Computes and regionalizes optimal estimate from multiple discharge timeseries against observed streamflow

Algorithm routes runoff using user specified routing algorithm, for each observation point in sequence starting from the most upstream point. The optimum weight combination is regionalized to the river segments upstream from the optimisation point which do not contain observation information.

optimise_region(
  HS,
  routing = "instant",
  train = 0.5,
  optim_method = "CLS",
  combination = "ts",
  sampling = "random",
  region_type = "upstream",
  no_station = "em",
  drop = TRUE,
  ...,
  verbose = FALSE
)

Arguments

HS	An HS object with observation_ts and runoff_ts
routing	Routing algorithm to use. See accumulate_runoff for options.
train	The share of timeseries used for training period.
optim_method	A character object giving the optimisation method to be used, or a function to be passed to optim. See details.
combination	Whether to do the forecast combination for the entire timeseries, or each month of the year individually, or for full calendar years. Accepts "timeseries", "ts", or "monthly", "mon", or "annual", "ann".
sampling	How to sample training and testing periods. "series" for training serially from beginning, or "random" for a random sample for both training and testing periods.
region_type	How to regionalize combination weights. See details.
no_station	How to handle river segments with no downstream stations. See details.
drop	Drop existing timeseries (columns) in runoff_ts, discharge_ts, or not.
...	Additional parameters passed to the routing algorithm and/or to optimisation..
verbose	Whether or not print progress indicators.

Value

Returns an HS object with routed and optimised discharge_ts, and additional optimisation information in Optimisation_info and Optimised_at.

Details

See optimise_point for help with optimisation options. Note: unlike optimise_point, runoff does not need to be routed in advance, but it is done by the function automatically.

Currently only one regionalization type is implemented: upstream uses the weights obtained for the nearest downstream station for the river segment.

Options for no_station is currently only one: "em", which stands for "ensemble mean". For those river segments with no weights assigned from a station (segments with no downstream observation station), an ensemble mean (each discharge prediction is given equal weight) is computed.