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HadISST.2.2.1.0 Data: download

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IMPORTANT POINTS TO NOTE

HadISST.2 contains monthly mean sea ice concentrations, whereas HadISST1 contains monthly median concentrations. Monthly means tend to result in slightly larger sea ice extents than medians.

HadISST.2 has a different land/sea (missing data) mask compared to HadISST1. HadISST.2 contains more ocean grid boxes, so ice or open water can be found where HadISST1 has land (missing data). This results in much larger sea ice extents in HadISST.2 for all calendar months, unless the same mask is applied. We recommend that the same grid and mask are used when comparing any sea ice concentration data set.

We will continue to make improvements to HadISST.2 and release new versions, so users should make sure they use the full version number at all times to avoid confusion.

For how to cite the data, please see the References box on the main HadISST.2 page. We recommend that users read Titchner and Rayner (2014) before downloading the sea ice data.

Sea ice concentrations

HadISST.2 SEA ICE CONCENTRATIONS are given as fractions, between 0. and 1., unless otherwise stated. Values greater than 0. and less than 0.15 have been reset as 0 (open water), as described in Titchner and Rayner (2014).

Data are available in NetCDF format. NetCDF files are CF compliant (external link).

HadISST.2.2.0.0_sea_ice_concentration.nc.gz (~54Mb)

Data are also available as a set of compressed plain text files in this data format (given as concentrations multiplied by 100).

HadISST.2.2.1.0_sea_ice_concentration_1850-1870.txt.gz (4.6Mb)
HadISST.2.2.1.0_sea_ice_concentration_1871-1900.txt.gz (6.5Mb)
HadISST.2.2.1.0_sea_ice_concentration_1901-1930.txt.gz (6.3Mb)
HadISST.2.2.1.0_sea_ice_concentration_1931-1960.txt.gz (6.1Mb)
HadISST.2.2.1.0_sea_ice_concentration_1961-1990.txt.gz (6.3Mb)
HadISST.2.2.1.0_sea_ice_concentration_1991-2015.txt.gz (6.5Mb)
HadISST.2.2.1.0_sea_ice_concentration_2016.txt.gz (<1Mb) Contains data for this year up to the most recent available month (typically the month before last).
HadISST.2.2.1.0_sea_ice_concentration_update.txt.gz (~20Kb) Contains the most recent available month's data. Typically the month before last.

Precalculated sea ice extent and area

HadISST.2 has a generous ocean mask (see IMPORTANT POINTS TO NOTE above). We have used a new 1 degree land/sea mask for use in our extent and area calculations, which is also available below.More detials about the mask can be found here.

HadISST.2 SEA ICE EXTENT and AREA are available as plain text files in this data format (given in millions of square kilometers).

WARNING: Other sea ice data sets are likely to contain different land/sea masks. This can significantly affect the values of extent and area, so please take this into consideration during any comparisons. See IMPORTANT POINTS TO NOTE at the top of this page.

HadISST.2.2.1.0_NH_sea_ice_extent.txt - Contains the time series of extents for the Northern Hemisphere
HadISST.2.2.1.0_SH_sea_ice_extent.txt - Contains the time series of extents for the Southern Hemisphere
HadISST.2.2.1.0_NH_sea_ice_area.txt - Contains the time series of area for the Northern Hemisphere
HadISST.2.2.1.0_SH_sea_ice_area.txt - Contains the time series of area for the Southern Hemisphere

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