Data Versions for V001

Though NSIDC no longer distributes AMSR-E Version 1 (V001) data products, the following information is available to users who may continue to require support for these data. This Web page details the AMSR-E V001 processing and algorithm history for the validated version of each V001 data product. It also supplies a temporal coverage table by algorithm. To access this information for Version 2 (V002) data products, visit the Data Versions for V002 Web page.

This Web page is divided into the following categories:

File Naming Conventions
V001Processing and Algorithm History
V001 Temporal Coverage Table by Algorithm

File Naming Conventions [top]

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 represent 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.

V001 Processing and Algorithm History [top]

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

AE_L2A:

B01: Original at-launch version of data.

B02: Corrects problems with the AMSR-E 89 GHz A-feedhorn by producing data from the 89 GHz B-feedhorn only.

B03: 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.

B04: Changes to this algorithm include:

The name of the unsampled elements changed from Level1B to not-resampled.
Degree units are more consistent, for example, deg rather than deg. for both angle and temperature.
Level-2A metadata include CoRegistrationParameterA1 and CoRegistrationParameterA2 fields.
Position_in_Orbit was written as an 8-byte number rather than 4-byte.
Data include new fields for geostationary satellite glint and effective cold target temperature.
The ProcessingVersionNumber swath attribute was eliminated.

B05: Changes to this algorithm include:

Improved geolocation.
Increased Earth Incidence angle to two bytes.
Augmented the Scan_Quality_Flag with a spin rate flag and a flag indicating when observations are not all on the Earth.

B06: Corrected rounding error in the RangeEndingTime swath attribute and metadata item.

B07: The purpose of this algorithm is to:

Correct the earth incidence angle calculation to correct for instrument roll.
Modify along-scan antenna temperature adjustment using the new roll angle.
Correct geolocation errors.
Update the resampling weights of the 6.9 and 10.6 GHz channels.
Recalibrate the hot load and revise the method for computing the effective hot load temperature.
Introduce a flagging algorithm for RFI from European Geostationary TV satellites.
Correct for the August-September 2003 Aqua pitch error.
Correct for lunar radiation entering the cold mirror.
Match the 89A and 89B observations when doing resampling.
Use UT1 time to compute Earth rotation angle for geolocation accuracy and to avoid discontinuity in the geolocations parameters when a leap second occurs.
Assign units, scale factor, and offset to all data fields.
Modify swath attributes and data arrays.

AE_Land:

B01: Original at-launch version of data.

B02: Changes to this algorithm include:

The number of pixels per scan changed from 196 to 243 (the full swath width).
Updated land and surface type classification parameters and regression parameters.
Updated brightness temperature quality assessment to prevent out-of-bounds brightness temperatures from being gridded.
A new frozen ground classification.
Using the difference of the 10.6V GHz and 18.0V GHz as the only criteria for defining Radio Frequency Interference (RFI). If the difference is greater than or equal to 5.0, the pixel is flagged as contaminated with RFI.
Upgrades to the surface type classification to indicate combinations of surface types.

B03: Minor modification to the soil moisture QC within the science code.

B04: Update L2A reader for version 5 L2A.

B05: Updates to accommodate the L2A version B07 format changes.

AE_Land3:

B01: Original at-launch version of data.

B02: Input Level-2B product uses full swath (243 pixels). Combines Surface Type and Inversion QC Flag 1 from the Level-2B product to form the Inversion QC Flag field.

B03: Corrects structural metadata error, introduced in B02, in which the corner coordinates were incorrectly expressed in degrees. This caused any geolocation function or software that used the HDF-EOS library, including spatial subsetting via the WIST, to return erroneous results. In B03, the corner coordinates are properly expressed in meters.

B04: Accommodates L2 Land transitional file input.

AE_Ocean:

B01: Original at-launch version of data.

B02: Updated the L2A reader in preparation for version B04 L2A.

B03: Changes to this algorithm include:

A salinity correction.
A more sophisticated post hoc correction for anomalies.
RFI identification and flagging.
An update to the L2A reader to accommodate version 5 L2A format.
Use of full swath.
A new flag added to the ocean_products_quality_flag array to identify geostationary satellite RFI.
Detection of sea ice using the NASA Team Sea Ice Algorithm.
The redefinition of default values in arrays to eliminate ambiguity.
The addition of units for all fields.
Updates to the quality flags.

B04: Updates to accommodate the L2A version B07 format changes.

AE_DyOcn, AE_WkOcn, and AE_MoOcn:

B01: Original at-launch version of data.

B02: This algorithm uses full swath, which includes the addition of units for all parameters and excludes observations that meet any of the following conditions:

The TB ice flag and the climate ice flag indicate the presence of ice.
Contamination by sun glint or RFI.
L2B ocean parameter(s) out of bounds.
Suspect L2B ocean quality flags.

AE_Rain:

B01: Original at-launch version of data.

B02: First public version of data. The number of pixels per scan changed from 392 to 486 (the full swath width).

B04: Corrects errors resulting from the AMSR-E 89 GHz-A feedhorn failure. The number of pixels per scan changed from 468 to 392.

B05: Improves low coastal rain rates.

B06: Rain rate is now calculated for surface types of "possible ice over coast."

B07: Update L2A reader for version 5 L2A.

B08: Updates to accommodate the L2A version B07 format changes.

AE_RnGd:

B01: Original at-launch version of data.

B02: First public version of data. Modified the L2B Rain rate product reader so that the full swath width of the L2B product can be used. Updated to prevent any missing data from being counted in the L2B histogram

B03: Corrects low tropical coastal rainfall retrievals and modifies calculations of cold season coastal rainfall estimates to eliminate false rain signatures, which also eliminates most true rainfall signatures for this condition. The algorithm also eliminates rainfall retrievals over ocean when the sun glint is greater than 20 degrees. In only AE_RnGd, the B03 algorithm lowers the upper limit for acceptable brightness temperatures over ocean and corrects minor errors in the processing code.

B04: Updates to L2A reader for version B05 L2A.

B05: Updates to accommodate the L2A version B07 format changes.

AE_SI6, AE_SI12, and AE_SI25:

B01: Original at-launch version of data.

B02: First public version of data. The following B02 algorithm changes apply only to data derived from the Bootstrap sea ice algorithm:

Uses the full swath.
Updates emissivity values based on date.
Updates intercept parameters used in line-fitting routines.
Adds 37H GHz to the argument list for Southern Hemisphere routines.
Eliminates overlapping scans between passes.
Updates weather filter parameters.
Updates brightness temperature tie points for ice concentration.

B03: The following B03 algorithm changes apply only to data derived from the Bootstrap sea ice algorithm:

Uses the 37H GHz channel in the sea ice concentration algorithm.
Updates emissivity values.
Significantly updates the bootstrap sea ice concentration algorithm.
Adds brightness temperatures to threshold checks.
Modifies the brightness temperature upper limit value from 350 K to 320 K.

Also, a known issue exists in this version. In the HDF-EOS structural metadata, the eccentricity squared projection parameter is rounded to only four significant digits, whereas the program actually uses a value with seven significant digits (0.006694 vs. 0.006693883).

B04: This algorithm adapts to the B04 L2A format changes.

B05: This algorithm includes:

Incorporation of the TLSCF L2A B05 reader.
Calculation of Southern Hemisphere parameters based on the NASA Team 2 algorithm instead of the Bootstrap algorithm.
Modification of difference arrays in Southern Hemisphere; all difference arrays now reflect the difference in the Bootstrap algorithm from the stored NASA Team 2 algorithm.
Updates to error reporting.
Updates for local only Global Hydrology and Climate Center Science Investigator-led Processing System (GHCC-SIPS) HDF-EOS version 2.13 grid API (GDapi.c) to store the eccentricity squared projection parameter to 9 decimal places in the structural metadata.

B06: Updates to accommodate the L2A version B07 format changes.

AE_DySno, AE_5DSno, and AE_MoSno:

B01: Original at-launch version of data.

B02: First public version of data. SWE values were reduced by a factor of two to correct for an over-estimation of SWE. The number of pixels per scan changed from 196 to 243 for these three products.

B03: This algorithm:

Contains ancillary file updates.
Uses satellite attitude information.
Adds brightness temperature limit checks.
Eliminates checks for rain, cold rain, and wet snow.
Eliminates explicit definition of xdim and ydim in the grid setup.

B04: This algorithm adapts to the B04 L2A format changes.

B05: This algorithm includes:

Updates to the forest cover ancillary files. Two MODIS products are now used to help correct for forest attenuation.
The daily product retrievals are now performed on the AMSR-E individual T_b samples, which are then averaged to the EASE-Grid 25x25 km Northern and Southern Hemisphere projection grid.
Retrievals are calibrated for snow depth with a snow density climatology file used to convert snow depth to Snow Water Equivalent (SWE).

B06: Updates to accommodate the L2A version B07 format changes.

B07: Added the scale factor attribute to Snow Water Equivalent arrays.

V001 Temporal Coverage Table by Algorithm [top]

Table 2 defines the temporal coverage for each AMSR-E data product. In Table 2, 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 V002 Temporal Coverage Table.

**Table 2.** V001 Temporal Coverage Table
	B01 algorithm	B02 algorithm	B03 algorithm	B04 algorithm	B05 algorithm	B06 algorithm	B07 algorithm	B08 algorithm
AMSREL1A	2002-06-22 (00:11) to 2005-03-01 (00:14)
AE_L2A	2002-06-18 (23:40) to 2004-11-04 (00:46)	2004-11-04 (00:46) to 2005-01-02 (00:27)	2005-01-02 (00:27) to 2005-03-01 (00:14)	2005-03-01 (00:14) to 2005-08-15 (10:13)	2005-08-15 (10:13) to 2005-09-28 (05:41)	2005-09-28 (05:41) to 2006-03-21 (04:16)	2006-03-21 (04:16) to 2006-08-01 (00:29)
AE_Land	2002-06-18 (23:40) to 2005-02-09 (22:05)	2005-02-09 (22:04) to 2005-06-29 (04:21)	2005-06-02 (23:37) to 2005-08-25 (00:57)	2002-06-18 (23:40) to 2006-03-10 (09:31)	2006-03-10 (09:31) to 2007-04-19 (21:25)
AE_Land3	2002-06-18 to 2005-02-22	2005-02-15 to 2005-09-05	2002-06-18 (23:40) to 2007-04-19 (12:49)	2007-04-19 (00:42) to 2008-07-06 (00:24)
AE_Ocean	2002-06-18 (23:40) to 2005-02-07 (23:56)	2005-02-07 (23:56) to 2005-08-23 (04:27)	2005-08-23 (04:27) to 2006-03-10 (09:31)	2006-03-10 (09:31) to 2007-05-09 (02:52)
AE_DyOcn	2002-06-18 (23:40) to 2005-08-19 (12:44)	2005-08-19 (12:44) to 2008-07-06 (00:24)
AE_WkOcn	2002-06-18 (23:40) to 2005-08-14 (12:26)	2005-08-14 (12:26) to 2007- 2008-07-06 (00:24)
AE_MoOcn	2002-06-18 to 2005-08-23	2005-08-23 to 2008-07-06 (00:24)
AE_Rain		2002-06-18 (23:40) to 2004-09-24 (14:04)	2004-09-24 (14:04) to 2004-11-04 (00:46)	2004-11-04 (00:46) to 2005-04-01 (04:28)	2005-04-01 (04:27) to 2005-07-06 (04:28)	2005-06-02 (04:28) to 2005-08-23 (04:27)	2005-08-23 (04:27) to 2006-03-10 (09:31)	2006-03-10 (09:31) to 2006-11-13 (02:58)
AE_RnGd		2002-06-18 to 2004-11-01	2004-11-01 to 2005-08-25	2005-08-25 to 2006-03-01 (00:33)	2006-03-01 (00:33) to 2008-07-06 (00:24)
AE_SI6		2002-06-18 (23:40) to 2004-09-24 (00:03)	2004-09-24 (00:03) to 2005-02-25 (00:39)	2005-02-25 (00:39) to 2005-09-05 (00:38)	2005-09-05 (00:38) to 2006-03-16 (00:40)	2006-03-16 (00:39) to 2008-07-06 (00:24)
AE_SI12		2002-06-18 (23:40) to 2004-09-24 (00:03)	2004-09-24 (00:03) to 2005-02-25 (00:39)	2005-02-25 (00:39) to 2005-09-05 (00:38)	2005-09-05 (00:38) to 2006-03-16 (00:40)	2006-03-16 (00:39) to 2008-07-06 (00:24)
AE_SI25		2002-06-18 (23:40) to 2004-09-24 (00:03)	2004-09-24 (00:03) to 2005-02-25 (00:39)	2005-02-25 (00:39) to 2005-09-05 (00:38)	2005-09-05 (00:38) to 2006-03-16 (00:40)	2006-03-16 (00:39) to 2008-07-06 (00:24)
AE_DySno		2002-06-19 (00:29) to 2004-11-28 (00:46)	2004-11-25 (12:15) to 2005-02-25 (00:39)	2005-02-25 (00:39) to 2006-01-14 (12:20)	2006-01-14 (12:20) to 2006-03-16 (00:40)	2006-03-16 (00:39) to 2006-03-31 (00:46)	2006-03-31 (00:46) to 2008-07-06 (00:24)
AE_5DSno		2002-06-20 (00:23) to 2004-11-17 (00:15)	2004-11-22 (00:33) to 2005-02-20 (00:21)	2005-02-20 (00:20) to 2006-01-11 (12:39)	2006-01-11 (12:38) to 2006-03-12 (00:15)	2006-03-12 (00:15) to 2006-03-27 (00:21)	2006-03-27 (00:21) to 2008-07-06 (00:24)
AE_MoSno		2002-06-19 to 2004-11-01	2004-11-01 to 2005-02-01	2005-02-01 to 2006-01-01	2006-01-01 (00:33) to 2006-03-01		2006-03-01 (00:33) to 2008-07-06 (00:24)

Page last updated: 03/10/09