Zakharova E.; Nielsen K.; Kamene, G. с соавторами. River discharge estimation from radar altimetry: Assessment of satellite performance, river scales and methods // JOURNAL OF HYDROLOGY v.583

Том: 583     Номер статьи: 124561   Опубликовано: APR 2020

 DOI: 10.1016/j.jhydrol.2020.124561

This work was supported by the European Space Agency ArcFlux project of the Arctic + ITT, by the RFBR project no. No 18-01-00465a and by RFBR project No 18-05-60021-Arctic.

The ENVISAT, Jason-2 and -3, Sentinel-3A, CryoSat-2, and AltiKa satellite altimeters were used to estimate the
discharge of two Arctic rivers: the Ob and Pur in western Siberia. The accuracy of the water height estimates
from ENVISAT varied with river size from 0.63 m for the Ob (~2 km in width) to 1.1 m for the Pur (~0.5 km in
width). A new method for water level estimation combining the CryoSat-2, AltiKa, and Sentinel-3A altimeters
provided better height accuracy (0.49 m for the Ob). The rating curve method of discharge estimation outperforms
the Manning formulation, on the Ob, with a root mean square error (RMSE) of 13% vs 20% for daily
discharge and 1% vs 5% for annual discharge. Sensitivity analysis performed on the Manning formulation
showed high sensitivity to the river depth parameterisation. A functional relationship was identified between the
depth of rivers, in the north of western Siberia, and their widths and deposits types. The combination, for the Ob,
of the rating curve method with the multi-satellite water level retrieval algorithm provided higher discharge
accuracy than previous studies relying on satellite measurements, on numerical modelling or on their combination.
A synthesis of worldwide river altimetry studies supported our finding that the accuracy of altimetric
discharge estimations decreases for narrower rivers. The rating curve method applied to Jason 2/3 height
measurements allows estimation of daily discharges with RMSE of 18% for the wide Ob River but 38% for the
narrow Pur River.