CSR Release-05 GRACE Level-2 Data Products
Updated: 2015-04-07 (See Note-6)
Thank you for your interest in the latest, Release-05 GRACE Level-2 data products. Users looking for our mean (static) Earth gravity field model may visit the GGM03 web page (http://www.csr.utexas.edu/grace/gravity/); or visit the ICGEM website (http://icgem.gfz-potsdam.de/ICGEM/) for our latest model GIF48, as well as a variety of other mean field models.
This page describes the RL05 time-series of monthly time-variable gravity field estimates. The description on this page is presently intended for users already familiar with the nomenclature and use of GRACE Level-2 data products. Viewers not familiar with these may choose to start instead at http://www.csr.utexas.edu/grace/asdp.html.
As of today (Jan 2, 2014) the CSR RL05 Level-2 data products are available for the span April 2002 through July 2013. The RL05 products for the following months will be delivered as they are produced. The RL05 data products include new GSM, GAC and GAD data products.
NOTE-1 (2012-07-17): We have replaced the CSR-GSM products for the following four months: July-2004; October-2004; March-2005 and February-2006. The GSM products for these four months have been updated with the refined data editing. While the GAC/GAD products for these four months are unchanged, they have been updated as well, for consistency. If you downloaded the data products for these four months prior to July 17, 2012, please download the replacement products. No other products previously delivered are so affected.
NOTE-2 (2014-01-02): GFZ has replaced its entire RL05 GSM product suite by the RL05a product suite. The rationale for this replacement and the pertinent technical details are given in the presentation by Flechtner et al. (click here to download) at the GSTM2013. This presentation is also available through the GSTM link: http://www.csr.utexas.edu/grace/GSTM/past.html. The product suite from CSR and JPL are unaffected.
With the delivery of RL04 data products for April 2012, the older RL04 time-series are now terminated. From May 2012 onwards, all three GRACE Science Data System centers CSR, GFZ and JPL will only deliver the re-processed RL05 time-series.
NOTE-3 (2014-05-08) Degree-96 CSR-RL05 Now Available: CSR RL05 Level-2 data products to spherical harmonic degree 96 for all available months of the mission are now available from the GRACE data archives. A brief characterization of the differences between operational degree-60 fields and the degree-96 fields is given in the technical note CSR-GR-14-01 (this document is also available from the GRACE data archives).
NOTE-4 (2014-05-08) Calibrated Error Standard Deviations for CSR-RL05 Now Available: Calibrated error standard deviations for CSR RL05 Level-2 60x60 degree/order harmonic fields are now available for all available months of the mission from the GRACE data archives. If you wish to examine the full error covariance matrices, please write to email@example.com.
NOTE-5 (2014-10-13): If you downloaded the CSR Release-05 GSM, GAC and GAD files for June 2013 through July 2014 solutions prior to October 6, 2014, please download those files again from the GRACE archives. Due to an error in the handling of the input datasets, the AOD1B de-aliasing fields for the period from June 26, 2013 through July 31, 2014 had to be reprocessed. The daily AOD1B files for this period have been updated. All of the Level-2 data for this duration has been re-processed. The Level-2 fields for the months from June 2013 through July 2014 have been replaced at the PODAAC/ISDC archives. The nature of the error, and their impact on GRACE Level-2 gravity fields are detailed at the GFZ AOD1B Product website and also in the presentations of session A.0 of the 2014 GRACE Science Team Meeting in Potsdam.
NEW NOTE-6 (2015-04-07)The GRACE satellites passed through a 2-day ground-track repeat configuration through the months of Jan-Mar 2015. There is a noticeable increase in the systematic (striping) error in the operational RL05 Level-2 gravity field data product for the month of Jan-2015. Users are advised that they should review their post-processing error reduction techniques in the presence of this error. As an aid to evaluation, along with the standard 60x60 gravity field, an experimental 60x30 field (estimate to degree 60, for all orders less than or equal to 30) is also being made available.
As before, users may access all GRACE data products and documents through PO.DAAC (ftp://podaac.jpl.nasa.gov/allData/grace/L2/CSR/RL05/) or through ISDC (http://isdc.gfz-potsdam.de/grace).
Information Content in RL05 GSM Files:
The information content in RL05 GSM files is the same as in the previous (RL04) GSM files. That is, the RL05 GSM files continue to represent the total gravity variability due to land surface hydrology, cryospheric changes, episodic (earthquake) processes, glacial isostatic adjustment (GIA), and corrections to the background models for atmospheric and oceanic processes. The RL05 GSM products can continue to be used in the same way as RL04 GSM products, with one important exception noted next.
Important Usage Note: The most important difference in usage of RL05 versus RL04 products arises from the fact that the background models for the RL05 processing no longer includes the rates for the C20, C21, S21, C30, and the C40 harmonics. This means that (i) the RL05 GSM files do not contain the GRDOTA cards; (ii) the user does not have to restore these rates when studying secular change; and (iii) the epoch of all harmonics in a GSM file is the middle of the data span used in that solution.
Ancillary Data Products:
For the replacement SLR-derived C20 values, please visit the "Further Details" link below.
Additional regularized GSM product time-series should be available shortly.
Further Details on RL05 Reprocessing
Please revisit these pages for further information.