Author(s): Yeji Son; Chaelim Lee; Sangdan Kim
Linked Author(s):
Keywords: Copula; Influencing factors; Low flow condition; River water temperature; Sensitivity analysis
Abstract: River water temperature is shaped by interactions among climate, streamflow, river morphology, and human activities. Under low-flow conditions, reduced heat capacity accelerates warming, placing stress on aquatic ecosystems and water use. However, studies examining the temperature–flow relationship through a dependence-structure framework remain limited. This study compiled monthly water temperature and discharge data for major basins in South Korea and constructed a bivariate joint dependence structure using optimal marginal distributions and Copula models. High-temperature exceedance probabilities under low-flow conditions were estimated, and sensitivity was calculated for each basin and month. To identify the major factors governing the occurrence of positive sensitivity, continuous sensitivity values were regressed against meteorological variables, vegetation indices, watershed topography, and land-cover characteristics. This Copula-based framework improves the assessment of river thermal vulnerability during low-flow periods and provides essential insights to support river temperature management and decision-making.
Year: 2026