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2026 Vol.59, Issue 8 Preview Page
Comparison and accuracy assessment of river water levels derived from ICESat-2 and SWOT in the Nakdong River

ICESat-2 및 SWOT 기반 하천 수위의 비교 및 정확도 평가: 낙동강 달성보 구간을 중심으로

Seogyeong Leea
,
Suin Choib*
,
Dongsu Kimc
,
Kyeongdong Kimd
이 서경a
,
최 수인b*
,
김 동수c
,
김 경동d
aPh.D. Course, Department of Civil & Environmental Engineering, Dankook University, Yongin, Korea
bPh.D. Course, Department of Civil & Environmental Engineering, Dankook University, Yongin, Korea
cProfessor, Department of Civil Engineering, Dankook University, Yongin, Korea
dPostdoctoral Researcher, IHR-Hydroscience & Engineering, University of Iowa, Iowa City, Iowa, USA
a단국대학교 인프라건설공학과 박사과정
b단국대학교 인프라건설공학과 박사과정
c단국대학교 인프라건설공학과 교수
d아이오와대학교 박사 후 연구원
*Corresponding Author
31 August 2026. pp. 947-956
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Abstract

This study evaluates the accuracy of satellite-based river water level monitoring using ICESat-2 and SWOT data in the Dalseong Weir reach of the Nakdong River, South Korea. Water surface elevation (WSE) was extracted from ICESat-2 inland water products (ATL13) and compared with in-situ water level gauge observations to quantitatively assess the reliability of satellite-derived water levels. Accuracy was evaluated using statistical metrics including root mean square error (RMSE), mean absolute error (MAE), and bias, together with cumulative distribution functions (CDFs) of absolute errors. The results indicate that ICESat-2 water levels show good agreement with ground-based observations, with most differences falling within the decimeter range. These findings demonstrate that ICESat-2 provides reliable water level measurements in Korean river environments. In addition, SWOT water level data acquired over the same area were analyzed to compare the observational characteristics and potential applications of the two satellite systems. SWOT data were extracted at locations corresponding to ICESat-2 footprints to ensure spatial consistency in the comparison. This approach enables a consistent comparison between point-based high-precision measurements from ICESat-2 and spatially distributed two-dimensional observations from SWOT. This study provides a case-based validation of satellite-derived river water levels in Korea and demonstrates the practical applicability of integrating satellite observations into river monitoring systems. The findings contribute to expanding satellite-based water level monitoring to ungauged river reaches and diverse hydrological conditions.

Keywords
ICESat-2
SWOT satellite
River water level
Water Surface Elevation (WSE)
Satellite hydrology
Accuracy assessment

본 연구는 위성 레이저 고도계 ICESat-2와 레이더 간섭계 기반 SWOT 위성 자료를 활용하여 낙동강 수계 달성보 구간에서의 하천 수위 모니터링 정확도를 평가하였다. ICESat-2에서 제공하는 내륙 수면 고도 산출물(ATL13)을 이용하여 하천 수면고도(WSE)를 추출하고, 이를 지상 수위계 관측자료와 비교하여 위성 수위 자료의 신뢰도를 정량적으로 검증하였다. 정확도 평가는 RMSE, 평균절대오차(MAE), 편향(bias) 등의 통계 지표와 함께 절대 오차 누적분포함수(CDF) 분석을 통해 수행하였다. 분석 결과, ICESat-2 수위 자료는 달성보 구간에서 지상 수위계 관측값과 전반적으로 양호한 일치도를 보였으며, 대부분의 관측값이 데시미터 이내의 오차 범위에 포함되는 것으로 나타났다. 이는 ICESat-2 수위 자료가 국내 하천 환경에서도 안정적인 정확도를 확보할 수 있음을 시사한다. 또한 동일 지역에서 획득된 SWOT 수위 자료를 함께 분석하여 두 위성의 관측 특성과 활용 가능성을 비교하였다. SWOT 자료는 ICESat-2 관측 위치와 대응되는 픽셀을 기준으로 추출하여 공간적 일관성을 확보하였으며, 이를 통해 점 기반 고정밀 관측을 수행하는 ICESat-2와 2차원 수면고도 분포를 제공하는 SWOT 간의 구조적 차이를 명확히 비교하였다. 본 연구는 국내 하천을 대상으로 위성 기반 수위 자료의 정확도를 지상 관측자료와 체계적으로 검증한 사례로서, 향후 수위계가 설치되지 않은 하천 구간이나 다양한 수문 환경으로 위성 기반 하천 수위 모니터링을 확장 적용하기 위한 기초 자료를 제공한다.

키워드
ICESat-2
SWOT 위성
하천 수위
수면고도(WSE)
위성 수문 관측
정확도 평가
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Information
  • Publisher :KOREA WATER RESOURECES ASSOCIATION
  • Publisher(Ko) :한국수자원학회
  • Journal Title :Journal of Korea Water Resources Association
  • Journal Title(Ko) :한국수자원학회 논문집
  • Volume : 59
  • No :8
  • Pages :947-956
  • Received Date : 2026-04-03
  • Revised Date : 2026-05-01
  • Accepted Date : 2026-06-01
  • DOI :https://doi.org/10.3741/JKWRA.2026.59.8.947
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