Data Versions for V002

This Web page details the AMSR-E data product Version 2 (V002) processing and algorithm history for the validated version of each data product. It also supplies a temporal coverage table by algorithm. To access this information for Version 1 (V001) data products, visit the Data Versions for V001 Web page.

For information pertaining to major instrument data loss periods, see the Instrument Data Loss Periods Web page.

This Web page is divided into the following categories:

File Naming Conventions
V002 Processing and Algorithm History
V002 Temporal Coverage Table by Algorithm

File Naming Conventions [top]

Identifying Version Numbers in Data Set Titles

Depending on where you order the data from, the version number appears differently at the end of the data set title. For example:

If you order the data from SNOWI or the Warehouse Inventory Search Tool (WIST), the version number is written like this V002 at the end of the data set title: AMSR-E/AQUA MONTHLY L3 GLOBAL SNOW WATER EQUIVALENT EASE-GRIDS V002.
If you order the data from the Data Pool FTP directory, the version number is written like this 002 at the end of the data set title:
AE_MoSno.002.

Product Maturity Codes

AMSR-E products use a Product Maturity Code to designate what version of the algorithm was used to produce the data. These algorithms are identified in the AMSR-E data file names using a Product Maturity Code such as B01, T02, or V03. Refer to the example below.

Example file name: AMSR_E_L3_SeaIce25km_B06_20080207.hdf

Each letter, P, B, T, and V, represents a different stage of the product maturity. Refer to Table 1 for an explanation of these Product Maturity Codes.

**Table 1.** Variable Values for the Product Maturity Code
Variables	Description
P	Preliminary - refers to non-standard, near-real-time data available from NSIDC. These data are only available for a limited time until the corresponding standard product is ingested at NSIDC.
B	Beta - indicates a developing algorithm with updates anticipated.
T	Transitional - period between beta and validated where the product is past the beta stage, but not quite ready for validation. This is where the algorithm matures and stabilizes.
V	Validated - products are upgraded to Validated once the algorithm is verified by the algorithm team and validated by the validation teams. Validated products have an associated validation stage. Refer to Table 3 for a description of the stages.

Validation Stages

A validation stage, such as Stage 1, Stage 2, or Stage 3 may be added to the algorithm Product Maturity Code, for example, V09-Stage3 Algorithm. Table 2 gives the description for each validation stage.

**Table 2.** Validation Stage Descriptions
Validation Stage	Description
Stage 1	Product accuracy is estimated using a small number of independent measurements obtained from selected locations, time periods, and ground-truth/field program efforts.
Stage 2	Product accuracy is assessed over a widely distributed set of locations and time periods via several ground-truth and validation efforts.
Stage 3	Product accuracy is assessed, and the uncertainties in the product are well established via independent measurements made in a systematic and statistically robust way that represents global conditions.

V002 Processing and Algorithm History [top]

This section gives a brief description of the processing and algorithm history of each data product.

AMSREL1A:

This improved version features empirical corrections to the Aqua scan azimuth and satellite flight direction. With corrected sun azimuth, sun elevation, earth azimuth, and earth incidence angles, the geometric accuracy of AMSR-E 89 GHz data improved to within 2 km, compared to Version 1 AMSREL1A data.

AE_L2A:

V08-Stage3: This validated version of the algorithm includes updated global attributes and inventory metadata to reflect a version change from B07 to V08. There were no changes to the science algorithm from B07 to V08.

V09-Stage3: This version corrects the errors in the resampled 89.0 GHz Horizontal data fields (89.0H_Res.#_TB) which were discovered in March 2008. Only V08 files from 19 June 2002 00:29 through 4 November 2004 05:43 contained the bad data. For more information, please see the AMSR-E L2A Brightness Temperatures: Bad Resampled 89 GHz Horizontal Data news brief on the AMSR-E News page.

V10: Changes included in this version are:

Computed a checksum from the latitudes, longitudes, and brightness temperatures. Attached it to the L2A file as a global attribute, and reported it in the QA file.
RSS added the glint angles of the DirecTV 10 and 11 satellites to the Geostationary_Satellite_Glint_Angles field. The low glint angles correlate well with the recent observed RFI artifacts. Over oceans, RFI can be intense: +50 K for 18.7V, and +100 K for 18.7H. Cases this large correspond to low wind conditions with very smooth seas. Initial analysis over land did not reveal significant RFI impacts. The affected period for this RFI is from July 2007 forward.

AE_Land:

T06: Updated the product maturity code status to Transitional (T). There are no algorithm changes from version B05 to T06.

T07: Converted the algorithm code to run on Linux. There were no changes to the science algorithm in this version.

T08: Changed the processing code to produce only a QA file when there is no L2A brightness temperature data qualified for retrieval. There were no changes to the science algorithm in this version. Only being used for reprocessing. T06 is still being used in forward processing.

V09-Stage1: Updated the product maturity code status to Validated. There were no changes to the science algorithm in this version.

AE_Land3:

T05: Changes included in this version are:

Updated the product maturity code status to Transitional (T). There are no algorithm changes from version T04 to T05.
Converted the algorithm code to run on Linux. This version is not compatible with SGI IRIX.

V06-Stage1: Updated the product maturity code status to Validated. There were no changes to the science algorithm in this version.

AE_Ocean:

V05-Stage2: Changes included in this version are:

Updated global attributes and inventory metadata to reflect product maturity change from Beta to Validated.
Improved beamfilling correction to account for different footprint sizes of different frequencies.
A new expression for the rain column height that yields more accurate rain flags is the third byte of the Ocean_products_quality_flag, which identify the proximity and intensity of rain. This is useful for quality assessment of SST and wind speed. The meanings of the rain flags have not changed.

V06-Stage2: Converted the algorithm code to run on Linux. There were no changes to the science algorithm in this version.

AE_DyOcn, AE_WkOcn, and AE_MoOcn:

V03-Stage2: Changes included in this version are:

Updated the product maturity code status to Validated (V). There are no algorithm changes from version V02 to V03.
Converted the algorithm code to run on Linux. This version is not compatible with SGI IRIX.

AE_Rain:

V09-Stage2: This validated version of the algorithm includes updated global attributes and inventory metadata to reflect a version change from B08 to V09. There were no changes to the science algorithm from B08 to V09.

V10-Stage2: Converted the algorithm code to run on Linux. There were no changes to the science algorithm in this version.

AE_RnGd:

V06-Stage2: Changes included in this version are:

Updated the product maturity code status to Validated (V).
Skipped duplicate (overlapping) scans in consecutive L2A files.
Improved L2A brightness temperature binning for monthly ocean grids.
Updated the leap second ancillary file to include the leap second which occurred at the end of 2005.
Converted the algorithm code to run on Linux. This version is not compatible with SGI IRIX.
Added a shell script that is used during installation.
Set the default system stacksize parameter to unlimited.

AE_SI6, AE_SI12, and AE_SI25:

T07: Data never produced using this algorithm version. Algorithm updates included the following:

Updated the product maturity code status to Transitional (T).
Updated the sea ice concentration parameters.
Converted the algorithm code to run on Linux. This version is not compatible with SGI IRIX.
Set the default system stacksize parameter to unlimited.
Added a shell script that is used during installation.
Added new flag values for the 12.5 km snow depth product such as:
- 140 indicates multiyear sea ice
- 150 indicates variability in snow depth
- 160 indicates snow melt.

T08: The AMSR-E sea ice temperature grids were removed from the 25 km product because of inherent ambiguities between changes in the physical temperature of the ice and changes in the ice emissivity. Instead, the panel suggested that an AMSR-E sea ice drift product be developed. Also, this algorithm includes all modifications made in version T07.

V09: A new sea ice version was implemented to validate sea ice. There were no changes to the science algorithm from T08 to V09.The only change was to the file name.

V10-Stage1: Modified the tie point tables for the Antarctic.

V11-Stage 1: Corrected an error in the snow depth over sea ice retrieval in the Southern Hemisphere. This error, introduced in V10, caused snow depth to be overestimated by a factor of about two. AE_SI12 is the only product with the Snow Depth on Sea Ice parameter, but all AMSR-E sea ice products use the same production code and will be processed with the V11 algorithm.

AE_DySno, AE_5DSno, and AE_MoSno:

T08: Changes included in this version are:

Updated the product maturity code status to Transitional (T). There are no algorithm changes from version T07 to T08.
Converted the algorithm code to run on Linux. This version is not compatible with SGI IRIX.
Improved input list error checking.
Set the default system stacksize parameter to unlimited.

V09-Stage1: Changes included in this version are:

Updated the product maturity code status to Validated. There are no algorithm changes from T08 to V09.
Corrected file start/end times in the metadata to accurately reflect only descending orbits.
Removed version numbers from ancillary file names.
Updated the ancillary file Combined_SnowImp_and_LOCI_mask_EASE_Both.

V002 Temporal Coverage Table by Algorithm [top]

Table 3 defines the temporal coverage for each AMSR-E data product. In Table 3, times are reported in UTC (hh:mm), and blank fields indicate the product was never generated with that algorithm.

Note: Use this link to access the V001 Temporal Coverage Table.

**Table 3.** V002 Temporal Coverage Table
AMSREL1A	2005-03-01 (00:14) to present
AE_L2A	V08-Stage3 Algorithm	V09-Stage3 Algorithm	V10 Algorithm
AE_L2A	2002-06-19 (23:40) to 2008-03-07 (00:30)	2002-06-19 (00:29) to 2009-04-16 (04:11)	2002-06-19 (00:29) to present
AE_Land	T06 Algorithm	T07 Algorithm	T08 Algorithm	V09-Stage1 Algorithm
AE_Land	2007-04-19 (21:24) to 2008-07-06 (00:24)	2002-06-19 (00:29) to 2004-07-03 (16:51)	2004-07-03 (16:50) to 2008-12-05 (02:55)	2002-06-19 (00:29) to present
AE_Land3	T05 Algorithm	V06-Stage1 Algorithm
AE_Land3	2002-06-19 (00:29) to 2008-12-01(00:02)	2002-06-19 (00:29) to present
AE_Ocean	V05-Stage2 Algorithm	V06-Stage2 Algorithm
AE_Ocean	2007-05-09 (02:52) to 2008-07-06 (00:24)	2002-06-19 (00:29) to present
AE_DyOcn	V03-Stage2 Algorithm
AE_DyOcn	2002-06-19 (00:29) to present
AE_WkOcn	V03-Stage2 Algorithm
AE_WkOcn	2002-06-19 (00:29) to present
AE_MoOcn	V03-Stage2 Algorithm
AE_MoOcn	2002-06-19 (00:29) to present
AE_Rain	V09-Stage2 Algorithm	V10-Stage2 Algorithm
AE_Rain	2006-11-13 (02:58) to 2008-07-06 (00:24)	2002-06-19 (00:29) to present
AE_RnGd	V06-Stage2 Algorithm
AE_RnGd	2002-06-19 (00:29) to present
AE_SI6	T07 Algorithm	T08 Algorithm	V09 Algorithm	V10-Stage1 Algorithm	V11-Stage1 Algorithm
AE_SI6	n/a	2002-06-19 (00:29) to 2008-09-21(00:44)	2008-09-21 (00:44) to 2009-01-26 (00:03)	2002-06-19 (00:29) to 2009-05-28 (00:41)	2002-06-19 (00:40) to present
AE_SI12	T07 Algorithm	T08 Algorithm	V09 Algorithm	V10-Stage1 Algorithm	V11-Stage1 Algorithm
AE_SI12	n/a	2002-06-19 (00:29) to 2008-09-21(00:44)	2008-09-21 (00:44) to 2009-01-26 (00:03)	2002-06-19 (00:29) to 2009-05-28 (00:41)	2002-06-19 (00:40) to present
AE_SI25	T07 Algorithm	T08 Algorithm	V09 Algorithm	V10-Stage1 Algorithm	V11-Stage1 Algorithm
AE_SI25	n/a	2002-06-19 (00:29) to 2008-09-21(00:44)	2008-09-21 (00:44) to 2009-01-26 (00:03)	2002-06-19 (00:29) to 2009-05-28 (00:41)	2002-06-19 (00:40) to present
AE_DySno	T08 Algorithm	V09-Stage1 Algorithm
AE_DySno	2002-06-19 (00:29) to 2008-12-01(00:02)	2002-06-19 (00:29) to present
AE_5DSno	T08 Algorithm	V09-Stage1 Algorithm
AE_5DSno	2002-06-19 (00:29) to 2008-11-27 (00:27)	2002-06-19 (00:29) to present
AE_MoSno	T08 Algorithm	V09-Stage1 Algorithm
AE_MoSno	2002-06-19 (00:29) to 2008-11-01(00:38)	2002-06-19 (00:29) to present
¹Not all data will be available until reprocessing is complete.

Page last updated: 07/21/09