Download the 1D spectrum data from IFREMER ftp

Usage

get_1d_spectrum(point, start = "1994-01-01", end = "1994-02-28")

Arguments

point: the location name (string) requested. Alternatively, the node number. The consistency is checked internally.
start: the starting date (as a string). The consistency is checked internally.
end: the ending date as a string

Value

A list with 12 elements:

longitude

Longitude

latitude

Latitude

frequency1

Lower frequency

frequency2

Upper frequency

ef

Surface elevation variance spectral density

th1m

Mean direction from first spectral moment

th2m

Mean direction from second spectral moment

sth1m

Mean directional spreading from first spectral moment

sth2m

Mean directional spreading from second spectral moment

freq

Central frequency

forcings

A data.frame with 14 variables:

time: Time
dpt: Depth, positive downward
wnd: Wind intensity, at 10m above sea level
wnddir: Wind direction, comes from
cur: Current intensity, at the surface
curdir: Current direction, going to
hs: Significant wave height
fp: Peak wave frequency
f02: Mean wave frequency
f0m1: Mean wave frequency at spectral moment minus one
th1p: Mean wave direction at spectral peak
sth1p: Directional spreading at spectral peak
dir: Mean wave direction
spr: Mean directional spreading

station

Station name

Examples

spec1D <- get_1d_spectrum("SEMREVO", start = "1994-01-01", end = "1994-02-28")
r <- as.POSIXct(round(range(spec1D$forcings$time), "month"))
image(spec1D$forcings$time, spec1D$freq, t(spec1D$ef),
  xaxt = "n", xlab = "Time",
  ylab = "Frequency (Hz)"
)
axis.POSIXct(1, spec1D$forcings$time,
  at = seq(r[1], r[2], by = "week"),
  format = "%Y-%m-%d", las = 2
)