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Estimate Lake Water Levels with Nudging

Source: R/estimate_lake_wlev.R
estimate_lake_wlev.Rd

This function estimates lake water levels using a hydrological model with nudging to observed water levels. It optimizes parameters to minimize the error between simulated and observed levels, applying nudging to guide the simulation towards observed values.

Usage

estimate_lake_wlev(
  data,
  hyps_df,
  model,
  init_elev,
  params = NULL,
  initial_guess = NULL,
  verbose = FALSE
)

Arguments

data

data frame with columns:

  • Date: Date of observation

  • HYD_flow: Inflow to the lake (m3/day)

  • MET_pprain: Precipitation on the lake surface (m/day)

  • evap_m3: Evaporation from the lake surface (m3/day)

  • lvl_obs: Observed lake water level (m)

  • is_obs_lvl: Logical indicating if lvl_obs is an observation (TRUE/FALSE)

hyps_df

data frame with hypsograph data containing columns:

  • elev: Elevation (m)

  • area: Surface area at that elevation (m2)

  • volume: Volume at that elevation (m3)

model

Character string indicating the evaporation model to use:

  • "dy_cd": DYRESM-CAEDYM dynamic evaporation

  • "glm_aed": GLM-AED dynamic evaporation

  • "gotm_wet": GOTM-WET dynamic evaporation

init_elev

Numeric; initial lake elevation (m) to start the simulation. This should be a reasonable estimate based on the observed levels to ensure the optimization converges.

params

Optional named numeric vector c(C, h_inv) of already-fitted outflow parameters (see get_wbal_param). If supplied, the optimisation step is skipped and these values are used directly to generate the final simulated time series. Defaults to NULL, which fits C/h_inv via optim.

initial_guess

Optional initial guess for optimization parameters:

  • C: Outflow coefficient

  • h_inv: Inversion height for outflow calculation

verbose

Logical indicating whether to print optimization details

Value

A data frame with original data and additional columns:

  • lvl_sim: Simulated lake water level (m)

  • HYD_outflow_sim: Simulated lake outflow (m3/day)