Kalman filtering
SNOW-43 is a state-space version of the Snow Accumulation and Ablation model (Hydro-17) with the option of performing Kalman filtering updating.
The state-space formulation and Kalman filtering implementation are described in Hydro-43.
The Kalman filter accounts for the relative uncertainties of observed and simulated water equivalent values in a procedure that optimally updates the model simulated states using areal estimates of snow water equivalent based on observations.
Of course, other rainfall/runoff models are available in NWSRFS.
However, the Sacramento Soil Moisture Accounting Model, the Continuous API Model, and the Snow Model are the most commonly used.
Additional information on other models is available from the Hydrologic Research Laboratory of the NWS referenced at the end of this material.
