The main user groups for the sea ice climate data sets are: 

(1) Sea ice and climate research

(2) Model development and validation

(3) Sea ice monitoring and forecasting services

(4) Marine transportation in polar and sub-polar regions

(5) Oil and gas exploration in polar regions

(6) Marine ecosystems and fisheries

During Phase 1 (2011-2014) A user workshop was organised by University of Hamburg 18-19 September 2014 During Phase 2 (2015-2018) A second user workshop was organised in Hamburg 9 - 11 October 2017.      

The conclusion of the user requirments for sea ice climate data are: 

 Systematic and long-term observations of the major sea ice variables is only possible using past and present satellite Earth Observation (EO) data. Sea ice data from satellites has been collected for more than four decades and sea ice mapping is one of the most successful applications of EO data in climate change studies. Several sensors and retrieval methods have been developed and successfully utilized to measure sea ice area, concentration and drift [e.g. Breivik et al., 2009]. There are also other sea ice parameters of importance for climate research such as thickness, albedo, snow cover, melt ponds and leads/polynyas. [e.g. GCOS, 2010; IGOS, 2007]. Satellite remote sensing can contribute to retrieving quantitative measurements of most of these variables, although long timeseries covering several decades only exist for some of the variables. 

Several studies have been focused on the requirements from space agencies to develop and launch satellites that can observe many atmospheric and ocean/sea ice variables to support modeling and forecasting. Sea ice is described very generally in these studies. A more comprehensive requirement reports was provided by the IGOS Cryospheric Theme report (IGOS, 2007) where the observational requirements for many sea ice variables are specified. The requirements are defined in terms of spatial and temporal resolution and sampling, measurement range and accuracy, delay time and performance limits for each variable. The requirements are also divided into

(1) operational requirements, implying that data are needed daily in near-real time in order to be used in monitoring and short-term forecasting, and

(2) seasonal and long-term observations for climate research requirements, which require long time series with high accuracy based on merging of data from several satellites.

The climate research requirements for sea ice variables were reiterated in the CGOS report no 154 from 2011 (GCOS, 2011) where specifications were given for sea ice concentration, extent/edge, thickness and drift. These are summarized as follows:

·    SI concentration (SIC): Target requirements are 10 – 15 km horizontal resolution, weekly temporal resolution, and measurement accuracy: 5 km.

·    SI extent/edge: Target requirements are 1 – 5 km horizontal resolution, weekly temporal resolution, and measurement accuracy: 5 km

·       SI thickness (SIT): Target requirements are 25 km in horizontal resolution, > 0.05 m in vertical resolution, monthly temporal resolution, and measurement accuracy: 0.10 m.

·       SI drift: Target requirements are 1 km in horizontal resolution, weekly temporal resolution, and measurement accuracy: 1 km per day.

The Target requirements are set by GCOS in order to resolve interannual variations and trends in each of the variables.

The main application areas and user groups for sea ice climate data are described. They range from climate research activities to marine biology and ecosystems research, management of marine resources, sea transportation, offshore exploration, design and construction of vessels and platforms, impact on indigenous people, insurance, governance and policy making. In the CCI Sea Ice project, a user survey was conducted among 91 institutions from different user groups (Sandven et al., 2012). This survey provided useful statistics on specific requirements with focus on the four GCOS variables, described above. The survey documented that long time series of covering several decades with accurate data is the most important requirement. For sea ice concentration and extent this is mainly fulfilled, but for sea ice thickness and drift the measurements are not yet fulfilling the requirements.

More information is available in the User Requirement document (D1.1: URD), which has been prepared and updated during the project period. The document is available under "Documents".