Retrieves Arctic or Antarctic annual Sea Ice Index (in million square km). Source is the National Snow and Ice Data Center, defaults to Arctic (Northern Hemisphere) July sea ice extent. https://nsidc.org/data/seaice_index/archives

get_seaice(
  pole = "N",
  month = "07",
  measure = "extent",
  use_cache = TRUE,
  write_cache = getOption("hs_write_cache")
)

Arguments

pole

'N' for Arctic or 'S' for Antarctic

month

2-digit month to retrieve sea ice for, defaults to '07' (July)

measure

Must be 'extent' or 'area', defaults to 'extent'. Please see terminology link in references for details.

use_cache

(boolean) Return cached data if available, defaults to TRUE. Use FALSE to fetch updated data, or to change pole or month in cache.

write_cache

(boolean) Write data to cache, defaults to FALSE. Use TRUE to write data to cache for later use. Can also be set using options(hs_write_cache=TRUE)

Value

Invisibly returns a tibble with the annual series of monthly Sea Ice Index since 1979 (in million square km).

get_seaice invisibly returns a tibble with annual series of monthly Sea Ice Index since 1979 (in million square km).

User may select Arctic or Antarctic sea ice extent or area (in millions of square kilometers) by year for a given month, specified by argument month. Defaults to Arctic July sea ice extent. https://nsidc.org/arcticseaicenews/faq/#area_extent

References

Author

Hernando Cortina, hch@alum.mit.edu

Examples

# \donttest{ # Fetch sea ice from cache if available: seaice <- get_seaice()
#> Please set use_cache=FALSE if you are changing pole, month, or measure from last cached data.
# # Force cache refresh: seaice <- get_seaice(use_cache = FALSE) # change region and month seaice <- get_seaice(pole='S', month='09', use_cache = FALSE) # # Review cache contents and last update dates: hockeystick_cache_details()
#> <hockeystick cached files> #> directory: C:\Users\hch\AppData\Local/R/cache/R/hockeystick #>
# # Plot output using package's built-in ggplot2 settings plot_seaice(seaice) # }