegetation (e.g. remedial field works). It is anticipated that this research output could be used as a valuable reference for area-wide information obtained by UAV NIR imagery in urban tributary vegetation survey.

A Feasibility Study of a Field-specific Weather Service for Small-scale Farms in a Topographically Complex Watershed (지형이 복잡한 집수역의 소규모농장에 맞춘 기상서비스의 실현가능성)

  • Yun, Jin I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.17 no.4
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    • pp.317-325
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    • 2015
  • An adequate downscaling of synoptic forecasts is a prerequisite for improved agrometeorological service to rural areas in South Korea where complex terrains and small farms are common. In this study, geospatial schemes based on topoclimatology were used to scale down the Korea Meteorological Administration (KMA) temperature forecasts to the local scale (~30 m) across a rural catchment. Then, using these schemes, local temperatures were estimated at 14 validation sites at 0600 and 1500 LST in 2013/2014 and were compared with the observations. The estimation errors were substantially reduced for both 0600 and 1500 LST temperatures when compared against the uncorrected KMA products. The improvement was most notable at low lying locations for the 0600 temperature and at the locations on west- and south-facing slopes for the 1500 LST temperature. Using the downscaled real-time temperature data, a pilot service has started to provide the field-specific weather information tailored to meet the requirements of small-scale farms. For example, the service system makes a daily outlook on the phenology of crop species grown in a given field using the field-specific temperature data. When the temperature forecast is given for next morning, a frost risk index is calculated according to a known relationship of phenology and frost injury. If the calculated index is higher than a pre-defined threshold, a warning is issued and delivered to the grower's cellular phone with relevant countermeasures to help protect crops against frost damage.

1.6 M SOLAR TELESCOPE IN BIG BEAR - THE NST

  • GOODE PHILIP R.;DENKER CARSTEN.J.;DIDKOVSKY LEONID I.;KUHN J. R.;WANG HAIMIN
    • Journal of The Korean Astronomical Society
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    • v.36 no.spc1
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    • pp.125-133
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    • 2003
  • New Jersey Institute of Technology (NJIT), in collaboration with the University of Hawaii (UH), is upgrading Big Bear Solar Observatory (BBSO) by replacing its principal, 65 cm aperture telescope with a modern, off-axis 1.6 m clear aperture instrument from a 1.7 m blank. The new telescope offers a significant incremental improvement in ground-based infrared and high angular resolution capabilities, and enhances our continuing program to understand photospheric magneto-convection and chromospheric dynamics. These are the drivers for what is broadly called space weather - an important problem, which impacts human technologies and life on earth. This New Solar Telescope (NST) will use the existing BBSO pedestal, pier and observatory building, which will be modified to accept the larger open telescope structure. It will be operated together with our 10 inch (for larger field-of-view vector magnetograms, Ca II K and Ha observations) and Singer-Link (full disk H$\alpha$, Ca II K and white light) synoptic telescopes. The NST optical and software control design will be similar to the existing SOLARC (UH) and the planned Advanced Technology Solar Telescope (ATST) facility led by the National Solar Observatory (NSO) - all three are off-axis designs. The NST will be available to guest observers and will continue BBSO's open data policy. The polishing of the primary will be done in partnership with the University of Arizona Mirror Lab, where their proof-of-concept for figuring 8 m pieces of 20 m nighttime telescopes will be the NST's primary mirror. We plan for the NST's first light in late 2005. This new telescope will be the largest aperture solar telescope, and the largest aperture off-axis telescope, located in one of the best observing sites. It will enable new, cutting edge science. The scientific results will be extremely important to space weather and global climate change research.

Using Digital Climate Modeling to Explore Potential Sites for Quality Apple Production (전자기후도를 이용한 고품질 사과생산 후보지역 탐색)

  • Kwon E. Y.;Jung J. E.;Seo H. H.;Yun J. I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.6 no.3
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    • pp.170-176
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    • 2004
  • This study was carried out to establish a spatial decision support system for evaluating climatic aspects of a given geographic location in complex terrains with respect to the quality apple production. Monthly climate data from S6 synoptic stations across South Korea were collected for 1971-2000. A digital elevation model (DEM) with a 10-m cell spacing was used to spatially interpolate daily maximum and minimum temperatures based on relevant topoclimatological models applied to Jangsoo county in Korea. For daily minimum temperature, a spatial interpolation scheme accommodating the potential influences of cold air accumulation and the temperature inversion was used. For daily maximum temperature estimation, a spatial interpolation model loaded with the overheating index was used. Freezing risk in January was estimated under the recurrence intervals of 30 years. Frost risk at bud-burst and blossom was also estimated. Fruit quality was evaluated for soluble solids, anthocyanin content, Hunter L and A values, and LID ratio, which were expressed as empirical functions of temperature based on long-term field observations. AU themes were prepared as ArcGlS Grids with a 10-m cell spacing. Analysis showed that 11 percent of the whole land area of Jangsoo county might be suitable for quality 'Fuji' apple production. A computer program (MAPLE) was written to help utilize the results in decision-making for site-selection of new orchards in this region.