Fast ice data

Source: R/fastice.R

Fast ice data

readfastice(
  date,
  product = c("circum_fast_ice", "binary_fast_ice"),
  xylim = NULL,
  latest = TRUE,
  returnfiles = FALSE,
  ...,
  inputfiles = NULL
)

Arguments

date

date or dates to read (can be character, POSIXt, or Date)

product

'circum_fast_ice' or 'binary_fast_ice'

xylim

extent in native space of the grid

returnfiles

return the file details only

...

reserved for future use, currently ignored

time.resolution

fixed, the underlying time step is 15 days

Value

RasterBrick see Details

Details

High-resolution mapping of circum-Antarctic landfast sea ice distribution, 2000–2018.

Fast ice data on original polar stereographic grid, the product "circum_fast_ice" is 1000m resolution published in Alex Fraser et al. (2020).

Circumpolar product from 2020

Classified surface type:

  • 0: pack ice or ocean

  • 1: continent

  • 2: islands

  • 3: ice shelf

  • 4: fast ice

  • 5: manual fast ice edge

  • 6: auto fast ice edge

Old binary product

  • 0: Southern Ocean, pack ice or icebergs, corresponding to light blue in the PNG files.

  • 1: Antarctic continent (including ice shelves), as defined using the Mosaic of Antarctica product, corresponding to white in the PNG files.

  • 2: Fast ice, as classified from a single 20-day MODIS composite image, corresponding to dark blue in the PNG files

  • 3: Fast ice, as classified using a single 20-day AMSR-E composite image, corresponding to yellow in the PNG files

  • 4: Fast ice, as classified using the previous or next 20-day MODIS composite images, corresponding to red in the PNG files

http://data.aad.gov.au/aadc/metadata/metadata.cfm?entry_id=modis_20day_fast_ice

Examples

## read a particular date, it's circumpolar grid with 7 discrete numerc classes
fice <- readfastice("2015-10-01")
#> Warning: Unknown or uninitialised column: `file`.
#> Error in rep(seq_len(nrow(files)), lengths(time)): invalid 'times' argument
## hone in on Davis
ex <- raster(extent(70.0, 86, -73, -60), crs = "+proj=longlat +datum=WGS84")
davis_ice <- crop(fice, projectExtent(ex, projection(fice)))
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'x' in selecting a method for function 'crop': object 'fice' not found
plot(davis_ice >= 4) #, col = c("brown", "white", grey(c(0.2, 0.5, 0.8))), breaks = c(0, 1, 3, 4, 5, 6))
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'x' in selecting a method for function 'plot': object 'davis_ice' not found

## compare 5 years change
davis_ice2 <- crop(readfastice("2010-10-01"), projectExtent(ex, projection(fice)))
#> Warning: Unknown or uninitialised column: `file`.
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'x' in selecting a method for function 'crop': invalid 'times' argument
par(mfrow = c(2, 1))
plot(davis_ice >= 4)
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'x' in selecting a method for function 'plot': object 'davis_ice' not found
plot(davis_ice2 >= 4) 
#> Error in h(simpleError(msg, call)): error in evaluating the argument 'x' in selecting a method for function 'plot': object 'davis_ice2' not found