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The analysis of differences of mean basin precipitation between TM and radar using correlation with basin characteristics and rainfall patterns

TM과 레이더를 이용한 유역평균강수량 차이와 유역특성 및 강우형태와의 상관성

  • Received : 2020.03.22
  • Accepted : 2020.05.13
  • Published : 2020.07.31

Abstract

This study analyzed the differences of mean basin precipitation between TM and radar based on the 51 standard basins in Han river and Nakdong river when large scale of heavy rains occurred in 2018. The result shows that the differences between radar and TM are -65.05 ~ 26.09% and -82.00 ~ 3.80% for accumulated and 10 min. maximum mean basin precipitation, respectively. The correlation analysis between the differences of estimated mean basin precipitation and basin characteristics such as average altitude of basin, area of basin, and shape factor of basin presents that there is no clear correlation between them. And the differences of point precipitation also shows the similar tendency with those of mean basin precipitation. In order to find out the correlation between them and meteorological conditions such as rainfall patterns, the reflectivity of radars according to the observation angles is analyzed at the selected basins, and then it is found that the differences of mean basin precipitation between TM and radar is more dominated by the meteorological conditions than by the topographic conditions such as basin characteristics.

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.

Keywords

References

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