Analysis of the relationship between GLDAS evapotranspiration and pan evaporation with application to North Korea

Joo-Hun Kim; Dong-Phil Kim; Yong-Soo Cho

doi:10.3741/JKWRA.2026.59.7.703

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2026 Vol.59, Issue 7 Preview Page Next Page

Analysis of the relationship between GLDAS evapotranspiration and pan evaporation with application to North Korea GLDAS 증발산량과 증발접시 자료의 관계 분석 및 북한 지역 적용성 평가

31 July 2026. pp. 703-713

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Abstract

This study quantitatively analyzed the relationship between GLDAS-based evapotranspiration and observed Class A pan evaporation data from the Korea Meteorological Administration, and evaluated the applicability of GLDAS data to North Korea by interpreting the hydrometeorological characteristics of the differences between the two datasets. Daily datasets from 2000 to 2025 were matched for identical periods and dates, and valid datasets were constructed after removing zero values and outliers based on the interquartile range (IQR) method. Regression analysis and statistical evaluations were then performed. The results showed that GLDAS evapotranspiration exhibited an approximately proportional relationship of about 0.68 relative to pan evaporation, with an average correlation coefficient of approximately 0.75. These results indicate that although GLDAS tends to underestimate absolute values, it reasonably reproduces the temporal variability of evapotranspiration. Seasonal analysis revealed underestimation tendencies in spring and winter, whereas relatively higher agreement was observed during summer compared to other seasons. These differences are interpreted as resulting from seasonal variations in energy conditions, including temperature and radiation, as well as water availability associated with precipitation and soil moisture conditions. Spatially, evapotranspiration showed higher values in southern and lowland regions and gradually decreased toward northern and mountainous areas across the Korean Peninsula. In North Korea, relatively smoothed spatial patterns were observed due to the grid-averaging effect associated with the spatial resolution of GLDAS (approximately 0.25°) and limitations in input meteorological data. The results suggest that GLDAS-based evapotranspiration reasonably reproduces the spatiotemporal variability of evapotranspiration and can serve as a useful alternative dataset for hydrometeorological analysis in ungauged regions such as North Korea.

Keywords

GLDAS

Evapotranspiration

Pan evaporation

Spatiotemporal variability

North Korea

Ungauged basin

본 연구에서는 GLDAS 기반 증발산량과 기상청 대형증발접시(Class A pan) 관측자료 간의 관계를 정량적으로 분석하고, 두 자료 간 차이에 대한 수문기상학적 특성을 해석하며 북한 지역에서의 적용 가능성을 평가하였다. 2000년부터 2025년까지의 일자료를 동일 기간 및 날짜 기준으로 매칭하였으며, 0값과 사분위 범위 기반 이상치를 제거한 후 회귀분석 및 통계지표 분석을 수행하였다. 분석 결과, GLDAS 증발산량은 증발접시 증발량 대비 약 0.68 수준의 비례 관계를 나타냈으며 평균 상관계수는 약 0.75로 분석되었다. 이는 GLDAS 자료가 절대값에서는 과소추정 경향을 보이지만 증발산의 시계열 변동 특성은 비교적 잘 재현하고 있음을 의미한다. 계절별 분석 결과, 봄과 겨울에는 과소추정 경향이 나타난 반면 여름철에는 다른 계절에 비해 상대적으로 높은 일치도를 보였다. 이러한 차이는 기온 및 복사에 따른 에너지 조건과 강수 및 토양수분에 의한 수분 공급 조건의 계절적 변화에 기인하는 것으로 해석된다. 또한 한반도 전역에서 증발산은 남부 및 저지대에서 높고 북부 및 산악지역으로 갈수록 감소하는 공간적 경향을 보였다. 북한 지역에서는 GLDAS의 공간해상도(약 0.25°)와 입력자료의 제약에 따른 격자 평균화 효과로 인해 상대적으로 평활한 공간 분포가 나타났다. 본 연구 결과는 GLDAS 기반 증발산 자료가 증발산의 시공간적 변동 특성을 비교적 안정적으로 재현하고 있으며, 북한과 같은 미계측 지역에서 수문·기상 특성 분석을 위한 유용한 대안 자료로 활용 가능함을 시사한다.

키워드

GLDAS

증발산

증발접시

시공간 변동성

북한

미계측 유역

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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 :7
Pages :703-713
Received Date : 2026-03-26
Revised Date : 2026-05-15
Accepted Date : 2026-05-15
DOI :https://doi.org/10.3741/JKWRA.2026.59.7.703

Journal of Korea Water Resources Association ISSN:2799-8746(Print) 2799-8754(Online) 한국수자원학회 논문집

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