calc_earthtide {earthtide}

earthtide

Description

This is a wrapper to the Earthtide R6 class for the prediction of Earth tides. This function is provided for users who would prefer a more typical R function.

Usage

calc_earthtide(
  utc,
  do_predict = TRUE,
  method = "gravity",
  latitude = 0,
  longitude = 0,
  elevation = 0,
  azimuth = 0,
  gravity = 0,
  earth_radius = 6378136.3,
  earth_eccen = 0.0066943979514,
  cutoff = 1e-06,
  wave_groups = NULL,
  catalog = "ksm04",
  eop = NULL,
  return_matrix = FALSE,
  scale = TRUE,
  n_thread = 1L,
  astro_update = 1L,
  ...
)

Arguments

utc

The date-time in UTC (POSIXct vector).

do_predict

run in predict or analyze mode

method

One or more of "gravity", "tidal_potential", "tidal_tilt", "vertical_displacement", "horizontal_displacement", "n_s_displacement", "e_w_displacement", "vertical_strain", "areal_strain", "volume_strain", "horizontal_strain", or "ocean_tides", "pole_tide", "lod_tide". The pole tide and lod_tide are used in predict mode even if do_predict is FALSE. More than one value can only be used if do_predict == TRUE.

latitude

The station latitude (numeric) defaults to 0.

longitude

The station longitude (numeric) defaults to 0.

elevation

The station elevation (m) (numeric) defaults to 0.

azimuth

Earth azimuth (numeric) defaults to 0.

gravity

Gravity at the station (m/s^2) (numeric) 0 to estimate gravity from elevation and latitude.

earth_radius

Radius of earth (m) (numeric) defaults to 6378136.3

earth_eccen

Eccentricity of earth (numeric) defaults to 6.69439795140e-3

cutoff

Cutoff amplitude for constituents (numeric) defaults to 1e-6.

wave_groups

Two column data.frame having start and end of frequency groups (data.frame). This data.frame must have two columns with the names 'start', and 'end' signifying the start and end of the wave groupings. An optional third column 'multiplier' can be provided to scale the particular wave group. If column names do no match, the inferred column positions are start, end, multiplier.

catalog

Use the "hw95s" catalog or "ksm04" catalog (character).

eop

User defined Earth Orientation Parameter (EOP) data.frame with the following columns: datetime, ddt, ut1_utc, lod, x, y, dx, dy

return_matrix

Return a matrix of tidal values instead of data.frame. The datetime column will not be present in this case (logical).

scale

Scale results when do_predict is FALSE

n_thread

Number of threads to use for parallel processing (integer).

astro_update

How often to update astro parameters in number of samples. This speeds up code but may make it slightly less accurate.

...

Currently not used.

Value

data.frame or matrix of tidal results

Examples

tms <- as.POSIXct("1990-01-01", tz = "UTC") + c(0, 3600)
wave_groups <- data.frame(start = 0, end = 8, multiplier = 1.5)

et <- calc_earthtide(
  utc = tms,
  do_predict = TRUE,
  method = c("tidal_potential", "lod_tide", "pole_tide"),
  latitude = 52.3868,
  longitude = 9.7144,
  elevation = 110,
  gravity = 9.8127,
  cutoff = 1.0e-5,
  catalog = "ksm04",
  wave_groups = wave_groups,
  n_thread = 1
)