Name: Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations, Version 2
Creator: National Snow and Ice Data Center
Keywords: SEA ICE CONCENTRATION

Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations, Version 2

Data set id:

NSIDC-0081

DOI: 10.5067/YTTHO2FJQ97K

Data Citation and Acknowledgment
As a condition of using these data, you must cite the use of this data set. Such a practice gives credit to data set producers and advances principles of transparency and reproducibility.

Meier, W. N., Stewart, J. S., Wilcox, H., Hardman, M. A. & Scott, D. J. (2021). Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations. (NSIDC-0081, Version 2). [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/YTTHO2FJQ97K. [describe subset used if applicable]. Date Accessed 07-03-2026.

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This data set has been retired.
Version Summary

Version update reflects the conversion of the data set from binary to netCDF.

Overview

This data set provides a Near-Real-Time (NRT) map of sea ice concentrations for both the Northern and Southern Hemispheres. As of 18 June 2026, this data set is retired and no longer available for download. Forward processing for this product ceased in January 2026. We recommend using the research quality AMSR2 Daily Polar Gridded Sea Ice Concentrations (https://doi.org/10.5067/W13AO54SS7CW) or Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data (https://doi.org/10.5067/MPYG15WAA4WX) data sets as an alternative.

Parameter(s):

SEA ICE CONCENTRATION

Platform(s):

DMSP 5D-3/F16

DMSP 5D-3/F17

DMSP 5D-3/F18

Sensor(s):

SSMIS

Data Format(s):

PNG

netCDF-4

Temporal Coverage:

1 January 2024 to 14 January 2026

Temporal Resolution:

1 day

Spatial Resolution:

25 km

25 km

Spatial Reference System(s):

NSIDC Sea Ice Polar Stereographic North
EPSG:3411
NSIDC Sea Ice Polar Stereographic South
EPSG:3412

Spatial Coverage:

Northern latitude
90
Southern latitude
30.98
Eastern longitude
180
Western longitude
-180
Northern latitude
-39.23
Southern latitude
-90
Eastern longitude
180
Western longitude
-180

Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

View Metadata Record

Strengths and Limitations

Strengths

Useful for large-scale monitoring of sea ice
Microwave observations provide surface snow and ice coverage during cloudy and night-time (including polar night) conditions (Cavalieri et al., 1999)
Thorough inter-calibration between sensors for consistency throughout the record (Cavalieri et al., 1999; Cavalieri et al., 2012)
Less sensitive to temperature variations because it uses ratios instead of differences (Comiso et al., 1997)
Concentrations are generally reliable within the ice pack (away from the ice edge) during cold (non-melt) conditions (Comiso et al., 1997)
Useful input/validation of climate model simulations (National Center for Atmospheric Research Staff, 2017)

Limitations

Low spatial resolution (25 km gridded) limits detail on concentration and precision of sea ice edge; is unsuitable for operational/navigational support (Cavalieri et al., 1999)
Underestimates sea ice concentration during melt season (Kern et al., 2020) and/or when the ice is thin (Ivanova et al., 2015)
Higher uncertainties in Antarctica due to flooded snow and other ice characteristics (Comiso et al., 1997)
Algorithm coefficients are fixed for a given sensor, so biases can occur if characteristic surface conditions change (Cavalieri et al., 1999)
False coastal ice can occur due to mixed land and ocean within a sensor footprint (Cavalieri et al., 1999)
Near-real-time product with no planned reprocessing for long-term consistency; should not be used to derive long-term trends in sea ice or snow (Cavalieri et al., 1999)

Data Access & Tools

This data set has been retired. Please contact user services if you have questions.

Documentation

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