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Choose a simulation period from what the data can support

Source: R/summarise_obs.R
suggest_sim_period.Rd

Picks start and stop dates for a simulation by intersecting three things: where the forcing data exist, where the observations to be fitted exist, and how much spin-up is needed before the first comparison.

The forcing constraint is the one most often missed. Observations routinely predate the meteorological record by years, and a period chosen from the observations alone can begin before the model has anything to run on - or leave no room for spin-up, so the first observations are compared against a model still relaxing from its initial condition.

Sparse leading and trailing years are trimmed by min_density, measured in profiles rather than observations, because a depth-resolved calibration is constrained by casts and not by surface grabs. Only the ends are trimmed, so a lean year inside a dense record is kept and the period stays contiguous.

Usage

suggest_sim_period(
  aeme,
  vars_sim = NULL,
  spin_up = NULL,
  min_depths = 3L,
  use_profiles = TRUE,
  min_density = 0.25,
  min_years = 4L,
  align = c("none", "year"),
  year_start_month = 7L
)

Arguments

aeme

Aeme object.

vars_sim

Character. Variables the period must cover. Default NULL uses every observed variable, which is rarely what you want - name the variables you intend to fit.

spin_up

Numeric. Days of spin-up required before start. Default NULL takes the longest spin-up already set on the object.

min_depths

Integer. Distinct depths a visit needs before it counts as a profile. Default 3L.

use_profiles

Logical. Count only profiles when judging coverage. Default TRUE; FALSE counts every sampling date. Variables of kind "scalar" always count by date.

min_density

Numeric. Drop leading and trailing years holding fewer than this fraction of the median year's count. Default 0.25; 0 keeps the record whole.

min_years

Integer. Fewest years a record must span before min_density is applied. Default 4L.

align

Character. "none" (default) starts and stops on observation dates; "year" snaps outward to whole years beginning year_start_month.

year_start_month

Integer. First month of the year used by align = "year". Default 7L, the southern-hemisphere hydrological year, so a period does not split a stratified season in half.

Value

An object of class aeme_sim_period: a list with start, stop, spin_up, spin_up_start, limited_by (what set each end), coverage (per-variable counts inside the chosen period), dropped (years trimmed at each end) and summary (the summarise_obs() result).

See also

summarise_obs(), set_sim_period(), set_time()

Examples

if (FALSE) { # \dontrun{
aeme <- readRDS(system.file("extdata/aeme.rds", package = "AEME"))
p <- suggest_sim_period(aeme, vars_sim = c("HYD_temp", "CHM_oxy"),
                        spin_up = 365)
p
aeme <- set_sim_period(aeme, p)
} # }