Technical Note: Data assimilation and autoregression for using near-real-time streamflow observations in long short-term memory networks

Daniel Klotz
Jonathan Frame
Martin Gauch
Frederik Kratzert
Alden Keefe Sampson
Guy Shalev
Sella Nevo
Hydrology and Earth System Science (2022)

Abstract

Ingesting near-real-time observation data is a critical component of many operational hydrological forecasting systems. In this paper we compare two strategies for ingesting near-real-time streamflow observations into Long Short-Term Memory (LSTM) rainfall-runoff models: autoregression (a forward method) and variational data assimilation. Autoregression is both more accurate and more computationally efficient than data assimilation. Autoregression is sensitive to missing data, however an appropriate (and simple) training strategy mitigates this problem.