• 대기
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• 제17권4호
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• pp.435-453
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• 2007

KEOP (Korea Enhanced Observing Period)-2004 intensive summer observation was carried out from 20 June to 5 July 2004 over the Southwestern part of the Korean peninsula. In this study, the effects of KEOP-2004 intensive observation data on the simulation of precipitation system are investigated using KLAPS (Korea Local Analysis and Prediction System) and PSU/NCAR MM5. Three precipitation cases during the intensive observation are selected for detailed analysis. In addition to the control experiments using the traditional data for its initial and boundary conditions, two sensitivity experiments using KEOP data with and without Jindo radar are performed. Although it is hard to find a clear and consistent improvement in the verification score (threat score), it is found that the KEOP data play a role in improving the position and intensity of the simulated precipitation system. The experiments started at 00 and 12 UTC show more positive effect than those of 06 and 18 UTC. The effect of Jindo radar is dependent on the case. It plays a significant role in the heavy rain cases related to a mesoscale low over Changma front and the landing of a Typhoon. KEOP data produce more strong difference in the 06/18 UTC experiments than in 00/12 UTC, but give more positive effects in 00/12 UTC experiments. One of the possible explanations for this is that : KEOP data could properly correct the atmosphere around them when there are certain amounts of data, while gives excessive effect to the atmospheric field when there are few data. CRA analysis supports this reasoning. According to the CRA (Contiguous Rain Area) analysis, KEOP data in 00/12 UTC experiments improve only the surrounding area, resulting in essentially same precipitation system so the effects remain only in each convective cell rather than the system itself. On the other hand, KEOP data modify the precipitation system itself in 06/18 UTC experiments. Therefore the effects become amplified with time integration.

• 대기
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• 제18권4호
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• pp.299-316
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• 2008

The intensive upper-air observation network was organized over southwestern region of the Korean Peninsula during the Korea Enhanced Observing Program in 2005 (KEOP-2005). In order to examine the effect of additional upper-air observation on the numerical weather forecasting, three Observing System Experiments (OSEs) using Korea Local Analysis and Prediction System (KLAPS) and Weather Research and Forecasting (WRF) model with KEOP-2005 data are conducted. Cold start case with KEOP-2005 data presents a remarkable predictability difference with only conventional observation data in the downstream and along the Changma front area. The sensitivity of the predictability tends to decrease under the stable atmosphere. Our results indicates that the effect of intensive observation plays a role in the forecasting of the sensitive area in the numerical model, especially under the unstable atmospheric conditions. When the intensive upper-air observation data (KEOP-2005 data) are included in the OSEs, the predictability of precipitation is partially improved. Especially, when KEOP-2005 data are assimilated at 6-hour interval, the predictability on the heavy rainfall showing higher Critical Success Index (CSI) is highly improved. Therefore it is found that KEOP-2005 data play an important role in improving the position and intensity of the simulated precipitation system.

• 대기
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• 제15권2호
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• pp.141-148
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• 2005

Currently several important observation programs are planned or being performed both domestically and internationally. In this paper, a brief introduction is provided on international programs such as THORPEX, ARGO and GEOSS as well as a domestic program KEOP. In addition, discussions on various issues related to observations and future visions are provided.

• 대기
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• 제19권4호
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• pp.297-307
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• 2009

The synoptic structures and the dynamic and thermodynamic characteristics of Changma in 2007 are investigated using the ECMWF analysis data and the radiosonde data from KEOP-2007 IOP. The enhancement of the North-Pacific High into the Korean peninsula and the retreat of the Okhotsk High are shown during the onset of Changma and the change of wind component from southwesterly to northwesterly is appeared during the end of Changma. The baroclinic atmosphere is dominant during Changma at most regions over the Korean peninsula except at Gosan and Sokcho. The quasi-barotropic atmosphere is induced at Gosan by warm air mass and Sokcho by cold air mass. Precipitation in the Korean peninsula occurs when dynamic instability is strengthened as the baroclinic and qusi-barotropic structure is weakened. An empirical orthogonal function (EOF) analysis is performed to find the dominant modes of variability in Changma. The first EOF explains the onset of Changma. The second EOF is related to the discrimination for existence and nonexistence of precipitation during Changma period according to the alternation of equivalent potential temperature between middle and lower atmosphere.

• 대기
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• 제18권2호
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• pp.147-158
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• 2008

Domestic IOP (intensive observing period) has mostly been represented by the KEOP (Korea Enhanced Observing Period), which started the 5-yr second phase in 2006 after the first phase (2001-2005). During the first phase, the KEOP had focused on special observations (e.g., frontal systems, typhoons, etc.) around the Haenam supersite, while extended observations have been attempted from the second phase, e.g., mountain and downstream meteorology in 2006 and heavy rainfall in the mid-central region and marine meteorology in 2007. So far the KEOP has collected some useful data for severe weather systems in Korea, which are very important in understanding the development mechanisms of disastrous weather systems moving into or developing in Korea. In the future, intensive observations should be made for all characteristic weather systems in Korea including the easterly in the central-eastern coastal areas, the orographically-developed systems around mountains, the heavy snowfall in the western coastal areas, the upstream/downstream effect around major mountain ranges, and the heavy rainfall in the mid-central region. Enhancing observations over the seas around the Korean Peninsula is utmost important to improve forecast accuracy on the weather systems moving into Korea through the seas. Observations of sand dust storm in the domestic and the source regions are also essential. Such various IOPs should serve as important components of international field campaign such as THORPEX (THe Observing system Research and Predictability EXperiment) through active international collaborations.

• 대기
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• 제19권2호
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• pp.213-226
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• 2009

In order to investigate the characteristics of Changma over the Korean peninsula, KEOP-2007 IOP (Intensive Observing Period) was conducted from 15 June 2007 to 15 July 2007. KEOP-2007 IOP is high spatial and temporal radiosonde observations (RAOB) which consisted of three special stations (Munsan, Haenam, and Ieodo) from National Institute of Meteorological Research, five operational stations (Sokcho, Baengnyeongdo, Pohang, Heuksando, and Gosan) from Korea Meteorological Administration (KMA), and two operational stations (Osan and Gwangju) from Korean Air Force (KAF) using four different types of radiosonde sensors. The error statistics of the sensor of radiosonde were investigated using quality control check. The minimum and maximum error frequency appears at the sensor of RS92-SGP and RS1524L respectively. The error frequency of DFM-06 tends to increase below 200 hPa but RS80-15L and RS1524L show vice versa. Especially, the error frequency of RS1524L tends to increase rapidly over 200 hPa. Systematic biases of radiosonde show warm biases in case of temperature and dry biases in case of relative humidity compared with ECMWF (European Center for Medium-Range Weather Forecast) analysis data and precipitable water vapor from GPS. The maximum and minimum values of systematic bias appear at the sensor of DFM-06 and RS92-SGP in case of temperature and RS80-15L and DFM-06 in case of relative humidity. The systematic warm and dry biases at all sensors tend to increase during daytime than nighttime because air temperature around sensor increases from the solar heating during daytime. Systematic biases of radiosonde are affected by the sensor type and the height of the sun but random errors are more correlated with the moisture conditions at each observation station.

• 대기
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• 제11권3호
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• pp.9-11
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• 2001

• 한국환경과학회지
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• 제16권12호
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• pp.1401-1409
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• 2007

The formation mechanism of the snow cells of the Yellow Sea associated with snowfall over the southwestern part of Korea on 4 February, 2004 has been investigated using special upper-air sounding and radar data obtained for the KEOP(Korea Enhanced Observing Period) Intensive Observing Period(IOP). Results show that the types of snow cells for the selected period are classified into L(Longitudinal)-mode, Low-level convergence, and T(Transverse)-mode with their evolution from L-mode to T-mode. In particular, the existence of low-level warm and humid layer associated with temporally southwesterly inflow for about 4 hours provides a favorable condition in forming the T-mode snow cells. The vertical depth of the T-mode snow cells is deeper than that of L-mode ones due to the southeastward penetration of cold and dry air into relatively warm and humid air. In addition, it is found that wind shear vector between 1000 hPa and 600 hPa is one of the factors which control the orientation of snow cells in formation embedded into the snowbands for the both modes.

• 응용통계연구
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• 제18권2호
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• pp.281-296
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• 2005

본 연구에서는 2004년 기상청 집중관측기간(KEOP)에 수집된 지상관측자료를 사용하여 한반도 남서지방의 지역별(해남 외 7개 지역) 기상인자들의 주기성과 이들이 강수현상에 미치는 영향을 분석하였다. 이를 위하여 기술통계와 스펙트럴분석을 사용하여 주기성을 분석하고, 관측기간 및 지역별 랜덤효과를 반영할 수 있는 일반화 선형모형을 제시하여 강수현상에 미치는 기상인자들의 영향을 분석했다. 분석결과에 의하면 기상인자들과 강수현상은 연관성을 가지며 특정주기에 따라 변동하는 것으로 나타났으며, 기상인자들은 지역에 따라 상이한 패턴으로 강수현상에 영향을 미치는 것으로 나타났다.

• 대기
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• 제13권4호
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• pp.57-70
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• 2003

기상연구소 주요사업 "한반도 악기상 집중관측사업(KEOP)"의 일환으로 2001년 기반공사를 시작하여 2002년 초부터 오토존데, 윈드프로파일러 등 첨단관측장비의 해남기상관측소에 도입 및 설치와 2002년 11월 연구용 도플로 레이더의 (구)무안기상대에 이전 설치로 국가 악기상 집중관측센터는 안정적으로 구축되었다. 이 집중관측센터를 중심으로 기존 기상청 관측망과 연계하여 2002년에 여름철 장마, 태풍 "루사" 그리고 강설과 같은 악기상 집중관측과 국제집중관측프로그램(CAMP/CEOP)에 참여를 위한 고층 및 플럭스 관측자료의 안정적 생산 및 DB 구축 능력 평가를 위한 고층 및 플럭스 집중관측을 국내 대학들과 협력하여 성공리에 실시하였다. 이들 집중관측자료의 초기 분석결과, 국가 악기상 집중관측센터에 설치된 첨단관측장비에서 생산된 관측자료는 악기상 구조 및 발달과정 분석연구 뿐만 아니라 지표 플럭스 연구 활성화에 크게 기여할 것으로 판단되었다. 특히 태풍 "루사" 통과시 오토존데를 이용한 3시간별 고층관측을 통한 태풍 "루사" 중심 구조 분석은 매우 의미 있는 결과로 사료된다. 앞으로 2003년 1월부터 안정적으로 운영되는 윈드프로파일러 자료를 이용하여 악기상 관련 전선 및 하층바람 구조 및 발달 과정 분석을 분석하고, 아울러 연구용 X-밴드 도플러 레이더, 오토존데 관측 자료간의 비교분석으로 윈드프로파일러 관측자료의 정확도를 평가하고자 한다. 광학강우강도계, 마이크로 강수레이더, 연구용 X-밴드 도플러 레이더 그리고 기상청 진도 S-밴드 레이더를 이용하여 악기상 강수시스템의 구조 및 발달 과정 분석할 예정이다. 또한 국가 악기상 집중관측센터는 태풍과 장마, 겨울철 폭설과 한파와 같은 악기상 집중 관측외에 봄과 가을철에 많은 강수를 동반한 저기압 통과시, 황사 발생의 경우 등에 특별관측을 수행하여 특이기상 현상의 이해력을 증진시키는데 활용코자 한다.