Remote Sensing (Nov 2021)

Accuracy of Copernicus Altimeter Water Level Data in Italian Rivers Accounting for Narrow River Sections

  • Cristina Deidda,
  • Carlo De Michele,
  • Ali Nadir Arslan,
  • Silvano Pecora,
  • Nicolas Taburet

DOI
https://doi.org/10.3390/rs13214456
Journal volume & issue
Vol. 13, no. 21
p. 4456

Abstract

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Information about water level is essential for hydrological monitoring and flood/drought risk assessment. In a large part of Italian river network, in situ instruments for measuring water level are rare or lacking. Here we consider the satellite measurements of water level retrieved by Copernicus altimetric missions (Sentinel 3A, Sentinel 3B, Jason 2/3), and compare these with in situ data, from 19 gauging stations in Italy with a river section in the range of [50, 555] m. The results highlight the potentiality of altimetric satellite measurements for water level retrieval in a case study of Italian rivers. By comparing synchronous satellite and in situ water level difference (i.e., difference between two successive measurements in time of satellite data compared to the difference of two successive measurements in time of in situ data), we found a median value of Pearson correlation of 0.79 and 0.37 m of RMSE. Then, from water level differences, we extracted the satellite water level values with two different procedures: (1) assuming as the initial water level of the satellite measurements the first joint measurement (satellite–in situ data) and (2) calibrating the initial water level, minimizing the mean absolute error metric. The results show the feasibility of using satellite data for water level retrieval in an operative and automatic perspective.

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