DISCHARGE ESTIMATION OF BRANCHED FLOW IN DELTA REGION USING MODIS REFLECTANCE DATA

摘要

Discharge information is a key component in understanding the hydrological regime of delta regions anddeveloping coastal management. Although its importance is recognized, many delta regions collect limiteddischarge data due to the complexity of river flow and the lack of gauging stations. In this study, we investigatedthe potential of using Moderate Resolution Imaging Spectroradiometer (MODIS) reflectancedata to estimate discharge in the branched flow of the Red River Delta (RRD). We extracted data fromMODIS Band 1 (620-670 nm, 250 m resolution) for the location of the in-situ station and applied regressionanalysis to confirm a positive relationship between suspended sediment concentration (SSC) and the reflectanceof the river water surface (R). The regression coefficient β and water balance equations were usedto calculate discharge in the branched flow and then compared to observation data. The results revealed aclose relationship between monthly average SSC and R. Discharge was reasonably simulated with aSpearman’s correlation coefficient of 0.76 at Thuong Cat (TC) by using R as a parameter, with someoverestimation. We discuss possible error sources in this proposed method and their potential effects onestimated results.