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Data Set ID:
NSIDC-0747

Arctic Sea Ice Seasonal Change and Melt/Freeze Climate Indicators from Satellite Data, Version 1

The product contains melt-season indicators that can be used to delineate various stages in the summer melt and freeze-up period of sea ice. The data were primarily derived using Sea Ice Concentration (SIC) observations from the NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration and brightness temperature observations from the DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures; both input data sets are archived at NSIDC. The main parameters for this data set include the dates of melt onset, early melt onset, and continuous melt onset; dates of early and continuous freeze onset; day of opening (last day SIC is above 80%); day of retreat (last day SIC drops below 15%); day of advance (first day SIC increases above 15%); day of closing (first day SIC increases above 80%); total outer ice-free period; total inner ice-free period; seasonal loss-of-ice period; seasonal gain-of-ice period; and the seasonal ice zone.

These data are available for 1979 through 2017. They are gridded on the NSIDC northern hemisphere polar stereographic grid at 25 km.

This is the most recent version of these data.

Version Summary:

Initial Release

STANDARD Level of Service

Data: Data integrity and usability verified

Documentation: Key metadata and user guide available

User Support: Assistance with data access and usage; guidance on use of data in tools

See All Level of Service Details

Parameter(s):
  • SNOW/ICE > ICE GROWTH/MELT
  • SEA ICE > SEA ICE CONCENTRATION
Data Format(s):
  • NetCDF
Spatial Coverage:
N: 90, 
S: 30, 
E: 180, 
W: -180
Platform(s):DMSP 5D-2/F11, DMSP 5D-2/F13, DMSP 5D-2/F8, DMSP 5D-3/F17, DMSP 5D-3/F18, Nimbus-7
Spatial Resolution:
  • 25 km x 25 k m
Sensor(s):SMMR, SSM/I, SSMIS
Temporal Coverage:
  • 1 March 1979 to 28 February 2018
Version(s):V1
Temporal Resolution1 yearMetadata XML:View Metadata Record
Data Contributor(s):Steele, M., A. C. Bliss, G. Peng, W. N. Meier, and S. Dickinson.

Geographic Coverage

Download Via HTTPS: An Earthdata Login account is required to access these data.

Once you have logged in, you will be able to click and download files via a Web browser. There are also options for downloading via a command line or client. For more detailed instructions, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Steele, M., A. C. Bliss, G. Peng, W. N. Meier, and S. Dickinson. 2019. Arctic Sea Ice Seasonal Change and Melt/Freeze Climate Indicators from Satellite Data, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/KINANQKEZI4T. [Date Accessed].
Created: 
11 June 2019
Last modified: 
30 September 2020

Data Description

Parameters

The parameters for this data set are described in Table 1.

Table 1. Parameter Descriptions
Parameter name as it appears in the netCDF file Description Units
AHRA MO Earliest melt onset date derived from Advanced Horizontal Range Algorithm (AHRA) algorithm (Anderson et al. 2014) Day of year 
EMO Early melt onset date (Markus et al. 2009) Day of year 
EFO Early freeze onset date (Markus et al. 2009) Day of year 
CMO Continuous melt onset date (Markus et al. 2009) Day of year 
CFO Continuous freeze onset date (Markus et al. 2009) Day of year 
DOO Day of opening; last day the sea ice concentration drops below 80% Day of year 
DOR Day of retreat; last day sea ice concentration drops below 15% Day of year 
DOA First day of advance; first day sea ice concentration increases above 15% Day of year 
DOC First day of closing; first day sea ice concentration increases above 80% Day of year 
OIFP Outer ice-free period; DOC - DOO Days
IIFP Inner ice-free period or the open-water period; DOA - DOR Days
SLIP Seasonal loss of ice period; DOR - DOO Days
SGIP Seasonal gain of ice period; DOC-DOA Days
SIZ Seasonal ice zone Days

File Information

Format

The data are provided in a single netCDF (.nc) file.

An Extensible Markup Language (.xml) file with associated metadata is also provided.

Naming Convention

The file name is:
arctic_seaice_climate_indicators_nh_v01r01_1979-2017.nc

File Size

The data file is approximately 38 MB.

Spatial Information

Coverage

Northernmost Latitude: 90° N
Southernmost Latitude: 30° N
Easternmost Longitude: 180° W
Westernmost Longitude: 180° W

Resolution

25 km

Geolocation

The following tables provide a description of the projection and grid used for this data set.

Table 2. Geolocation Details
Geographic coordinate system Unspecified datum based upon the Hughes 1980 ellipsoid
Projected coordinate system NSIDC Sea Ice Polar Stereographic North
Longitude of true origin -45
Latitude of true origin 70
Scale factor at longitude of true origin 1
Datum Not_specified_based_on_Hughes_1980_ellipsoid
Ellipsoid/spheroid Hughes 1980
Units meter
False easting 0
False northing 0
EPSG code 3411
PROJ4 string +proj=stere +lat_0=90 +lat_ts=70 +lon_0=-45 +k=1 +x_0=0 +y_0=0 +a=6378273 +b=6356889.449 +units=m +no_defs 
Reference https://epsg.io/3411

Table 3. Grid Details
Grid cell size (x, y pixel dimensions) Grid cell size varies with location
Number of rows 448
Number of columns 304
Geolocated lower left point in grid 33.92° N, 279.26° W
Nominal gridded resolution 25 km x 25 km
Grid rotation N/A
ulxmap – x-axis map coordinate of the center of the upper-left pixel (XLLCORNER for ASCII data) -3850 projected km
ulymap – y-axis map coordinate of the center of the upper-left pixel (YLLCORNER for ASCII data) 5850 projected km

Temporal Information

Coverage

01 March 1979 through 28 February 2018

Resolution

Yearly

Annual sea ice paramters are tracked through February of the following year. For example, 2016 fields were derived from input sources spanning 1 March 2016 through 28 February 2017.

Data Acquisition and Processing

Background

This product contains a suite of sea ice melt-season indicators. Parameters track the evolution of the Sea Ice Concentration (SIC) from early to continuous surface melt onset, including when the ice cover opens (SIC drops below 80%); retreats, i.e. becomes open water (SIC drops below 15%); advances, i.e. ice starts to form (SIC rises above 15%); and closes (SIC increases above 80%). These sea ice descriptions provide an assessment of how the melt season is changing across the Arctic. The gridded format of these data allow these changes to be observed on a regional scale.

The melt-onset parameters are derived from Brightness Temperature (Tb) data collected on different Passive Microwave (PM) channels. Melt onset is detectable because PM Tb are sensitive to the state of water (frozen vs. liquid).

Acquisition

The data derive from Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave/Imager (SSM/I), and Special Sensor Microwave Imager/Sounder (SSMIS) Brightness Temperature (Tb) observations. Input data come from the NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 3 (Meier et al. 2017) and the DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures, Version 4 (Maslanik and Stroeve 2004) data sets at NSIDC.

Processing

A SIC mask is used to constrain where melt onset is calculated from Tb. This mask is derived from the Merged Goddard parameter in the NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration data set. For each grid cell and each melt-season parameter, a multi-day smoothing is applied to remove noise from synoptic events (e.g. short-term ice growth/melt or advection). Further details on processing steps, and the product in general, can be found in Biiss et al. (2019) and Peng et al. (2018).

Quality, Errors, and Limitations

First, though the data are gridded at a resolution of 25 km, the SMMR, SSM/I, and SSMIS sensors have much coarser spatial resolutions (up to ~45 km x ~70 km), so Tb observations may not capture smaller openings in the ice. Second, surface melt during the summer, and new ice formation during the fall and winter, can bias SIC estimates dervied. Surface melt tends to skew the Day of Opening (DOO) (and possibly the Day of Retreat, DOR) earlier in the year and the First Day of Advance (DOA) and the First Day of Closing (DOC) later.

Instrumentation

For a description of the SMMR, SMMI, SSMI/S instruments, visit the SMMR, SSM/I, and SSMIS Sensors Summary.

Related Data Sets

NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 3

DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures, Version 4

Version History

Table 4. Version History Summary
Version Summary
1.1

Changes and updates to this version include:

  • The data record was updated through 2017.
  • The full data record was also reprocessed to correct an error in the CFO field. In the previous version, the CFO field was written with a copy of the EFO field.
  • Some geophysical data fields (e.g. year) were updated in the netCDF file to better reflect common netCDF practices (e.g. the year field is now labeled as time).
1.0 Initial release

Contacts and Acknowledgments

Contacts

Michael Steele
Polar Science Center
Applied Physics Laboratory
University of Washington
Seattle, Washington 98105

Walter N. Meier
The National Snow and Ice Data Center
University of Colorado
Boulder, Colorado 80309

Angela Bliss
Earth System Science Interdisciplinary Center
University of Maryland / NASA Goddard
Baltimore, Maryland

Peng Ge
North Carolina Institute for Climate Studies, North Carrolina State University
NOAA Centers for Environmental Information (NCEI)
Raleigh, North Carolina

Acknowledgements

The data set was produced with funding from the NASA Climate Indicators program (NNH14ZDA001N-INCA).

References

Anderson, M., A. C. Bliss, and S. Drobot. 2019. Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I-SSMIS Brightness Temperatures, Version 4. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: 10.5067/A9YK15H5EBHK

Bliss, A.C., M. Steele, G. Peng, W.N. Meier, and S. Dickinson. 2019. "Regional variability of Arctic sea ice seasonal change climate indicators from a passive microwave climate data record." Env. Res. Lett., 14, Art. No. 045003. doi: 10.1088/1748-9326/aafb84

Markus, T., J. C. Stroeve, and J. Miller. 2009. "Recent changes in Arctic sea ice melt onset, freezeup, and melt season length." J. Geophys. Res. 114(C12):C12024. doi: 10.1029/2009JC005436

Maslanik, J. and J. Stroeve. 2004. DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures, Version 4. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: 10.5067/AN9AI8EO7PX0

Meier, W. N., F. Fetterer, M. Savoie, S. Mallory, R. Duerr, and J. Stroeve. 2017. NOAA/NSIDC Climate Data Record of Passive Microwave Sea Ice Concentration, Version 3. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: 10.7265/N59P2ZTG

Peng, G., M. Steele, A.C. Bliss, W.N. Meier, and S. Dickinson. 2018. "Temporal means and variability of Arctic sea ice melt and freeze season climate indicators using a satellite climate data record." Rem. Sens., 10, Art. No. 1328. doi: 10.3390/rs10091328

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