https://doi.org/10.1029/2022WR034294

Knoben, W. J. M., Clark, M. P. (2022) Comment on “the treatment of uncertainty in hydrometric observations: A probabilistic description of streamflow records” by de Oliveira and Vrugt, Water Resources Research, 60, e2022WR034294

Quantifying uncertainties and errors in hydrometric observations is critical to improve our ability to predict streamflow. de Oliveira and Vrugt (2022, https://doi.org/10.1029/2022wr032263 ) expand on an earlier publication (Vrugt et al., 2005, https://doi.org/10.1029/2004wr003059 ) to describe a difference-based variance estimation method that is, used to estimate the aleatory observation uncertainty in streamflow records directly from a time series of such data. The method is then applied to hourly data from 500+ catchments across the contiguous United States. This comment outlines our concerns that the assumptions needed to effectively use difference-based variance estimation methods are not always met by hourly streamflow records. We illustrate our concerns through the use of a specific test case. We argue that more work is needed to quantify the individual sources of errors and uncertainties in hydrometric observations.