• 대기
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• 제30권4호
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• pp.347-360
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• 2020

The automatic algorithm optimized for the Korean Peninsula was developed to detect and track the center of typhoon based on a geometrical method using high-resolution retrieved WISSDOM (WInd Syntheses System using DOppler Measurements) wind and reflectivity data. This algorithm analyzes the center of typhoon by detecting the geometric circular structure of the typhoon's eye in radar reflectivity and vorticity 2D field data. For optimizing the algorithm, the main factors of the algorithm were selected and the optimal thresholds were determined through sensitivity experiments for each factor. The center of typhoon was detected for 5 typhoon cases that approached or landed on Korean Peninsula. The performance was verified by comparing and analyzing from the best track of Korea Meteorological Administration (KMA). The detection rate for vorticity use was 15% higher on average than that for reflectivity use. The detection rate for vorticity use was up to 90% for DIANMU case in 2010. The difference between the detected locations and best tracks of KMA was 0.2° on average when using reflectivity and vorticity. After the optimization, the detection rate was improved overall, especially the detection rate more increased when using reflectivity than using vorticity. And the difference of location was reduced to 0.18° on average, increasing the accuracy.

• 통합자연과학논문집
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• 제4권3호
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• pp.229-237
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• 2011

Today they use a weather radar with spatially high resolution in predicting rainfall intensity and utilizing the information for super short-range forecast in order to make predictions of such severe meteorological phenomena as heavy rainfall and snow. For a weather radar, they use the Z-R relation between the reflectivity factor(Z) and rainfall intensity(R) by rainfall particles in the atmosphere in order to estimate intensity. Most used among the various Z-R relation is $Z=200R^{1.6}$ applied to stratiform rain. It's also used to estimate basic rainfall intensity of a weather radar run by the weather center. This study set out to compare rainfall intensity between the reflectivity of a weather radar and the ground rainfall of ASOS(Automatic Surface Observation System) by analyzing many different cases of heavy rain, analyze the errors of different weather radars and identify their problems, and investigate their applicability to nowcasting in case of severe weather.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2002년도 학술발표회 논문집(II)
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• pp.1246-1250
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• 2002

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2003년도 학술발표회논문집(2)
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• pp.723-726
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• 2003

• Journal of information and communication convergence engineering
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• 제4권1호
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• pp.46-52
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• 2006

Precipitation measurement with ground-based radar needs an information of the raindrop size distribution (RSD) characteristics. A 10-month dataset was collected in tropical Atlantic coastal zone of northeastern Brazil where the weather radar was installed. The number of drop was mainly recorded in 300 - 500 drop $mm^{-3}$, of which the maximum was registered around 1.1 mm drop diameter.

• Wind and Structures
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• 제12권4호
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• pp.349-381
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• 2009

Since 1998, several institutions have deployed mobile instrumented towers to collect research-grade meteorological data from landfalling tropical cyclones. This study examines the wind flow characteristics from seven landfalling tropical cyclones using data collected from eight individual mobile tower deployments which occurred from 1998-2005. Gust factor, turbulence intensity, and integral scale statistics are inspected relative to changing surface roughness, mean wind speed and storm-relative position. Radar data, acquired from the National Weather Service (NWS) Weather Surveillance Radar - 1988 Doppler (WSR-88D) network, are examined to explore potential relationships with respect to radar reflectivity and precipitation structure (convective versus stratiform). The results indicate tropical cyclone wind flow characteristics are strongly influenced by the surrounding surface roughness (i.e., exposure) at each observation site, but some secondary storm dependencies are also documented.

• 한국정보통신학회논문지
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• 제4권5호
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• pp.985-996
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• 2000

해안 지역에서 해양으로부터 들어오는 중규모 정도의 강수는 단기 예보를 위하여 원격 탐사에 의한 실시간 관측이 이루어져야 한다. 그러나 위성 관측은 강수를 상세히 묘사하지 못하기 때문에 레이더를 이용한 원거리관측이 요구된다. 본 연구에서는 레이더로 관측된 자료가 강수역을 정확하게 정량화 할 수 있도록 원거리 관측자료의 보정을 논의한다. 반사도의 연직 변화에 기인한 오차는 평균 분포나 통계적 방법으로 그리고 반사도의 감쇠 효과는 반복 편광법으로 보정될 수 있다. 이 같은 다양한 보정을 통하여 레이더로 관측된 원거리 자료를 유용화할 수 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.643-646
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• 2006

An operational calibration is applied to improve radar rainfall intensity using rainfall obtained from rain gauge. The method is applied under the assumption of the temporal continuity of rainfall, the rainfall intensity from rain gauge is linearly related to that from radar. The method is applied to the cases of typhoon and rain band using the reflectivity of CAPPI at 1.5km obtained from Jindo radar. The CAPPI is obtained by bilinear interpolation. For the two cases, the rainfall intensities obtained by operational calibration are very consistent with the ones by the rain gauges. The present study shows that the correlation between the rainfall intensity by operational calibration and rain gauges is better than the one between the rainfall intensity by M-P relationship and rain gauges. The correlation coefficients between the total rainfall intensity obtained by operational calibration and rain gauges in typhoon and rain band cases are 0.99 and 0.97, respectively. Areal rainfalls are estimated using the field of calibration factor interpolated by Barnes objective analysis. The method applied here shows an improvement in the areal rainfall estimation. For the cases of typhoon and rain band, the correlation between the areal rainfall by operational calibration and rain gauges is better than the one between the area rainfall by M-P relationship and rain gauges. The correlation coefficients between the areal rainfall obtained by operational calibration and rain gauges in typhoon and rain band cases are 0.97 and 0.84, respectively. The present study suggests that the operational calibration is very useful for the real-time estimation of rainfall intensity and areal rainfall.

• 한국수자원학회논문집
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• 제53권7호
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• pp.469-480
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• 2020

본 연구는 레이더와 TM간 유역평균강수량 측정의 차이를 2018년 발생한 상당 규모의 호우시 한강과 낙동강의 51개 표준유역을 대상으로 분석하였다. 그 결과 레이더와 TM간의 유역평균강수량 값이 누적강수량은 -65.05~26.09%, 10분최대 강수량은 -82.00~3.80%의 차이가 발생하였다. 이러한 차이를 유역의 특성인 유역면적, 유역평균고도, 유역형상계수 등과 비교하였으나 뚜렷한 상관성을 찾기가 어려웠으며, 지점강수량도 유역평균강수량과 비슷한 경향을 보이는 것을 확인하였다. 따라서 강우형태와 같은 기상학적 조건과의 상관성을 확인하기 위해 고도별 레이더 반사도 값을 분석하였으며 이를 통해 레이더와 TM간 유역평균강수량 측정값의 차이는 유역특성과 같은 지형적 조건 보다는 기상학적 조건과 더 상관성이 있는 것을 확인할 수 있었다.

• 대기
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• 제17권1호
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• pp.69-86
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• 2007

The characteristics of the dual-Doppler wind retrieval method based on a three dimensional variational (3DVAR) conception were investigated from the following four points of view; the sensitivity of the number of iteration, the effect of the weak constraint term, the effect of the smoothness term, and the sensitivity of the error mixing ratio of the radial velocities. In the experiment, the radial velocities relative to the Gosan and Jindo radar sites of the Korea Meteorological Administration (KMA) were calculated from the forecasting of the WRF (Weather Research and Forecast; Skamarock, 2004) model at 1330 UTC 30 June 2006, which is the one and half hour forecast from the initial time, 1200 UTC on that day. The results showed that the retrieval performance of the horizontal wind field was robust, but that of the vertical wind was sensitive to the external conditions, such as iteration number and the on/off of the weak constraint term. The sensitivity of error mixing ratio was so large that even the horizontal wind retrieval efficiency was reduced a lot. But the sensitivity of the smooth term was not so large. When we applied this method to the real mesoscale convective system (MCS) between the Gosan and Jindo radar pair at 1430 UTC 30 June 2006, the wind structure of the convective cells in the MCS was consistently retrieved relative to the reflectivity factor structure. By comparing the vertical wind structure of this case with that of 10 minutes after, 1440 UTC 30 June 2006, we got the physical consistency of our method.