MODIS

Moderate Resolution Imaging Spectroradiometer
In this section
Version History

The following information summarizes the differences between various versions of MODIS data.

Current Version: V61 (Collection 6.1)

Temporal Coverage

2002-07-04 to present (Aqua) and 2000-02-24 to present (Terra)

Version Summary

The snow cover algorithm is revised in Version 6.1 (61) to include:

  • The low visible reflectance screen for snow cover using bands 2 and 4 was lowered to 0.07 reflectance from 0.10 in C6. The result of lowering the threshold was a reduction in the occurrence of “no decision” results in the algorithm.
  • Two algorithm bit flags; “probably cloudy” and “probably clear” are set in the algorithm flags QA dataset. These flags can be used to investigate cloud/snow confusion in some situations.

There were no significant changes to the sea ice or ice surface temperature algorithms.

Processing History

February 2020: Reprocessing begins for MODIS Aqua and Terra Version 61 (Collection 6.1) snow and sea ice data sets. Reprocessing consists of multiple parallel streams.

March 2021: Reprocessing completes a sufficient volume of MODIS Version 61 (Collection 6.1) to allow for public release. Forward processing beings and reprocessing continues along multiple parallel streams.

January 2022: Reprocessing completes for all MODIS V61 (Collection 6.1) data sets.

Version 6 (Collection 6)

Temporal Coverage

2002-07-04 to 2023-02-25 (Aqua) and 2000-02-24 to 2023-02-17 (Terra)

NOTE: Dates indicate temporal coverage, not dates of NSIDC holdings. Data from previous MODIS versions are only maintained for the so-called "Golden Month," a 40-day window from 29 August, 2002 to 7 October, 2002. Golden Month data are available by special request from NSIDC User Services. For more information about the Golden Month, see MODIS Golden Month Products on the LP DAAC MODIS Overview Web page.

Version Summary

The snow cover algorithms and data sets are significantly revised in Version 6. Changes include:

  • Aqua MODIS band 6 has been restored to scientific quality using a Quantitative Image Restoration (QIR) technique. The snow detection algorithms are now the same for Aqua and Terra;
  • Fractional Snow Cover has been replaced by Normalized Difference Snow Index (NDSI) snow cover. Fractional Snow Cover is no longer calculated;
  • The binary Snow-Covered Area (SCA) map has been discontinued;
  • Data screens designed to reduce snow detection errors have been revised and several new screens have been added;
  • Data screen results are provided in a new QA bit flag, including snow detection reversals and detections with increased uncertainty;
  • Basic pixel-level QA uses new criteria to indicate the overall quality of algorithm result;
  • Daily snow cover data sets include SDSs with pointers to the swaths used as the observation of the day.

The sea ice extent and ice surface temperature algorithms and data sets are the same as Version 5. However, revisions and improvements for Version 6 to sea ice algorithm inputs—in particular, the L1B calibrated radiances, land and water mask, and cloud mask—have improved sea ice outputs as follows:

  • Revised calibration of thermal bands 31 and 32 decreased calculated brightness temperatures by about -0.01 K and improved accuracy for very cold scenes (especially below ~ -30°C);
  • The Version 6 land/water mask (stored in the MOD03 geolocation product) increased the accuracy of water body and coastline maps;
  • Revisions to the cloud mask algorithm have increased the accuracy of cloud detection.

Processing History

April 2015: Forward processing begins for MODIS Aqua and Terra Version 6 (Collection 6) sea ice data sets. Reprocessing begins from the start of both missions and the data are released in real time as they are reprocessed.

January 2016: Forward processing begins for MODIS Aqua and Terra Version 6 (Collection 6) snow cover data sets. Reprocessing consists of five parallel streams, starting on Day 1 of the years 2000, 2003, 2006, 2009, and 2012.

November 2015: Version 6 reprocessing completes for all MODIS sea ice data sets.

July 2016: Version 6 reprocessing completes for all MODIS snow cover data sets.

February 2023: Forward processing ceases for all MODIS V6 data sets.

Version 5 (Collection 5)

Temporal Coverage

2002-07-04 to 2017-01-02  (Aqua) and 2000-02-24 to 2017-01-02 (Terra)

NOTE: Dates indicate temporal coverage, not dates of NSIDC holdings. Data from previous MODIS versions are only maintained for the so-called "Golden Month," a 40-day window from 29 August, 2002 to 7 October, 2002. Golden Month data are available by special request from NSIDC User Services. For more information about the Golden Month, see MODIS Golden Month Products on the LP DAAC MODIS Overview Web page.

Version Summary

  • A conservative cloud mask is used exclusively.
  • Monthly snow products are available in a Climate Modeling Grid (CMG).
  • Fractional snow cover was added to MYD10_L2 and MYD10A1.
  • Sea Ice by Ice Surface Temperature (IST) and combined sea ice fields were removed from all sea ice products.
  • Browse images are available for all products.
  • V005 products use HDF compression making the file size much smaller.

Processing History

08 September 2006: Version 5 (V005) MODIS Terra reprocessing begins. The reprocessing campaign is proceeding in time order from the beginning of the mission (24 February 2000).

08 December 2006: V005 MODIS Terra sea ice products were released.

15 December 2006: V005 MODIS Terra snow and sea ice products were released. Because of processing problems, only products dating from after September 1, 2000 are available. Products between February 24, 2000 to September 1, 2000 will be available in mid-2007.

12 January 2007: V005 MODIS Aqua snow and sea ice products were released. Production of V005 forward stream data started 1 January 2007. Reprocessing of existing V005 data is expected to begin in mid-2007 and to take about one year.

27 January 2007: There was a processing error that affected all MODIS Terra Version V005 products at 500 m resolution. This error resulted in stripes of missing data produced between January 27, 2007 and March 21, 2007. Since that time, a fix was implemented and all affected data were reprocessed.

May 2008: The full reprocessing of MODIS V005 data was completed in May of 2008.

January 2017: Forward processing ceased for all MODIS V005 data.

Version 4 (Collection 4)

Temporal Coverage

2002-07-04 to 2007-01-03  (Aqua) and 2000-02-24 to 2007-01-03 (Terra)

NOTE: Dates indicate temporal coverage, not dates of NSIDC holdings. Data from previous MODIS versions are only maintained for the so-called "Golden Month," a 40-day window from 29 August, 2002 to 7 October, 2002. Golden Month data are available by special request from NSIDC User Services. For more information about the Golden Month, see MODIS Golden Month Products on the LP DAAC MODIS Overview Web page.

Version Summary

  • A conservative cloud mask is used exclusively.
  • Monthly snow products are available in a Climate Modeling Grid (CMG).
  • Fractional snow cover was added to MYD10_L2 and MYD10A1.
  • Sea Ice by Ice Surface Temperature (IST) and combined sea ice fields were removed from all sea ice products.
  • Browse images are available for all products.
  • V005 products use HDF compression making the file size much smaller.

Processing History

20 December 2002: Reprocessing of Terra V003 granules to Terra V004 algorithm begins for all products dated 24 February 2000 (day 055) onward. Terra V003 granules will be available at least six months after they have been reprocessed to the Terra V004 algorithm.

01 January 2003: Forward processing for the Terra V004 algorithm begins for all products.

10 January 2003: Terra V004 products are available to the public.

January 2004: All Aqua V003 granules from 04 July 2002 onward are being reprocessed to Aqua V004. Forward processing of Aqua V004 begins.