• The 12.5 km sea ice concentration product is generated using two algorithms: the enhanced NASA Team (NT2) algorithm (Markus and Cavalieri 2000) for the Arctic and the Bootstrap Basic Algorithm (BBA, Comiso 1995) for the Antarctic.
• The method for deriving snow depth from SSM/I data is described in Markus and Cavalieri (1998).

• The 25 km sea ice product is generated using two algorithms: the enhanced NASA Team (NT2) algorithm (Markus and Cavalieri 2000) in the Arctic and the AMSR Bootstrap Algorithm (ABA; Comiso, Cavalieri, and Markus 2003) in the Antarctic.
• The AMSR Bootstrap Algorithm (ABA; Comiso, Cavalieri, and Markus 2003) that makes use of the 6.9 GHz data to reduce temperature effects on V1937 data provides very similar results to those of the BBA algorithm used in the 12.5 km sea ice product, indicating that errors associated with temperature effects on the latter are relatively minor; however, ABA allows for the calculation of ice temperature, which in itself is an important climate parameter.

• Continuous time series of daily averaged total ice concentrations derived from a modified version of the Bootstrap algorithm, which uses revised tie-points to provide more temporally consistent data between the various sensors (SMMR , F8, F11, and F13)
• Fewer false ice concentrations from weather effects in the open ocean and along land/ocean boundaries than with the standard algorithm
• Missing data, including small gaps in the time series, are temporally and spatially interpolated.
• Updated about once a year
• Especially useful for long time series analysis of ice extent

• Level 2 data. Users have access to all orbits rather than 24-hour averages.
• Only total ice is calculated for the Southern Hemisphere.

(links to browse directories on our ftp site)

• Daily averaged total sea ice concentrations for the Arctic and the Antarctic
• Standard algorithm weather filter removes most false ice concentrations over open ocean that result from atmospheric effects.
• Land contamination effects not eliminated
• Updated approximately quarterly

• The Meltpond2000 project was the first in a series of Arctic and Antarctic aircraft campaigns to validate sea ice algorithms developed for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E), primarily to quantify errors in AMSR-E sea ice products resulting from the presence of melt ponds. The objective was to compare sea ice concentrations derived from AMSR-E algorithms but using Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) radiances, with coincident observations from aircraft sensors and high-resolution satellite imagery.

• These data cover the period during which the standard sea ice data are being processed by Remote Sensing Systems, Inc. and are not available for distribution. This is typically three to six months before the present.
• Typically available within 1-2 days following the time of SSM/I image acquisition
• More recent coverage than is available from the standard sea ice data set
• Derived from brightness temperatures that have not received the same types of quality control applied to the standard sea ice data set
• Users wanting to detail trends in sea ice concentration and extent should exercise caution with these data, and are encouraged to use the other standard sea ice products when near-real time coverage is not an issue.

(links to registration form to access data and browse imagery)

• Typically available within 1-2 days following the time of SSM/I image acquisition
• Derived from brightness temperatures that have not received the same types of quality control that are applied to the standard sea ice data set
• Developed to assist in generation of EOS satellite products that require knowledge of snow and ice coverage
• Data are useful for near real-time investigations of changes in sea ice concentration in conjunction with variations in snow cover.
• Masks are applied to minimize erroneous retrievals of sea ice over open ocean and along coastlines.
• Users wanting to detail trends in sea ice concentration and extent should exercise caution with these data, and are encouraged to use the other standard sea ice products when near-real time coverage is not an issue.

• Includes monthly, multiyear monthly, and yearly sea ice concentration grids generated from ESMR data
• Since ESMR provided only one spectral channel, a different algorithm was used to derive ice concentrations compared to the algorithms used for SMMR and SSM/I-derived products.
• ESMR provides additional detail and coverage to augment other data sets.
• ESMR data show variations within the interior portions of the ice pack. Such regions are not typically mapped in detail in ice charts.

• Includes gridded brightness temperatures and ice concentrations for all SMMR channels
• SMMR provides two lower-frequency channels at 6.6 GHz and 10.78 GHz, but lacks SSM/I's 85 GHz channel.
• Lower-frequency channels are not used in the NASA Team algorithm, but they provide additional information on surface conditions that can be used for studies of surface temperature and variations in ice type.

• Snow cover extent is based on the digital NOAA-NESDIS Weekly Northern Hemisphere Snow Charts, revised by D. Robinson (Rutgers University) and regridded to the EASE-Grid.
• Original NOAA-NESDIS weekly snow charts are derived from the manual interpretation of AVHRR, GOES, and other visible-band satellite data.
• Sea ice extent is based on the NSIDC polar stereographic sea ice concentration grids derived from SMMR and SSM/I passive microwave brightness temperature data.
• This data set was designed to represent large-scale seasonal fluctuations in snow cover and sea ice extent, and is most appropriate for large area studies.

• Daily and monthly sea ice concentrations for the Arctic and Antarctic
• Modified calibration coefficients designed to provide a consistent sea ice record
• Additional weather filtering to remove remaining false ice concentrations not eliminated using the standard algorithm weather filter
• Methods to reduce land contamination effects
• Missing data, including small gaps in the time series, are temporally and spatially interpolated.
• Useful for long time series analysis of ice extent

• The Sea Ice Index consists of graphics showing trends and anomalies in monthly mean Arctic and Antarctic sea ice concentration and extent, with a table of monthly mean extent in millions of square km.
• This product is intended to help researchers illustrate sea ice conditions, and to inform users with general questions about recent ice concentration and extent.
• Advantages include monthly updates, and interactive plotting and image production.