At GFZ Potsdam the GRACE release 05 (RL05) Atmosphere and Ocean Dealiasing Level1B
(AOD1B) products are generated on a routine basis for the period January 1, 2001
till today (current status December 03, 2017). AOD1B RL05 is used  as all precursor models such as
AOD1B RL04
 for correction of shortterm non tidal atmospheric and oceanic mass
variations for GRACE RL05 gravity products. AOD1B RL04 is based on 6hourly ECMWF
analysis data and output from the baroclinic ocean model for circulation and tides
(OMCT). Details on OMCT RL05 outputs can be found
here. Additionally, for a consistent processing of SLR
data the RL05 time series has been extended back to January 1, 1979 based on ERAInterim data and made available to the users on April, 2015.
All products for 1979 till today are stored as daily gnuzipped ascii files (AOD1B_YYYY_MM_DD_X_05.asc.gz)
at the GRACE archives at ISDC and PO.DAAC and contain spherical harmonic coefficients up
to degree and order 100 for four 6hourly
time stamps (0, 6, 12 and 18 hours) and for each time stamp four different data types
describing gravity variabilities w.r.t. a 2001+2002 mean field are provided:
For an aposteriori correction over land of the two jumps in January 2006 and 2010 (see known issues with AOD1B RL05)
we have defined two new Level2 data sets (called GAE and GAF). They were delivered to the GRACE SDS in terms of technical notes TN08 and TN09 in
April 2014 (available at the GRACE archives at both GFZ and JPL). They have to be applied during the spherical harmonic synthesis in order to generate corrected monthly GSM grids for land applications.
Details on the GRACE AOD1B RL05 products (including GAE and GAF) as well as on the precursor releases can be found in the GRACE AOD1B Product Description Document for Product Releases 01 to 05 (Rev. 4.4, December 14, 2015) which can be downloaded here (1.7 MB).
A typical example for the variability in terms of geoid height for November 1, 2007 00:00 is shown in the following figure.




Figure 1: Geoid height variability [mm] for AOD1B RL05 components "atm", "ocn", "glo" and "oba" on November 1, 2007 00:00.
Quality Parameters
In order to check the quality of the GRACE mission period products different plots are routinely generated.
1. Geoid Height Variability
The minimum, maximum, mean and wRMS (cosine latitude weighted RMS) geoid heigth variability for all four data types and for the complete production period (2001today) is derived from spherical harmonic coefficients of degree and order 0 to 100.
Generally, for a "nominal" AOD1B product, the




Figure 2: Geoid height variability [mm] for AOD1B RL05 components "atm", "ocn", "glo" and "oba" since January 1, 2001.
2. Individual Coefficient Statistics
The individual degree 0 to 2 spherical harmonics 6hourly time series for the "atm", "ocn", "glo" and "oba" variabilities are shown in colour and high pass filtered (after subtraction of the daily mean) in black.
These high pass filtered Cnm and Snm should show no jumps in amplitude.
Interestingly, the atmospheric mass is increasing till 2005 by about 1.9 10^14 kg/year and is then again decreasing till 2008 by about 4.7 10^14 kg/year (see "atm" C00 time series). Since 2008 the mass seems more or less constant. But, as the AOD1B degree 0 and 1 terms are  as for all other background models  not used (fixed to 1 and 0) for GRACE gravity field determination, this does not influence the quality of the GRACE level2 products.
View routinely updated figures for the
degree 0 coefficient
View routinely updated figures for the
degree 1 coefficients
View routinely updated figures for the
degree 2 coefficients