Online sea ice data platform: www.seaiceportal.de

There is an increasing public interest in sea ice information from both Polar Regions, which requires up-to-date background information and data sets at different levels for various target groups. In order to serve this interest and need, seaiceportal.de (originally: meereisportal.de) was developed as a comprehensive German knowledge platform on sea ice and its snow cover in the Arctic and Antarctic. It was launched in April 2013. Since then, the content and selection of data sets increased and the data portal received increasing attention, also from the international science community. Meanwhile, we are providing near-real time and archive data of many key parameters of sea ice and its snow cover. The data sets result from measurements acquired by various platforms as well as numerical simulations. Satellite observations of sea ice concentration, freeboard, thickness and drift are available as gridded data sets. Sea ice and snow temperatures and thickness as well as atmospheric parameters are available from autonomous platforms (buoys). Additional ship observations, ice station measurements, and mooring time series are compiled as data collections over the last decade. In parallel, we are continuously extending our meta-data and uncertainty information for all data sets. In addition to the data portal, seaiceportal.de provides general comprehensive background information on sea ice and snow as well as expert statements on recent observations and developments. This content is mostly in German in order to complement the various existing international sites for the German speaking public. We will present the portal, its content and function, but we are also asking for direct user feedback

From the chlorophyll-a in the surface layer to its vertical profile: a Greenland Sea relationship for satellite applications.

Current estimates of global marine primary production range over a factor of two. Improving these estimates requires an accurate knowledge of the chlorophyll vertical profiles, since they are the basis for most primary production models. At high latitudes, the uncertainty in primary production estimates is larger than globally, because here phytoplankton absorption shows specific characteristics due to the low-light adaptation, and in situ data and ocean colour observations are scarce. To date, studies describing the typical chlorophyll profile based on the chlorophyll in the surface layer have not included the Arctic region, or, if it was included, the dependence of the profile shape on surface concentration was neglected. The goal of our study was to derive and describe the typical Greenland Sea chlorophyll profiles, categorized according to the chlorophyll concentration in the surface layer and further monthly resolved profiles. The Greenland Sea was chosen because it is known to be one of the most productive regions of the Arctic and is among the regions in the Arctic where most chlorophyll field data are available. Our database contained 1199 chlorophyll profiles from R/Vs Polarstern and Maria S. Merian cruises combined with data from the ARCSS-PP database (Arctic primary production in situ database) for the years 1957–2010. The profiles were categorized according to their mean concentration in the surface layer, and then monthly median profiles within each category were calculated. The category with the surface layer chlorophyll (CHL) exceeding 0.7 mg C m−3 showed values gradually decreasing from April to August. A similar seasonal pattern was observed when monthly profiles were averaged over all the surface CHL concentrations. The maxima of all chlorophyll profiles moved from the greater depths to the surface from spring to late summer respectively. The profiles with the smallest surface values always showed a subsurface chlorophyll maximum with its median magnitude reaching up to three times the surface concentration. While the variability of the Greenland Sea season in April, May and June followed the global non-monthly resolved relationship of the chlorophyll profile to surface chlorophyll concentrations described by the model of Morel and Berthon (1989), it deviated significantly from the model in the other months (July–September), when the maxima of the chlorophyll are at quite different depths. The Greenland Sea dimensionless monthly median profiles intersected roughly at one common depth within each category. By applying a Gaussian fit with 0.1 mg C m−3 surface chlorophyll steps to the median monthly resolved chlorophyll profiles of the defined categories, mathematical approximations were determined. They generally reproduce the magnitude and position of the CHL maximum, resulting in an average 4% underestimation in Ctot (and 2% in rough primary production estimates) when compared to in situ estimates. These mathematical approximations can be used as the input to the satellite-based primary production models that estimate primary production in the Arctic regions

AMSR-E ASI sea ice concentration data, Antarctic, version 5.4 (NetCDF) (June 2002 - September 2011)

The sea ice concentration product from the University of Bremen, Institute of Environmental Physics (IUP), has been retrieved with the ARTIST Sea Ice (ASI) algorithm, applied to microwave radiometer data of the sensor AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on the NASA satellite Aqua. The data are gridded on a polar stereographic grid (EPSG code 3412, Antarctic) with 6.25 km grid resolution. After the failure of AMSR-E in 2011, the ASI algorithm has been applied to the data of the sensor AMSR2 (Advanced Microwave Scanning Radiometer 2) on the JAXA satellite GCOM-W1 (see the datasets of sea ice concentration from AMSR2). This means that sea ice concentration data have been almost continuously produced since 2002, using AMSR-E data from 2002 until 2011 (this data set), and AMSR2 data since 2012. As several details of the processing chain have changed over the years, in 2018, all ASI ice concentration data for the Arctic and Antarctic based on AMSR-E and AMSR2 have been reprocessed with exactly the same parameters, settings and software. The result are ASI data, version 5.4. The details are explained in the ASI User Guide (https://seaice.uni-bremen.de/fileadmin/user_upload/ASIuserguide.pdf)

AMSR2 ASI sea ice concentration data, Antarctic, version 5.4 (NetCDF) (July 2012 - December 2019)

The sea ice concentration product from the University of Bremen, Institute of Environmental Physics (IUP), is being retrieved with the ARTIST Sea Ice (ASI) algorithm, applied to microwave radiometer data of the sensor AMSR2 (Advanced Microwave Scanning Radiometer 2) on the JAXA satellite GCOM-W1. The data are gridded on a polar stereographic grid (EPSG code 3412, Antarctic) with 6.25 km grid resolution. The ASI algorithm was first implemented at IUP in 2002 for data of the sensor AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on the NASA satellite Aqua (see the dataset of sea ice concentration from AMSR-E). Sea ice concentration data have been continuously produced since then, using AMSR-E data from 2002 until 2011, and AMSR2 data since 2012 (this data set). As several details of the processing chain have changed over the years, in 2018, all ASI ice concentration data for the Arctic and Antarctic based on AMSR-E and AMSR2 have been reprocessed with exactly the same parameters, settings and software. The result are ASI data, version 5.4. The details are explained in the ASI User Guide (https://seaice.uni-bremen.de/fileadmin/user_upload/ASIuserguide.pdf)

AMSR-E ASI sea ice concentration data, Antarctic, version 5.4 (NetCDF) (June 2002 - September 2011)

The sea ice concentration product from the University of Bremen, Institute of Environmental Physics (IUP), has been retrieved with the ARTIST Sea Ice (ASI) algorithm, applied to microwave radiometer data of the sensor AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on the NASA satellite Aqua. The data are gridded on a polar stereographic grid (EPSG code 3412, Antarctic) with 6.25 km grid resolution. After the failure of AMSR-E in 2011, the ASI algorithm has been applied to the data of the sensor AMSR2 (Advanced Microwave Scanning Radiometer 2) on the JAXA satellite GCOM-W1 (see the datasets of sea ice concentration from AMSR2). This means that sea ice concentration data have been almost continuously produced since 2002, using AMSR-E data from 2002 until 2011 (this data set), and AMSR2 data since 2012. As several details of the processing chain have changed over the years, in 2018, all ASI ice concentration data for the Arctic and Antarctic based on AMSR-E and AMSR2 have been reprocessed with exactly the same parameters, settings and software. The result are ASI data, version 5.4. The details are explained in the ASI User Guide (https://seaice.uni-bremen.de/fileadmin/user_upload/ASIuserguide.pdf)

AMSR2 ASI sea ice concentration data, Arctic, version 5.4 (NetCDF) (July 2012 - December 2019)

The sea ice concentration product from the University of Bremen, Institute of Environmental Physics (IUP), is being retrieved with the ARTIST Sea Ice (ASI) algorithm, applied to microwave radiometer data of the sensor AMSR2 (Advanced Microwave Scanning Radiometer 2) on the JAXA satellite GCOM-W1. The data are gridded on a polar stereographic grid (EPSG code 3411, Arctic) with 6.25 km grid resolution. The ASI algorithm was first implemented at IUP in 2002 for data of the sensor AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on the NASA satellite Aqua (see the dataset of sea ice concentration from AMSR-E). Sea ice concentration data have been continuously produced since then, using AMSR-E data from 2002 until 2011, and AMSR2 data since 2012 (this data set). As several details of the processing chain have changed over the years, in 2018, all ASI ice concentration data for the Arctic and Antarctic based on AMSR-E and AMSR2 have been reprocessed with exactly the same parameters, settings and software. The result are ASI data, version 5.4. The details are explained in the ASI User Guide (https://seaice.uni-bremen.de/fileadmin/user_upload/ASIuserguide.pdf)

AMSR-E ASI sea ice concentration data, Arctic, version 5.4 (NetCDF) (June 2002 - September 2011)

The sea ice concentration product from the University of Bremen, Institute of Environmental Physics (IUP), has been retrieved with the ARTIST Sea Ice (ASI) algorithm, applied to microwave radiometer data of the sensor AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on the NASA satellite Aqua. The data are gridded on a polar stereographic grid (EPSG code 3411, Arctic) with 6.25 km grid resolution. After the failure of AMSR-E in 2011, the ASI algorithm has been applied to the data of the sensor AMSR2 (Advanced Microwave Scanning Radiometer 2) on the JAXA satellite GCOM-W1 (see the datasets of sea ice concentration from AMSR2). This means that sea ice concentration data have been almost continuously produced since 2002, using AMSR-E data from 2002 until 2011 (this data set), and AMSR2 data since 2012. As several details of the processing chain have changed over the years, in 2018, all ASI ice concentration data for the Arctic and Antarctic based on AMSR-E and AMSR2 have been reprocessed with exactly the same parameters, settings and software. The result are ASI data, version 5.4. The details are explained in the ASI User Guide (https://seaice.uni-bremen.de/fileadmin/user_upload/ASIuserguide.pdf)

AMSR-E ASI sea ice concentration data, Arctic, version 5.4 (NetCDF) (June 2002 - September 2011)

The sea ice concentration product from the University of Bremen, Institute of Environmental Physics (IUP), has been retrieved with the ARTIST Sea Ice (ASI) algorithm, applied to microwave radiometer data of the sensor AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on the NASA satellite Aqua. The data are gridded on a polar stereographic grid (EPSG code 3411, Arctic) with 6.25 km grid resolution. After the failure of AMSR-E in 2011, the ASI algorithm has been applied to the data of the sensor AMSR2 (Advanced Microwave Scanning Radiometer 2) on the JAXA satellite GCOM-W1 (see the datasets of sea ice concentration from AMSR2). This means that sea ice concentration data have been almost continuously produced since 2002, using AMSR-E data from 2002 until 2011 (this data set), and AMSR2 data since 2012. As several details of the processing chain have changed over the years, in 2018, all ASI ice concentration data for the Arctic and Antarctic based on AMSR-E and AMSR2 have been reprocessed with exactly the same parameters, settings and software. The result are ASI data, version 5.4. The details are explained in the ASI User Guide (https://seaice.uni-bremen.de/fileadmin/user_upload/ASIuserguide.pdf)

AMSR-2 winter snow depth on Arctic sea ice, Version 1.0 (NetCDF) (2012 to 2018)

The AMSR-2 snow depth on Arctic sea ice product contains daily gridded snow depth data for the period from 2012 to 2018 (see also: AMSR-E snow depth on Arctic sea ice product (2002 to 2011), doi:10.1594/PANGAEA.902748). The product is based on an empirical algorithm using passive microwave satellite observations from the AMSR-2 (Advanced Microwave Scanning Radiometer 2) sensors on the JAXA satellite GCOM-W1, gridded on a polar stereographic grid (EPSG code 3411, Arctic) with 25 km grid resolution. Over seasonal ice, the snow depth is available from November to April. Over Arctic multiyea ice (ice that has survived at least one summer melt) the snow depth is available in March and April. Details about the algorithm are described in Rostosky et al. (2018). More details about the data product can be found in the product manual (https://seaice.uni-bremen.de/data/amsr2/SnowDepth/