earthtide (version 0.0.4)

Earthtide: Earthtide class

Description

Class to generate synthetic earthtide signals.

Format

An R6Class generator object

Usage

et <- Earthtide$new(
  utc = as.POSIXct("2017-01-01", tz = "UTC") + 0:(24 * 7) * 3600, 
  latitude = 52.3868,
  longitude = 9.7144,
  catalog = "ksm04",
  wave_groups = data.frame(start = 0.0, end = 6.0))

et$predict(method = "gravity", astro_update = 1) et$analyze(method = "gravity", astro_update = 1) et$lod_tide() et$pole_tide() et$tide() et$print()

Arguments

• et: An Earthtide object.

• utc: The date-time in UTC (POSIXct vector).

• 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).

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

• ...: Currently not used.

• method: For predict and analyze. One of "gravity", "tidal_potential", "tidal_tilt", "vertical_displacement", "vertical_strain", "areal_strain", "volume_strain", or "ocean_tides".

• astro_update: For predict and analyze. Integer that determines how often to phases are updated in number of samples. Defaults to 1 (every sample), but speed gains are realized with larger values. Typically updating every hour will have speed gains and keep precision (ie 3600 for one second data, 60 for minute data, 1 for hourly data).

Details

$new(utc, latitude, longitude, elevation, azimuth, gravity, earth_radius, earth_eccen, cutoff, wave_groups, catalog, ...) create a new Earthtide object and initialize catalog, station and times.

$predict(method, astro_argument) generate a combined synthetic Earth tide.

$analyze(method, astro_argument) generate components of the Earth tide for analysis.

$lod_tide() generate components of the LOD (Length Of Day) tide.

$pole_tide() generate components of the pole tide.

$tide() get the tide data.frame.

$print() print the Earthtide object.

References

Hartmann, T., Wenzel, H.-G., 1995. The HW95 tidal potential catalogue. Geophys. Res. Lett. 22, 3553<U+2013>3556. 10.1029/95GL03324

Kudryavtsev, S.M., 2004. Improved harmonic development of the Earth tide-generating potential. J. Geod. 77, 829<U+2013>838. 10.1007/s00190-003-0361-2

Wenzel, H.G., 1996. The nanogal software: Earth tide data processing package ETERNA 3.30. Bull. Inf. Mar<U+00E9>es Terrestres, 124, pp.9425-9439. http://www.eas.slu.edu/GGP/ETERNA34/MANUAL/ETERNA33.HTM

Examples

# NOT RUN {
et <- Earthtide$new(
  utc = as.POSIXct("2017-01-01", tz = "UTC") + 0:(24 * 7) * 3600, 
  latitude = 52.3868,
  longitude = 9.7144,
  catalog = "ksm04",
  wave_groups = data.frame(start = 0.0, end = 6.0))

et$predict(method = "gravity", astro_update = 1)

plot(gravity~datetime, et$tide(), type='l')

# }