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Data Set ID:
NSIDC-0116

Polar Pathfinder Daily 25 km EASE-Grid Sea Ice Motion Vectors, Version 4

This data set contains daily and weekly sea ice motion vectors, as well as browse images representing the weekly data. Input data sources, derived from AVHRR, AMSRE, SMMR, SSMI, and SSMI/S sensors; IABP buoys; and NCEP/NCAR Reanalysis forecasts, used to generate the daily and weekly sea ice motion estimates are also included.

This is the most recent version of these data.

Version Summary:

Changes to this version include:
Data are provided in georeferenced netCDF format rather than ASCII and raw binary files
Merge 15 highest-weighted rather than 15 closest input vectors
Improved filtering of SSMI inputs
Each buoy provides one daily motion estimate instead of separate noon and midnight estimates
Monthly ice motion estimates are no longer provided

COMPREHENSIVE Level of Service

Data: Data integrity and usability verified; data customization services available for select data

Documentation: Key metadata and comprehensive user guide available

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

See All Level of Service Details

Parameter(s):
  • SNOW/ICE > ICE VELOCITY
  • SEA ICE > SEA ICE MOTION
Data Format(s):
  • PNG
  • NetCDF
Spatial Coverage:
N: -53.2028, 
N: 90, 
S: -90, 
S: 48.4, 
E: 180, 
E: 180, 
W: -180
W: -180
Platform(s):AQUA, BUOYS, DMSP 5D-2/F11, DMSP 5D-2/F13, DMSP 5D-2/F8, DMSP 5D-3/F17, NOAA-11, NOAA-12, NOAA-14, NOAA-9, Nimbus-7
Spatial Resolution:
  • Varies x Varies
  • 25 km x 25 km
Sensor(s):AMSR-E, AVHRR, DRIFTING BUOYS, SMMR, SSM/I, SSMIS
Temporal Coverage:
  • 25 October 1978 to 31 December 2018
Version(s):V4
Temporal Resolution1 day, 7 dayMetadata XML:View Metadata Record
Data Contributor(s):Walter Meier, J Stewart, Charles Fowler, Jim Maslanik

Geographic Coverage

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.

Tschudi, M., W. N. Meier, J. S. Stewart, C. Fowler, and J. Maslanik. 2019. Polar Pathfinder Daily 25 km EASE-Grid Sea Ice Motion Vectors, Version 4. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/INAWUWO7QH7B. [Date Accessed].
Created: 
25 February 2019
Last modified: 
21 March 2019

Data Description

Parameters

The main parameters for this data set are daily and weekly sea ice motion (cm/s). Sea ice motion is divided into along-x (u) and along-y (v) components. Error variance (for daily data) and the number of contributing files (for weekly data) are also provided.

Additionally, the input data used to calculate daily and weekly sea ice motion vectors are included in this data set. The input data consist of sea ice motion vectors derived from specific sensors (see Table 2 for more details).

File Information

Format

Daily and weekly sea ice motion are provided in georeferenced netCDF (.nc) format. Input data are also provided in netCDF (.nc) format.

PNG (.png) browse images and Extensible Markup Language (.xml) files with associated metadata are also included.

Daily and Weekly Sea Ice Motion File Contents

Daily and weekly sea ice motion netCDF file contents are described in Table 1 and represented in Figure 1.

Table 1. Summary of Daily and Weekly Sea Ice Motion File Contents
Variable Description Units
u Along-x component of the sea ice motion (not the eastward velocity); scaled by a factor of 10 cm/s
v Along-y component of the sea ice motion (not the northward velocity); scaled by a factor of 10 cm/s
icemotion_error_estimate Ice motion error variance; only included in the daily data files N/A
number_of_observations Number of contributing daily files; only included in the weekly data files Number of daily files
latitude Latitude  ° N
longitude Longitude ° E
crs Coordinate reference system (e.g. EASE-Grid North 25 km) N/A
x X coordinate Projected meters
y Y coordinate Projected meters
time Time of measurement Calendar day (daily data files)
Date range (weekly data files)
Figure 1. Sample of daily along-x component of sea ice motion from 01 January 1982. Figure produced in the netCDF-visualization software Panoply.

Browse Image File Contents

One browse image displaying weekly sea ice motion is provided for every week of data. Figure 2 contains a sample browse image.

Figure 2. Sample browse image displaying sea ice motion for the week of 01 January to 07 January 2017.

Input Data File Contents

Input data files are described in Table 2. All input data files contain the same variables and structure, except for the IABP buoy data. Since the buoy data are point-source data, they are stored as a list, not as a georeferenced grid. Input data fields are described in more detail in Tables 3 and 4.

Table 2. Summary of Input Sea Ice Motion Data Sets
Source Spatial Resolution
AVHRR 50km
AMSR-E 37.5 km
SMMR 75 km
SSM/I 75 km
SSMIS 75 km
National Center for Environmental Prediction (NCEP) / National Center for Atmospheric Research (NCAR) Reanalysis U-wind and V-wind data 50 km
International Arctic Buoy Program (IABP) buoys Point source, locations indexed to 25 km EASE-Grid
Table 3. Summary of Input Data File Contents
Variable
Description
Units
U Along-x component of the sea ice motion (not the eastward velocity); scaled by a factor of 10 cm/s
V Along-y component of the sea ice motion (not the northward velocity); scaled by a factor of 10 cm/s
AMSRE_quality_info1 Correlation coefficient; ranges from 0.0 - 1.0 N/A
S*_source2 Indicates the input source channel (S* = SMMR, SSMI, or SSMIS)
SMMR sensor:
1 = The vector was from the 37V GHz channel
2 =  The vector was from both 37 GHz channels
SSM/I and SSMIS sensors:
1 = The vector was from the 37V GHz channel
2 = The vector was from both 37 GHz channels
3 = The vector was derived from the 85V GHz channel
N/A
number_of_AVHRR_observations3 The number of vectors averaged together at a given location, includes up to four passes and two channels (infrared and visible) N/A
Wind_Source4 Indicates that the input source for this data set was the NCEP/NCAR U-wind and V-wind data set N/A
Latitude
Latitude 
° N
Longitude
Longitude
° E
CRS Coordinate reference system (e.g. EASE-Grid North 25 km) N/A
X
Projected x coordinate
Projected meters
Y
Projected y coordinate
Projected meters
Time Time of measurement Julian day
1only appears in the AMSRE input data files
2only appears in the SMMR, SSMI, and SSMI/S input data files
3only appears in the AVHRR input data files
4only appears in the NCEP/NCAR input data files
Table 4. Summary of IABP Buoy File Contents
Variable Description Units
U Along-x component of the sea ice motion (not the eastward velocity); scaled by a factor of 10 cm/s
V Along-y component of the sea ice motion (not the northward velocity); scaled by a factor of 10 cm/s
observation_date Day of observation Days since 1970-01-01
buoy_ID IABP buoy number N/A
X Projected x coordinate on the 25 km EASE-Grid Projected meters
Y Projected y coordinate on the 25 km EASE-Grid Projected meters

Directory Structure

Data are available for download via HTTPS; the link is accessible through the "Download Data" tab. 

Within the file directory, there are two main subdirectories: browse and data. Within these subdirectories, folders are subdivided by hemisphere and data type. Table 5 provides a listing of the subfolders.

Table 5. Data and Browse Directory Structure
Data Subdirectory
Description
/north/amsre/
Contains the AMSR-E-derived input data files. These files are only available for the Northern Hemispehre.
/north/avhrr/
/south/avhrr/
Contains the AVHRR-derived input data files.
/north/buoy/
Contains the IABP buoy-derived input data files. These files are only available for the Northern Hemispehre.
/north/smmr/
/south/smmr
Contains the SMMR-derived input data files. 
/north/ssmi/
/south/ssmi/
Contains the SSM/I-derived input data files.
/north/ssmis/
/south/ssmis/
Contains the SSMIS-derived input data files.
/north/week/
/south/week/
Contains the weekly sea ice motion data files.
/north/ssmis/
/south/ssmis/
Contains the SSMIS-derived input data files.
/north/wind/
Contains the NCEP/NCAR-derived input data files.
Browse Subdirectory
Description
/north/week/
/south/week/
Contains the browse images of all of the weekly mean fields. Within this directory, the data are divided by year.

Daily and Weekly Sea Ice Motion File Naming Convention

The daily and weekly data files are named according to the following convention and as described in Table 6:
icemotion_<daily|weekly>_hh_rrrr_yyyy.nc

Example:
icemotion_daily_nh_25km_2000.nc
icemotion_weekly_nh_25km_2000.nc

Table 6. Daily and Weekly Sea Ice Motion File Naming Convention
Variable Description
<daily|weekly> Indicates whether the file contains daily or weekly sea ice motion values
hh Hemisphere (nh = Northern, sh = Southern)
rrrr Resolution of input data in km (e.g. 50 km)
yyyy 4-digit year

Browse Image File Naming Convention

The browse images are named according to the following convention and as described in Table 7:
icemotion_weekly_hh_rrrr_<start-date>_<end-date>.png

Example:
icemotion_weekly_nh_25km_20000101_20000108.png

Table 7. Browse Image File Naming Convention
Variable Description
hh Hemisphere (nh = Northern, sh = Southern)
rrrr Resolution of input data in km (e.g. 50 km)3
<start-date> First day of the week that the image represents, written in yyyymmdd (4-digit year, 2-digit month, 2-digit day) format
<end-date> Last day of the week that the image represents, written in yyyymmdd (4-digit year, 2-digit month, 2-digit day) format

Input Data File Naming Convention

The input data files are named according to the following convention and as described in Table 8:
im_from_<source>_hh_rrrr_yyyy.nc

Example:
im_from_amsre_nh_37.5km_1982.nc

Table 8. Input Data File Naming Convention
Variable Description
im_from Indicates that the file contains sea ice motion estimates used as input for the daily sea ice motion calculations
<source> Input data source (amsre, smmr, ssmi, ssmis, buoy1, or wind2)
hh Hemisphere (nh = Northern, sh = Southern)
rrrr Resolution of input data, in km (e.g. 50 km)3
yyyy 4-digit year
1Available for Northern Hemisphere only
2Indicates that the data come from the NCEP/NCAR Reanalysis U-wind and V-wind at 10 m data set
3The resolution is described as "list" for point-source data

File Size

Daily sea ice motion files range from approximately 18.0 - 22.0 MB.
Weekly sea ice motion files range from approximately 3.0 - 4.0 MB.
Input data files range from approximately 0.2 - 8.0 MB.

Browse images are approximately 0.5 - 1.5 MB.

Spatial Information

Coverage

Daily and weekly sea ice motion data are confined to the poles in the Northern and Southern Hemisphere, as represented in Figure 3.

Figure 3. Spatial coverage map for the Northern Hemisphere (left) and Southern Hemisphere (right).

Resolution

The final daily and weekly sea ice motion data are provided at a resolution of 25 km. Input data have different spatial resolutions (see Table 2). 

Geolocation

Daily and weekly sea ice motion data are georeferenced to the Northern and Southern 25 km EASE-Grid projections. More details on these projections and grids are provided in the tables below. More details on EASE-Grid can be found on the EASE Grids website.

Table 9. Geolocation Details for the Northern EASE-Grid
Geographic coordinate system N/A
Projected coordinate system NSIDC EASE-Grid North
Longitude of true origin 0
Latitude of true origin 90
Scale factor at longitude of true origin N/A
Datum N/A
Ellipsoid/spheroid International 1924 Authalic Sphere
Units meter
False easting 0
False northing 0
EPSG code 3408
PROJ4 string
+proj=laea +lat_0=90 +lon_0=0 +x_0=0 +y_0=0 +a=6371228 +b=6371228 +units=m +no_defs 
Reference http://epsg.io/3408

Table 10. Grid Details for the Northern EASE-Grid
Grid cell size (x, y pixel dimensions) 25067.5 projected meters (x)
25067.5 projected meters (y)
Number of rows 361
Number of columns 361
Geolocated lower left point in grid 36.95776° S, 135.00000° W
Nominal gridded resolution 25 km by 25 km
Grid rotation N/A
ulxmap – x-axis map coordinate of the outer edge of the upper-left pixel -4524688
ulymap – y-axis map coordinate of the outer edge of the upper-left pixel +4524688
Table 11. Geolocation Details for the Southern EASE-Grid
Geographic coordinate system N/A
Projected coordinate system NSIDC EASE-Grid South
Longitude of true origin 0
Latitude of true origin 90
Scale factor at longitude of true origin N/A
Datum N/A
Ellipsoid/spheroid International 1924 Authalic Sphere
Units Meter
False easting 0
False northing 0
EPSG code 3409
PROJ4 string
+proj=laea +lat_0=-90 +lon_0=0 +x_0=0 +y_0=0 +a=6371228 +b=6371228 +units=m +no_defs 
Reference http://epsg.io/3409

Table 12. Grid Details for the Southern EASE-Grid
Grid cell size (x, y pixel dimensions) 25067.5 projected meters (x)
25067.5 projected meters (y)
Number of rows 321
Number of columns 321
Geolocated lower left point in grid 36.95776° S, 135.00000° W
Nominal gridded resolution 25 km by 25 km
Grid rotation N/A
ulxmap – x-axis map coordinate of the outer edge of the upper-left pixel  -40233378
ulymap – y-axis map coordinate of the outer edge of the upper-left pixel  +40233378

Temporal Information

Coverage and Resolution

The temporal coverage and resolution vary by data type and sensor. See Table 13 for more details.

Table 13. Temporal Coverage and Resolution for Daily and Weekly Sea Ice Motion and Input Data
Data
Source
Start Date
End Date
Resolution
Daily Sea
Ice Motions
Interpolated from input data
31 October 1978
31
December 2018
Daily
Weekly Sea
Ice Motions
Averaged from Daily Sea Ice Motions
05 November 1978
31 December 2018
Weekly
Input Data
AMSR-E
19 June 2002
08 August 2011
Data are available every day for any given grid cell.
AVHRR
24 July 1981

 31 December 2000

Four satellite passes are used each day when available.
IABP buoys
18 January 1979
31
December 2018
The 12:00 Greenwich Mean Time (GMT) buoy positions
were used to compute 24-hour mean velocities.
NCEP-NCAR
01 November 1978
31
December 2018
Data are available every day for any given grid cell.
SMMR
25 October 1978
08 July 1987
Data are available every other day for any given grid cell. See the SMMR 48 Hour Temporal Resolution Consequences for more information.
SSM/I
09 July 1987
31 December 2006
Data are available every day for any given grid cell.
SSMIS
01 January 2007
31
December 2018
Data are available every day for any given grid cell.

Data Acquisition and Processing

Background

Sea ice movement is measured using imagery acquired by frequent, repeat coverage by remote sensing instruments. Ice motion computed from satellite imagery represents the displacement between two images with the same spatial coverage taken at different acquisition times. Researchers identify a feature, such as an ice floe, on two registered images and measure its pixel displacement. Ice velocity vectors are computed based on the pixel resolution and the time span between images.

A more automated method is to measure the correlation of groups of pixels between image pairs. A small target area in one image is correlated with several areas of the same size in a search region of the second image. The displacement of the ice is then defined by the location in the second image where the correlation coefficient is the highest. This is the spatial correlation method used to produce sea ice motion vectors for this data set.

The approach used for this data set is generally valid over short distances away from the ice edge in areas where ice conditions are relatively stable from day to day. Spatial correlation methods cannot find matches between images where a complete knowledge of ice dynamics is needed, e.g. in areas where ice is deforming or in the ice margins near the open ocean where the spatial or spectral characteristics of the ice within a pixel are changing rapidly (Emery, Fowler, and Maslanik 1995).

Acquisition

AVHRR Input Data

This input data derived sea ice motion vectors from AVHRR channel 2 (visible band) and channel 4 (infrared) Global Area Coverage (GAC) images. These images have a 50 km gridded resolution, are available for nearly two decades, provide an intermediate spatial resolution between passive microwave and buoys, and have a finer time sampling than microwave data.

Beginning with Version 3 of this data set, misregistered AVHRR estimates were removed.

For more information on AVHRR input data, please refer to: AVHRR Polar Pathfinder Twice-Daily 5 km EASE-Grid Composites.

Buoy Input Data

This input data derived sea ice motion vectors from International Arctic Buoy Program (IABP) C buoy position data. IABP provides buoy location information through satellite tracking of buoys placed on sea ice. Several buoy locations are determined each day and corresponding sea ice motions are calculated. Sea ice motion estimates from buoys are very accurate, but they are limited since the numbers and locations of buoys are driven by cost and logistics. In addition, buoys have not been placed on ice in the Eastern Arctic.

IABP buoy locations are generally provided every 12 hours: at noon and at midnight Greenwich Mean Time (GMT). This sea ice motion product uses 24-hour motion estimates from the IABP. For example, the IABP motion estimate for a buoy at noon on 01 January 2010 is derived by taking the difference of the buoy's location at noon on 02 January 2010 and its location at noon on 01 January 2010 and then dividing by 24 hours. The intervening midnight location value is not factored into the noon-to-noon 24-hour motion estimate. Similarly, the IABP motion estimate for midnight is calculated the same way, ignoring the intervening noon location information. Therefore, each buoy generally has two independent, 24-hour motion estimates: one for midnight and one for noon.  Beginning with Version 4 of this data set, the noon-time and midnight buoy vectors were averaged together to provide one buoy-derived sea ice motion per day. 

For more information the buoy input data, please refer to: International Arctic Buoy Program Air Droppable RAMS (ADRAMS) Buoy.

NCEP/NCAR Input Data

This input data derived sea ice motion vectors from the NCEP/NCAR Reanalysis wind data set. The data, called U-wind and V-wind at 10 m, are available from the NOAA Earth System Research Laboratory (ESRL) Physical Sciences Division (PSD).

For more information on the NCEP/NCAR input data, please refer to: NCEP/NCAR Reanalysis Data.

Passive Microwave Input Data

The passive microwave input data come from four different instruments: SMMR, SSM/I, SSMIS, and AMSR-E. All the source data are available for download from the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). The SMMR input data are derived from the NIMBUS-7 SMMR Pathfinder Brightness Temperatures data set. Due to satellite limitations, full Arctic coverage is only available every two days with SMMR; see the SMMR 48 Hour Temporal Resolution Consequences discussion for more information. The SSM/I and SSMIS input data both come from DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures, while the AMSR-E input data come from the AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures.

Table 14 lists the channels used by each passive microwave sensor to derive input sea ice motion vectors. In general, the passive microwave sensors provide all-sky coverage, whereas the AVHRR visible and infrared channels are limited by cloud cover. For more information on the passive microwave instruments, please refer to: 

Table 14. Channel Frequencies and Resolutions of the Passive Microwave Instruments
Instrument
Channel Frequency
Resolution
AMSR-E
89 GHz vertical
12.5 km
SMMR
37 GHz vertical and horizontal
25 km
SSM/I
37 GHz vertical and horizontal
85 GHz vertical and horizontal
25 km
12.5 km
SSMIS
37 GHz vertical and horizontal
91 GHz vertical and horizontal
25 km
12.5 km

Processing

The following steps were used to create this sea ice motion product.

  1. Compute the Sea Ice Motion Fields
    Detailed information about the methods used to compute sea ice motion for each input data source can be found here:
  2. Grid the Input Data to the 25 km EASE-Grid
    Each of the input sea ice motion estimates are mapped to the output grid (e.g. Northern Hemisphere 25 km EASE-Grid).

  3. Merge the Sea Ice Motion Fields
    Input sea ice motion estimates are combined to produce the daily sea ice motion product. Daily sea ice motion is a source- and distance-weighted average of the 15 highest-weighted input sea ice motion vectors. Each input data set is weighted according to the expected accuracy of the source data. For example, estimates derived from nearby buoys are weighted higher than NCEP/NCAR-derived estimates. Note that where data are sparse, the input data will be widely separated; when data are dense, only the very nearest estimates are considered. If the input sea ice motion estimates vary significantly from each other, this method can result in daily sea ice motion vectors that do not vary smoothly from one grid cell to the next.

  4. Calculate Daily Error Values
    The input vectors from the individual input sources (NCEP/NCAR, SSM/I, SSMIS, SMMR, AMSR-E, and AVHRR) are weighted separately based upon cross-correlations with buoy vectors. The optimal interpolation uses these weights, along with their distances from the location being estimated, to obtain the final error variance. If the closest input vector was greater than 1250 km, then a value of 1000 is added to this variable. Because interpolation was applied to a surface map from passive microwave data, coastlines may contain false ice. In this case, the third variable was assigned a negative value to allow users to remove these vectors near coastlines (within 25 km). For example, a value of -1035 indicates all of the following conditions: the vector was near a coastline, the nearest sampled vector was further than 1250 km, and the vector had a standard deviation (σ) of 3.5 and an estimated error variance (σ2) of 12.25.

  5. Compute Weekly Fields
    Weekly sea ice motion was computed from the daily gridded sea ice motion data for both the northern and southern polar regions. Weekly sea ice motion is an average of all the daily sea ice motions calculated for that week. At least four out of seven days were needed to compute the weekly mean.
    Weekly means for each year begin on 01 January for consistency. The last day of each year (or last two days if in a leap year) were excluded. In other words, the first week is always 01 January through 07 January and the last week of a year is either 24 December through 30 December or 23 December through 29 December (if in a leap year).

  6. Encode Data and Associated Metadata in netCDF Files
    Beginning with Version 4, data are provided in netCDF format.

Quality, Errors, and Limitations

Quality Assessment - Input Data

The following web pages provide information on the accuracy of sea ice motion estimates calculated from each input sensor:

Beginning with Version 3 of this data set, IABP buoy sea ice motion estimates above 70 cm/s were deemed physically unrealistic; thus, velocities that exceed this threshold were excluded from this data set. In addition, beginning with Version 4 of this data set, buoys which were outside the mask of valid sea ice motion (away from the coast, where sea ice concentration was greater than 15%) were excluded.

Quality Assessment - Daily and Weekly Sea Ice Motion Product

The icemotion_error_variance (daily data) and number_of_observations (weekly data) fields both provide a means of characterizing data quality. For the daily files, the error variance can indicate a "near coastline" check. For the weekly data, the more days that contributed to calculating the sea ice motion vector in a given grid cell, the higher the data quality. 

Missing Data

Beginning with Version 3 of this data set, there are some missing data in the Southern Hemisphere because there was not enough data from SSMI and AVHRR sensors to yield sea ice motion vectors. Missing data fields are left blank.

    Limitations

    The passive-microwave-derived sea ice motion estimates are based on changes in brightness temperature over consecutive days. The methods used to generate these input vectors requires fairly large areas of open ocean. As a result, ice motion cannot be calculated in regions of mixed land and ocean coverage, such as the Canadian Archipelago. The absence of sea ice motion estimates in such locations does not imply the absence of ice in these locations.

    Version History

      Table 15. Summary of Version Changes
      Version
      Date
      Description of Changes
      V4
      March 2019
      • Data are provided in georeferenced netCDF format rather than ASCII and raw binary files
      • Merge 15 highest-weighted rather than 15 closest input vectors
      • Improved filtering of SSMI inputs
      • Each buoy provides one daily motion estimate instead of separate noon and midnight estimates
      • Monthly and yearly sea ice motion estimates are no longer produced
      V3
      February 2016
      • Eliminated unrealistic AVHRR and IABP buoy velocities
      • Extended buoy sea ice motion estimates to the present
      • Improved browse images
      • Reprocessed SSMI fields using GDAL map transformations on the DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures Data Set, NSIDC-0001.
      • Used ice concentration estimates greater than 15 percent from the Sea Ice Concentrations from Nim bus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave data set, NSIDC-0051, to indicate where ice extent is present.
      V2
      Sep 2013
      • Added AMSR-E and NCEP/NCAR data for the Northern Hemisphere
      V1
      May 2003
      Original version of data. 
      Note: V1 is not indicated in Version 1 file names

      Related Data Sets

      AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures

      AVHRR Polar Pathfinder Twice-Daily 5 km EASE-Grid Composites

      AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites

      DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures

      NIMBUS-7 SMMR Pathfinder Brightness Temperatures

      Related Websites

      SMMR and SSM/I-SSMIS | Overview

      Contacts and Acknowledgments

      Mark Tschudi
      University of Colorado
      Colorado Center for Astrodynamics Research (CCAR)
      Department of Aerospace Engineering Sciences
      University of Colorado, Boulder
      431 UCB
      Boulder, Colorado USA 80309-0431

      Walter N. Meier
      University of Colorado Boulder
      449 UCB
      Boulder, CO 80309-0449

      J. Scott Stewart
      University of Colorado Boulder
      Boulder, CO 80309-0449

      Chuck Fowler 
      University of Colorado Boulder
      Boulder, CO 80309

      Jim Maslanik
      University of Colorado Boulder
      Boulder, CO 80309

      References

      Cavalieri, D. J., C. L. Parkinson, P. Gloersen, J. C. Comiso, and H. J. Zwally. 1999. Deriving long-term time series of sea ice cover from satellite passive-microwave multisensor data sets, J. Geophys. Res., 104(C7), 15803-15814. doi:10.1029/1999JC900081.

      Cavalieri, D., C. Parkinson, P. Gloersen, and H. J. Zwally. 1996, updated yearly. Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 1. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center. doi:10.5067/8GQ8LZQVL0VL.

      Cracknell, A. 1997. The Advanced Very High Resolution Radiometer. London: Taylor and Francis.

      Emery, W., C. Fowler, and J. Maslanik. 1995. Satellite Remote Sensing of Ice Motion, in Oceanographic Applications of Remote Sensing, ed. Motoyoshi Ikeda and Frederic W. Dobson. CRC Press, Boca Raton.

      Haumann, F. Alexander, Nicolas Gruber, Matthias Münnich, Ivy Frenger and Stefan Kern. 2016. Sea-ice transport driving Southern Ocean salinity and its recent trends. Nature 537:89-92. doi:10.1038/nature19101.

      Isaaks, E., and R. M. Srivastava. 1989. An Introduction to Applied Geostatistics. New York: Oxford University Press.

      Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G. White, J. Woollen, Y. Zhu, A. Leetmaa, R. Reynolds, M. Chelliah, W. Ebisuzaki, W. Higgins, J. Janowiak, K. Mo, C. Ropelewski, J. Wang, R. Jenne, and D. Joseph. 1996. The NCEP/NCAR 40-Year Reanalysis Project. Bulletin of the American Meteorological Society, 77, 437–471.

      Kidwell, K. 1995. NOAA Polar Orbiter Data User's Guide. U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, NESDIS.

      Kristler, R., et al. 2001. The NCEP–NCAR 50–Year Reanalysis: Monthly Means CD-ROM and Documentation. Bull. Amer. Meteor. Soc., 82, 247-267. doi: 10.1175/15200477(2001)082<0247:TNNYRM>2.3.CO;2.

      Krasnopolsky, V. M., L. C. Breaker, and W. H. Gemmill. 1995. A Neural Network as a Nonlinear Transfer Function Model for Retrieving Surface Wind Speeds from the Special Sensor Microwave Imager. Journal of Geophysical Research, 100(C6), 11,033–11,045.

      Maslanik, J., C. Fowler, J. Key, T. Scambos, T. Hutchinson, and W. Emery. 1998. AVHRR-based Polar Pathfinder Products for Modeling Applications. Annals of Glaciology 25:388-392

      Rosborough, G., D. Baldwin, and W. Emery. 1994. Precise AVHRR Image Navigation. IEEE Transactions in Geosciences and Remote Sensing 32(3):644-657.

      Schweiger, A., C. Fowler, J. Key, J. Maslanik, J. Francis, R. Armstrong, M. J. Brodzik, T. Scambos, T. Haran, M. Ortmeyer, S. Khalsa, D. Rothrock, and R. Weaver. 1999. P-Cube: A Multisensor Data Set for Polar Climate Research. Proceedings on the 5th Conference on Polar Meteorology and Oceanography, American Meteorological Society, Dallas, TX, 15-20 Jan., 136-141.

      Thorndike, A. S., and R. Colony. 1982. Sea Ice Motion in Response to Geostrophic Winds. J. Geophys. Res. 87(C8):5845–5852. doi:10.1029/JC087iC08p05845.

      Tschudi, M. A., Meier, W. N., and Stewart, J. S. 2019. An enhancement of sea ice motion and age products. The Cryosphere Discussion, in review. doi: 10.5194/tc-2019-40.

      No technical references available for this data set.

      How To

      How to import Polar Pathfinder Daily 25 km EASE-Grid Sea Ice Motion Vectors into ArcGIS
      This article describes the actions to perform in order work with NSIDC-0116 in ArcGIS. At the time of writing, this tutorial is relevant for ArcMap10.5 and earlier. The following steps will show you how to prepare the binary files for import, format conversion, geolocation/projection, and display... read more
      How to convert the horizontal and vertical components to east and north
      This article describes how to convert the u (horizontal) and v (vertical) components from the ice motion data set to East and North components on the Earth's surface. Instructions for both the Northern and Southern Hemispheres are described below: Northern Hemisphere In the Northern Hemisphere,... read more