Performance Evaluation of Remote Sensing-based High Frequent Streamflow
Estimation Models at the Bramhani River Basin Outlet
Abstract
For catchment-scale streamflow estimation, recently, the preference is
shifting towards the use of innovative remote sensing (RS)-based
approaches at the remote gauging stations. In this context, this study
evaluates the performances of three RS-based models designed with the
near-infrared (NIR) bands of Landsat images at the Jenapur outlet of the
Brahmani River basin in eastern India. These RS-based models are
designed using the spectral behavior of land (C) and water (M) pixels in
the NIR region of the electromagnetic spectrum in the presence and
absence of water surrounding the streamflow gauging station. Further,
the computed pixel ratio (C/M) is used as a parameter for the discharge
estimation, in which four years (2009-2013) of Landsat images are used
during calibration and three years (2014-2016) of these images are used
during validation. Model-I uses the C/M method in which a box-matrix is
conceptualized to analyze the optimal location of the land pixel (C0);
and subsequently, the time series of C/M is calibrated with the in-situ
discharge (Q) time series. The best pixel ratio (C0/M) time series is
preprocessed with an exponential smoothing filter to derive the best
filtered-pixel ratio (C0/M*) time series, which is used in the
regression model to estimate the river discharge. Model-II corresponds
to the multi-pixel ratio (MPR) method, where a 3×3 window is used to
calculate the average reflectance of both the C and M pixels within the
box-matrix, and subsequently, to obtain the best pixel (C0ʹ/Mʹ) ratio as
in the case of Model-I to develop the spectral relationship between
C0ʹ/Mʹ and Q time series. Model-III uses both the C/M and water
width-based function to estimate the streamflow. The performance
evaluation of the models is carried out using the Nash-Sutcliffe
efficiency, Percentage bias, and Mean absolute error, which reveals that
the model performance varies in the order: Model-III >
Model-II > Model-I. This proposed RS-based discharge
estimation model framework has the potential to be used in many world-
rivers with varying cross-sections.