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AMSR-E/Aqua Data at NSIDC
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Recently the AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures (AE_L2A) Version 2 product was determined to have errors in the resampled 89.0 GHz Horizontal (H) fields.
Files with data coverage from 19 June 2002 00:29 through 4 November 2004 05:43 are affected. The fields containing bad data are:
Only AE_L2A files with an algorithm product maturity indicator of V08 in the filename are affected. The previous B01 and B02 versions for that time period were processed correctly.
The problem was caused when vertically polarized 89.0 GHz brightness temperatures from the AMSR-E A Feedhorn were used instead of horizontally polarized brightness temperatures when computing the resampled 89 GHz H fields. When the A Feedhorn failed on 4 November 2004, this coding error was no longer a problem since from that point on, all 89.0 GHz brightness temperatures came from the B Feedhorn.
AE_L2A data between 19 June 2002 00:29 through 4 November 2004 05:43 will be reprocessed to correct the problem using algorithm version V09. AE_L2A V08 data from 4 November 2004 05:43 to the present can be used without concern in conjunction with V09. Eventually all V08 data will be reprocessed to V09 for consistency.
On 2 December 2007, an anomaly developed on the Aqua spacecraft which prevented the production of Ground Based Attitude Determination (GBAD) data. Due to the loss of GBAD data, AMSR-E data production was stopped. Data production resumed on 7 December 2007; however, products are slightly delayed. Production is expected to return to normal by 12 December. All data for 2 December through 6 December is expected to be recovered and will be available from NSIDC.
On 9 May 2007, production of Version 2 of the AMSR-E/Aqua L2B Global Swath Ocean Products derived from Wentz Algorithm (AE_Ocean) began. The AE_Ocean algorithm incremented from B05 (beta) to V05 (validated). A validated algorithm has been verified by the algorithm team and validated by the validation teams. The V05 AE_Ocean algorithm includes improved beamfilling correction and more accurate rain flags.
On 19 April 2007, production of Version 2 of the AMSR-E/Aqua L2B Surface Soil Moisture, Ancillary Parms, & QC EASE-Grids (AE_Land) product began. The AE_Land algorithm incremented to T06 (transitional), replacing the previous B05 (beta) algorithm. Product maturity progresses from beta to transitional as the algorithm matures and stabilizes.
Reprocessing of the AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures (AE_L2A) data is complete. The reprocessing campaign goes back to the start of the AMSR-E mission. Data from 18 June 2002 to the present are now at Version 2 (V09), the validated version of the AE_L2A algorithm.
A new version of the AMSR-E/Aqua L2B Global Swath Rain Rate/Type GSFC Profiling Algorithm (AE_Rain) is available at NSIDC. Beginning 13 November 2006, AE_Rain data are considered validated and have incremented from Version 1 to Version 2. The product maturity indicator, found in the AE_Rain filename, has changed from B08 (B = beta) to V09 (V = validated). This new version does not include any changes to the science algorithm.
Reprocessing has begun for the AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures (Tb) (AE_L2A) data back to the start of the AMSR-E mission. Data will be reprocessed to Version 2 (V002) beginning with data from 18 June 2002 forward to 1 August 2006 when the Version 2 algorithm was implemented. Data will be available via the Data Pool and the EOS Data Gateway (EDG) as the data are reprocessed.
A new version of the AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures (Tb) (AE_L2A) is now available. Beginning on 01 August 2006, AE_L2A data are considered validated and have incremented from Version 1 to Version 2. The product maturity indicator, found in the AE_L2A filename, has changed from B07 (B = beta) to V08 (V = validated). This new version does not include any changes to the science algorithm.
Reprocessing of the AMSR-E/Aqua L1A Raw Observation Counts (AMSREL1A) data with the Version 2 algorithm is completed. Version 2 AMSREL1A data is now available from 18 June 2002 to the present via the Data Pool and the EOS Data Gateway (EDG).
Reprocessing of the AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parms, & QC EASE-Grids (AE_Land3) data to correct problems in the structural metadata is completed. Spatial subsetting of AE_Land3 is again available through the EOS Data Gateway.
Spatial subsetting of the AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parms, & QC EASE-Grids (AE_Land3) products will be unavailable until further notice, due to the B02 data containing errors in the structural metadata. Users are advised that any geolocation function or software that uses the HDF-EOS library will return erroneous results. The affected data are currently being reprocessed to correct the metadata problem. We apologize for any inconvenience this may cause our customers. Please contact NSIDC User Services for more information ( nsidc@nsidc.org ).
Reprocessing has begun for AMSR-E/Aqua L1A Raw Observation Counts (AMSREL1A) data back to the start of the AMSR-E mission. Data will be reprocessed to Version 2 (V002) beginning with data from 18 June 2002 forward to 1 March 2005, when the Version 2 algorithm was implemented. Data will be available via the Data Pool and the EOS Data Gateway (EDG) as they are reprocessed, which will take several months to complete.
On 01 March 2005, the AMSR-E/Aqua L1A Raw Observation Counts will be produced with a Version 2 algorithm, which features corrections to the cold sky mirror (CSM) data, a geometric correction, and minor format changes.
At the same time, the AMSR-E/Aqua L2A Global Swath Spatially-Resampled Brightness Temperatures (Tb) will be produced with the B04 algorithm, with the following features:
The AMSR-E rain products AE_Rain and AE_RnGd stopped production on 04 November 2004, while the algorithm developers modified the production code following the AMSR-E 89 GHz-A feedhorn failure in early November. The Level-2B rain product AE_Rain resumed production on 21 January 2005 (00:08 UTC). File names have a B04 identifier. AE_RnGd is a monthly product so new data files will not arrive until approximately mid-February.
The Level-2A brightness temperatures product AE_L2A and all higher-level products, except for AE_Rain and AE_RnG, are no longer being produced with the B02 algorithm as of 02 January 2005. These products resumed on 06 January with the B03 algorithm, which offers improved calibration because the coefficients no longer depend on SSM/I or TMI. Data are also closer to real time. AE_L2A continues to derive data from the AMSR-E 89 GHz-B feedhorn because of problems with the 89 GHz-A feedhorn. Algorithm developers for the rain products stopped data production on 11 November 2004 because of these problems. They are currently modifying their production code and will release data with improved rain algorithms in the near future.
For more information about the different algorithms and their corresponding temporal coverage, see AMSR-E Data Versions.
The AMSR-E 89 GHz A-horn developed a problem on 04 November 2004. Data from this horn are no longer valid. The AMSR-E algorithm developers are planning the following changes to accommodate this data loss:
Starting 11 November, a revised Level-2A processing algorithm, which uses only the 89 GHz B-horn data, will be used to produce the Level-2A product; and the file names for Level-2A will go from B01 to B02.
The Level-2B and Level-3 rain products will not be produced from 04 November until mid-December while the algorithm developers modify the production code. Thus, in mid-December, upon this algorithm change, the rain file names will go from B03 to B04.
The Level-3 snow and sea ice processing algorithms will not be revised in light of this instrument problem because the Level-2A input to these algorithms is being modified so that it uses only 89 GHz B-horn data. The Level-3 snow and sea ice file names will not change as a result of this problem.
The Level-2B and Level-3 soil moisture and ocean products are not affected by the loss of 89 GHz A-horn data.
Reprocessing of the Level-2A product and Level-2B and Level-3 rain products will have the following implications for users:
The AMSR-E SIPS has completed the first historical processing of the AMSR-E data for June 2002 (beginning of mission) through February 2004. The complete set of AMSR-E data products from beginning of mission to the present is now available at the NSIDC DAAC. For several of the AMSR-E data products, the science processing algorithm was updated in May 2004, several months after public release of the data. The AMSR-E SIPS is now reprocessing these data from March 2004 - May 2004 to create the following replacement products: level 2 rain and level 3 sea ice, snow, and rain. This will create a consistent dataset using the same algorithms for the entire period of June 2002 - May 2004. We expect this activity to be completed by late November. The products will then be available at the NSIDC DAAC.
Users can now request subscriptions for AMSR-E, ICESat/GLAS, MODIS, and NISE data. This option is convenient if you require new data for a specific region on a daily or other repeating basis, but you do not want to actively search and order data files each time. Based on your preference, NSIDC will either push new data to your local server via File Transfer Protocol (FTP) or will stage data on our FTP site for you to pull. Please see Data Subscription Requests for more information.
On 12 May, NSIDC began distributing the following products with improved algorithms:
AE_Rain
AE_RnGd
AE_SI6
AE_SI12
AE_SI25
AE_DySno
AE_5DSno
AE_MoSno
Details of the algorithm update are still unknown; more information will be available soon. Data files with improved algorithms have B02 in their file names. B indicates beta product maturity where data are calibrated by the Japan Aerospace Exploration Agency (JAXA), Contractor: Mitsubishi Electric Corporation, in producing input Level-2A brightness temperatures. The product maturity will eventually upgrade to validated after the science software is tested and the algorithm is validated using the official NASA calibration.
These B02 products are currently being processed back to 18 June 2002, the start of the mission.
The First Workshop on Earth Observing System (EOS) Snow and Ice Products will be held near Goddard Space Flight Center in Greenbelt, Maryland, on 16-17 November 2004. The intent of the workshop is to bring together current and potential users of EOS snow and ice standard products from the Moderate-Resolution Imaging Spectroradiometer (MODIS), Advanced Microwave Scanning Radiometer - EOS (AMSR-E), Ice, Cloud and land Elevation Satellite (ICESat), Enhanced Thematic Mapper Plus (ETM+), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors. The themes of the workshop center on the snow and ice products including validation results, integration of EOS snow and ice products into models, production of climate data records, and the discussion of improvements to data access and availability. Presentations by data producers will be made, and demonstrations dealing with the acquisition and use of the products will be provided by the National Snow and Ice Data Center (NSIDC) and the Goddard Distributed Active Archive Centers (DAACs). All users of EOS data are invited to present posters on their snow- and ice-related results. There will be ample time during the workshop for discussions relative to the workshop themes. If interested, please contact Dorothy Hall at NASA/GSFC or Marilyn Kaminski at NSIDC.
Steven Chan of NASA's Jet Propulsion Laboratory used AMSR-E soil moisture data to quantify the extent of flooding after a large-scale thunderstorm ripped through the midwestern U.S. in March 2004. Read more about this study here.
The monthly AMSR-E products listed below are available from NSIDC, with data dates starting 01 March 2004. See Ordering AMSR-E Data from NSIDC for more information.
AMSR-E/Aqua Monthly L3 Global Ascending/Descending .25x.25 deg Ocean Grids
AMSR-E/Aqua Monthly L3 5x5 deg Rainfall Accumulations
AMSR-E/Aqua Monthly L3 Global Snow Water Equivalent EASE-Grids
Level-2B and Level-3 daily and weekly products are available from NSIDC. See Ordering AMSR-E Data from NSIDC for more information. Other products will be available soon:
April 2004:
AMSR-E/Aqua Monthly L3 Global Ascending/Descending .25x.25 deg Ocean Grids
AMSR-E/Aqua Monthly L3 5x5 deg Rainfall Accumulations
AMSR-E/Aqua Monthly L3 Global Snow Water Equivalent EASE-Grids
The new AMSR-E data tool developed at NSIDC and introduced at the AGU meeting in December 2003 is now available. The AMSR-E Swath-to-Grid Toolkit (AS2GT) is a suite of software tools distruted with NSIDC's Passive Microwave Swath Data Tools (PMSDT) to subset and grid Levels 1B and 2A AMSR-E swath data. AS2GT makes it possible to quickly and easily work with the AMSR-E data in ways that may not be available in the standard gridded data sets. This toolkit allows you to process data into custom grids with whatever temporal or spatial resolution you require. AS2GT maintains the highest data quality for your application by giving you control over map projection, number of samples per day, input resolution and interpolation method.
The following is from Bill Guit, EOS Aqua Mission Director:
To users of Aqua data who need the predicted ephemeris in their processing:
On Wednesday, December 10, the Aqua Flight Dynamics System (FDS) experienced multiple drive failures on its operational RAID. After diagnostics were run, it was determined that three of the eight drives were bad. Due to the number of drive failures, the RAID was unable to repair itself with a simple drive replacement and the system was declared inoperable. Hardware problems with the FDS backup RAID (one bad drive) and difficulties encountered in populating the RAID with backup files resulted in it being declared inoperable also. This left the FDS unable to generate its routine products, including the daily ephemeris load that gets sent to the spacecraft..... By Friday afternoon, December 12, Dell technicians had replaced the failed hardware on both systems and had started the process of restoring the operational software and data files to the system.
As of late Sunday, December 14, the FDS was restored to normal operations. Please let us know if the problem had an impact on your normal operations. We apologize for any inconvenience this may have caused some of you.
The Earth Observing System (EOS) Science Working Group on Data (SWGD) is announcing a workshop scheduled for 5-6 November 2003, in Greenbelt, MD, USA. This workshop will include panel and breakout discussions by users describing their objectives, type of data they need, access to data, and barriers encountered and overcome. Please visit the SWGD's workshop announcement for more information.
AMSR-E/Aqua L1A Raw Observation Counts are available from NSIDC, with data beginning 19 June 2003. AMSR-E Level 1A observation counts are processed from Level 0 science packet data by the Japan Aerospace Exploration Agency (JAXA) Earth Observation Center (EOC) in Japan. Each half-orbit data granule consists of observation counts, antenna temperature coefficients, offsets for calculating antenna temperatures, calibration temperature counts, land/ocean flags, time, latitude, longitude, and navigation fields in HDF format. AMSR-E Level-2A data will be available on 01 September 2003, and other products will be available in March 2004.
The NASA Goddard Space Flight Center's Special Project Initiatives (SPI) office will host a webcast of AMSR-E validation experiments on 27 March 2003. With an Internet Explorer browser, click on the RESOkit link where you will be directed to a sign-in page to create an account first. Click on the small lightning bolt icon for the webcast page. You must have Windows Media Player freeware installed on your computer to view the webcast.
The Aqua satellite is among several remote sensing platforms to collect snow cover data for the Cold Land Processes Field Experiment (CLPX). Jointly sponsored by NASA and NOAA, CLPX researches landscapes where water is frozen either seasonally or permanently. Data collected at the surface and from aircraft will be compared to snow cover data from the AMSR-E instrument aboard Aqua to validate the accuracy of the satellite data. Read more about the research in the NASA Press Release.
AMSR-E recently obtained images of Arctic and Antarctic sea ice extent showing changes from 2-4 June and 21-22 July 2002. See the latest images on the NASA Earth Observatory site.
First-light images from AMSR-E include microwave observations of a typhoon on 4 July 2002, sea surface temperature through clouds, and color global composites of brightness temperatures for 2-4 June 2002. See the images on the JAXA Web site.
NASA's Aqua satellite successfully launched on 4 May 2002. The Aqua mission will collect information about the Earth's water cycle. NSIDC will archive and distribute science products from the AMSR-E instrument aboard Aqua. Visit NASA's Aqua Web site for more information.
See also: AMSR-E Validation Data
