|Met Office Hadley Centre observations datasets|
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Only sea ice concentrations are available at present.
The SSTs for this data set are not currently available on this website.
The Met Office Hadley Centre's sea ice and sea surface temperature (SST) data set, HadISST, is a unique combination of monthly globally-complete fields of SST and sea ice concentration on a 1 degree latitude-longitude grid from 1850 to date. The latest versions replace the previous version (HadISST1), and the Global sea Ice and Sea Surface Temperature (GISST) data sets.
The field for the month-before-last (see image below) is added to the data set in the first half of every new month.
For a detailed description of HadISST.184.108.40.206 sea ice concentrations and the production process, see the cited paper (in the References box). We recommended you read this before using the data. The lastest version, HadISST.220.127.116.11, contains a number of small improvements/bug fixes compared to HadISST.18.104.22.168. See HadISST versions for more details.
It is worth noting that HadISST.2 data contains monthly mean concentrations, wheras HadISST1 contains monthly medians. It also has a different land/sea (missing data) mask (HadISST.2 contains more ocean/ice grid boxes than HadISST1). See the Data Download page for more information.
Passive microwave data have been combined with historical sources, such as sea ice charts, to create global analyses on a 1 degree grid from 1850 to present. Climatology was often used when no information about the sea ice was available. Bias adjustments were calculated using periods of overlaps between the different data sources used (when possible), and then applied to the concentrations. National Ice Centre charts from 1995 to 2007 were used as a reference to achieve this. A method was developed for estimating the concentrations within the ice pack using the distance from the ice edge. This was used when only the extents were known or when the original concentration fields were heterogeneous.
Overall, HadISST.22.214.171.124 contains more ice than HadISST1, with higher concentrations, shorter marginal ice zones, and larger extents and areas in some regions and periods.
Various figures are produced from the monthly gridded fields.
An animation of the September Arctic sea ice concentration fields for 1979 to present can be found here.
Maintained by: Holly Titchner
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