Sea ice concentration distribution derived with the ASI algorithm from AMSR-E data in the northern (left) and southern (right) hemisphere for Sep. 27, 2011. Due to a malfunction of the antenna of the AMSR-E instrument there will be no further sea ice concentration maps available in the near future.
But: On http://www.seaice.de and https://seaice.uni-bremen.de/sea-ice-concentration-amsr-eamsr2 you can find near-real-time daily sea ice concentration maps derived from AMSR2 data using the ASI algorithm.
RESTRICTED only accessable in CEN/MPI network or via CliSAP login What does that mean?
Data access via file system: /data/icdc/ice_and_snow/asi_amsre_iceconc
Advanced Microwave Scanning Radiometer aboard EOS (AMSR-E) data have been used to produce a finer resolved sea-ice concentration data set gridded onto a polar-stereographic grid true at 70 degrees with 6.25 km grid resolution. The sea-ice concentration data available here have been computed by applying the ARTIST Sea Ice (ASI) algorithm to brightness temperatures measured with the 89 GHz AMSR-E channels. These channels have a considereably finer spatial resolution than the commonly used lower frequency channels.
So far there are no estimates of the uncertainties included in the data product.
|Sea ice concentration||0-100%|
Period and temporal resolution:
- June 19, 2002, to September 30, 2011
Coverage and spatial resolution:
- Northern and Southern hemisphere
- Spatial resolution: 6.25 km x 6.25 km, polar-stereographic grid from NSIDC, tangential plane at 70°N and 70°S, respectively
- Geographic longitude: 0°E to 360°E
- Geographic latitude: from about 41°N and 41°S to 90°N and 90°S, respectively, in the corners of the grid further equatorward
- Dimensions: 1216 columns x 1792 rows (Northern hemisphere), 1264 columns x 1328 rows (Southern hemisphere)
- Altitude: 0.0 m
The data set does not yet contain uncertainty estimates.
A number of comparisons with ship observations and independent satellite data (see publications listed below) have proven the skill of the ASI algorithm in particular for high sea-ice concentrations.
In addition a theoretical investigation about uncertainties that are expected due to sensor noise and/or varying surface and environmental conditions has been made; its results can be found in Spreen et al. (2008).
We note, that the advantage given with the finer spatial resolution could be offset sometimes by the higher uncertainty of the retrieved sea-ice concentration. This is caused by the higher sensitivity of the 89 GHz channels to the atmospheric water vapor content and the cloud liquid water content when compared to the usually used 37 GHz and 19 GHz channels. In particular in the marginal ice zone sea-ice concentration could therefore exhibit a positive bias.
Alfred Wegener Institute for Polar and Marine Research (AWI) / Bremerhaven
email: lars.kaleschke (at) awi.de
ICDC / CEN / University of Hamburg
email: stefan.kern (at) uni-hamburg.de
Institute of Environmental Physics / University of Bremen
email: gunnar.spreen (at) uni-bremen.de
- Kaleschke, L., et al., 2001, SSM/I sea ice remote sensing for meoscale ocean-atmosphere interaction analysis. Canad. J. Rem. Sens., 27, 526-537.
- Kern, S., et al., 2003, A comparison of two 85-GHz SSM/I sea ice concentration algorithms with AVHRR and ERS-2 SAR imagery. Trans. Geosci. Rem. Sens., 41-10, 2294-2306.
- Andersen, S., et al., 2006, Improved retrieval of sea ice total concentration from spaceborne passive microwave observations using numerical weather prediction model fields: An intercomparison of nine algorithms. Rem. Sens. Environ., 104-4, 374-392.
- Andersen, S., et al., 2007, Intercomparison of passive microwave sea ice concentration retrievals over the high-concentration Arctic sea ice. J. Geophys. Res., 112, C08004, doi:10.1029/2006JC003543.
- Spreen, G., et al., 2008, Sea ice remote sensing using AMSR-E 89-GHz channels. J. Geophys. Res., 113, C02S03, doi:10.1029/2005JC003384.
- Wiebe, H., et al., 2009, Comparison of the ASI ice concentration algorithm with Landsat-7 ETM+ and SAR imagery. Trans. Geosci. Rem. Sens., 47-9, 3008-3015.
Please cite as
"ASI Algorithm AMSR-E sea ice concentration were obtained for [PERIOD] from the Integrated Climate Date Center (ICDC, icdc.cen.uni-hamburg.de/), University of Hamburg, Hamburg, Germany"