Evaluation of runoff estimation from GRACE coupled with different meteorological gridded products over the Upper Blue Nile Basin

Alghafli, K., Ali, A. M., Shi, X. , Sloan, W. , Obeid, A. A.A. and Shamsudduha, M. (2023) Evaluation of runoff estimation from GRACE coupled with different meteorological gridded products over the Upper Blue Nile Basin. Journal of Hydrology: Regional Studies, 50, 101545. (doi: 10.1016/j.ejrh.2023.101545)

Abstract

Study Region: The Upper Blue Nile (UBN) basin, Ethiopia. Study Focus: In efforts to accurately close the water balance equation for the UBN basin using remote sensing products, river runoff is calculated as a residual from the water balance equation by incorporating Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage (TWS) and remote sensing products for precipitation (P) and evapotranspiration (ET). The calculated river runoff is then compared to the gauge records located at the basin’s outlet. The best performing combination among the various combinations is chosen by aggregating rankings attributed to both error and linear fit metrics. The errors associated with each satellite product were assessed by forcing the In-Situ runoff to estimate the P, ET, and TWS. This methodology helps in addressing the uncertainty linked with each hydrological component. New Hydrological Insights for the Region: The best P, ET, and TWS combination performance products to estimate runoff are SM2RAIN-CCI, GLEAM, and GRACE Spherical Harmonic products, respectively. The statistical results for the six metrics are R2 = 0.7, slope = 1.6, y-intercept = - 0.5 cm, RMSE = 3 cm, MAE = 2.8 cm, and PBIAS = 36%. The uncertainty from each hydrological component was quantified and showed that improving the accuracy of P and ET estimation is a crucial step to successfully close the water balance.

• Item Type: Articles
• Additional Information: The authors would like to acknowledge the Ministry of Irrigation and Water Resources of Sudan for providing us the discharge data at El Diem.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Shi, Dr John Xiaogang and Alghafli, Khaled Ali Saif Mohammed and Sloan, Professor William
• Authors: Alghafli, K., Ali, A. M., Shi, X., Sloan, W., Obeid, A. A.A., and Shamsudduha, M.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment; College of Social Sciences > School of Social & Environmental Sustainability
• Journal Name: Journal of Hydrology: Regional Studies
• Publisher: Elsevier
• ISSN: 2214-5818
• ISSN (Online): 2214-5818
• Published Online: 10 October 2023
• Copyright Holders: Copyright © 2023 Elsevier E.V.
• First Published: First published in Journal of Hydrology: Regional Studies 50: 101545
• Publisher Policy: Reproduced under a Creative Commons License