Computing and plotting spatialBehaviour products
We can compute the behaviour of winds generated by the topical cyclone Pam (2015) near Vanuatu. First, track data are extracted as follows:
## Warning in checkInputsdefStormsDataset(filename, sep, fields, basin, seasons, : No basin argument specified. StormR will work as expected
## but cannot use basin filtering for speed-up when collecting data## === Loading data ===
## Open database... /private/var/folders/v1/6y176c8d2jz06qr8rd3jq_480000gn/T/RtmpSAC0zx/Rinst11d381788fbb5/StormR/extdata/test_dataset.nc opened
## Collecting data ...
## === DONE ===
Wind profiles
Using track data and the spatialBehaviour() function
with the product="Profiles argument we can generate 2D wind
fields at any time as follows:
## class : SpatRaster
## dimensions : 304, 220, 114 (nrow, ncol, nlyr)
## resolution : 0.04166667, 0.04166667 (x, y)
## extent : 163.6667, 172.8333, -23, -10.33333 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84
## source(s) : memory
## names : PAM_Speed_28, PAM_S~28.33, PAM_S~28.67, PAM_Speed_29, PAM_S~29.33, PAM_S~29.67, ...
## min values : 5.927, 2.302, 3.807, 3.087, 0.848, 2.971, ...
## max values : 61.110, 63.420, 64.483, 64.047, 64.917, 65.017, ...
## time : 2015-03-11 20:00:00 to 2015-03-14 04:00:00 UTCThe function returns a SpatRaster object with two
rasters, one for the wind speed and one for the wind direction, for each
observation or interpolated observation. Rasters’ names follow the
following terminology, the name of the storm in capital letters, “Speed”
or “Direction”, and the index of the observation, separated by
underscores. Note that actual observations have entire indices (e.g.,
41, 42, …) while interpolated observation have decimals (e.g., 41.1,
41.2, …). Most tropical cyclone track data sets are based on
observations gathered every 3 or 6 hours. Therefore, to be able to
compute wind fields every 1 hour, the observations are interpolated.
Wind speed and direction profiles at the 41th observation can be plotted as follows:
Summary statisics
The spatialBehaviour() function can compute the
different products (i.e., "Profiles",
"MSW", "PDI", "Exposure") either
separately or together. Here, we compute all three summary statistics
together as follows:
## class : SpatRaster
## dimensions : 304, 220, 8 (nrow, ncol, nlyr)
## resolution : 0.04166667, 0.04166667 (x, y)
## extent : 163.6667, 172.8333, -23, -10.33333 (xmin, xmax, ymin, ymax)
## coord. ref. : lon/lat WGS 84
## source(s) : memory
## names : PAM_MSW, PAM_PDI, PAM_E~re_18, PAM_E~re_33, PAM_E~re_42, PAM_E~re_49, ...
## min values : 13.7870, 314.4782, 60.00, 60.0000, 60.0000, 60.0000, ...
## max values : 73.9045, 281557.1939, 1854.05, 885.6198, 566.7769, 409.5868, ...The spatialBehaviour() function returns a
SpatRaster object with eight rasters: one for the maximum
sustained wind speed ("MSW"), one for the power dissipation
index ("PDI"), and one for each of the six defaults wind
thresholds values set for the duration of exposure
("Exposure").
## [1] "PAM_MSW" "PAM_PDI" "PAM_Exposure_18" "PAM_Exposure_33"
## [5] "PAM_Exposure_42" "PAM_Exposure_49" "PAM_Exposure_58" "PAM_Exposure_70"By default, the function returns the duration of exposure (in hours)
to wind speeds above the thresholds used by the Saffir-Simpson hurricane
wind scale (i.e., 18, 33, 42, 49, 58, and 70 \(m.s^{-1}\)). This can be change using the
wind_threshold argument.
The maximum sustained wind speed can be plotted as follows:
The power dissipation index can be plotted as follows:
The duration of exposure to wind stronger than 58 \(m.s^{-1}\) (i.e., Saffir-Simpson’s categories 4 and 5) can be plotted as follows:
#### Dynamic plot