rads

The Radar Altimeter Database System (RADS) was developed by the Delft Institute for Earth-Oriented Space Research, the NOAA Laboratory for Satellite Altimetry, and EUMETSAT. Apart from actual altimeter data, RADS provides here a suite of applications and subroutines that simplify the reading, editing and handling of data from various radar altimeters. Although the actual content and layout of the underlying data products do not have to be identical for all altimeters, the user interface is. Also, the data base is easily expandable with additional data and/or additional corrections without impact to the user interface, or to the software in general. In fact, only in very few cases the software will need to be adjusted and recompiled, in even fewer cases adjustments to the actual tools will be required.

Development

The RADS database and code has gone through various generations. NetCDF datasets were introduced in version 3, while the software more or less stayed the same as in version 2. This new version is a complete rewrite of the code, making it much easier to configure, handle, and expand, and for the first time taking all the advantages of the underlying NetCDF data and the linear algebra provided by Fortran 90.

Documentation

There are two manuals that cover the use of the RADS software and the contents of the RADS data base:

• RADS User Manual
• RADS Data Manual

Requirements

The only requirements to compile and run the code are:

• A unix type environment (Linux, Mac OS X, etc.).
• The make command.
• A fortran compiler (preferrably gfortran, but others like f90, f95, xlf90, xlf95 and ifort are known to work as well)
• The NetCDF library (version 4.3 or later) and together with the Fortran 90 interface and module file.
• Optionally, the git program.
• For downloading and synchronising the data base: the rsync program.

Distribution

Tarballs are released on GitHub 'releases' page.

Bug reports and feature requests

Please submit your bug reports or feature requests, and track existing ones, on the GitHub 'issues' page. To add content will need to sign up to GitHub.

Version History

Following is a history of releases on GitHub, newest to oldest. This does not include explanations of changes to the code that generates the data base.

v4.7.1 (31 Jan 2025)

Version fully supported the ingestion of Jason-3 and Sentinel-6 GDR-G products, though GDR-G is not yet made standard for computing SLA

• rads.xml:
  • Added support for the Jason-3 Second Tandem (Phase j3/c)
  • Added variables for Sentinel-6B.
• Added gdr_f.xml:
  • Confuguration file that forces the standards currently used in RADS, i.e. mss_dtu15, ocean_tide_fes14, and load_tide_fes14; with the current rads.xml there is no effect.
• Added gdr_g.xml:
  • Confuguration file that forces the GDR-G, i.e. mss_hybrid23, ocean_tide_fes22, and load_tide_fes22; use -Xgdr_g on the command line to activate this. In the next version this will become the default.
• rads_fix_s6:
  • Removed applying a bias to HR sigma0 starting from GDR-G, so this will become affective when that data becomes available.

v4.7.0 (24 Jul 2024)

Version with GDR-G variables added, though not yet made standard for computing SLA

• rads.xml
  • Added GDR-G variables mss_dtu21, mss_hybrid23, ocean_tide_fes22, load_tide_fes22
  • Updated OI SST from v2 to v2.1
  • Added JPL GPS orbits (6a and j3)

v4.6.3 (20 May 2024)

• rads.xml:
  • Correct comment for drange_cg
  • Add/update alt_gps orbits for j2, j3, 6a
  • Update orbit info for ERS-1/2 and Envisat
  • Fix add_offset for all SWOT ranges
  • Set new ref_frame_offset* for SWOT (#195)
  • Set proper limits for flag_alt_oper_mode (6a c2 tx pn)
• radsxogen:
  • Correctly report maximum tie interval in xovers (#196)
• Fix handling of if/elseif/else in xml (#197)

v4.6.2 (1 Mar 2024)

• rads.xml
  • Extended SWOT mission back to cycle 102
• Updated configure file using autoconf 2.72

v4.6.0 (15 Feb 2024)

• Documentation
  • made a lot of corrections and updates.
  • removed obsolete variables, indicated deprecated variables slated to be removed.
  • updates to include tx/pn reprocessed data.
  • described better the original data sources.
  • corrected in the tables which data are available for which satellites.
• rads.xml
  • updates to include tx/pn reprocessed (GDR-F) data and removed old tx/pn RGDR data.
  • removed obsolete variables.
  • corrected sat options to correctly identify which data are available for which satellites.
  • added alias tpx for TOPEX.
• Updated config.sub and config.guess

v4.5.2 (20 Oct 2023)

• Documentation
  • replaced name of rads2asc4 by rads2asc; same for other *4 executables.
• rads.xml:
  • updated ref_frame_offset* for JA3 (#180)
  • introduced ref_frame_offset* for S6A (#180)
  • prepared for SWOT Calval and Science Orbits with cycle numbers shifted -300 and +300 respectively to make them time ordered.
  • added all necessary information for SWOT nadir (sw)
  • adaptations for S6A baseline F08 and prepared for baseline F09
  • introduce flag_manoeuvre properfly (#177)
  • update SSB model info for S3A/
  • increase cycle limit for SRAL
  • fix wrong scale on ssb_3d, ssb_3d_adaptive, ssb_adaptive
  • added *_nr variables for 6a
  • updated
• radsstat:
  • allow to compute statistics for the difference between two satellites/missions
  • introduced -c/N, --mean-only, and --groups options
  • do not add attribute coordinates to variables.
  • do not write out phase in ASCII header (#188)
  • extend info in global attributes
• Increased number of characters allowed per option to 640.
• Updated manuals
• Updated config.sub and config.guess
• Corrected flag bit 0 for S6A (#192)

v4.4.0 (27 Apr 2022)

• rads.xml:
  • prepared for Jason-3 Interleaved Orbit (Phase B)
  • align lower limit of range_numval_ku_adaptive with range_numval_ku (for j3)
  • added mss_dtu21 (#174)
  • fix formatting of flag mask of 6a, j2, j3
  • add *_adaptive variables for j3 (#173)
  • update ref_frame_offset for j3 (#178)
  • correct standard_name for mean_wave_period
  • remove ssb_tran2012 from S6A (it was never included in the data files)
  • change limits on sig0 for j3 as result of no longer biasing sig0
  • add mss_comb15
  • update limits for range_numval_ku (6a), range_numval_ku_plrm (3a 3b c2)
  • Update attributes of ssb_cls, ssb_cls_c, ssb_mle3 for JA3 and S6A
  • Removed ssb_hyb from configuration of c2
  • including SARAL GDR-F wave model
• radsstat:
  • improve matching time stamps
  • fix problems (#171)
  • introduced --no-stddev
  • introduce check on collinearity as well as --force and --dt options
  • can now also do differences (along collinear tracks)
  • updated documentation
• radscolin:
  • added --eqtime option
  • option --force: also apply to rogue equator crossing times
  • use inclination to check if missions are collinear
• radsxolist: activated --dual-asc and --dual-des options
• Add MFWAM fields to S3A, S3B, S6A
• Updated manuals
• Updated config.sub and config.guess

v4.3.7 (10 Mar 2021)

• Switch CryoSat-2 (c2) data over from NOAA-generated IGDR to NOP/IOP/GOP products
• Updated config.sub and config.guess
• rads.xml prepared for Sentinel-6A (6a)
• Switch SARAL (sa) data over to GDR-F; Change default ssb for SARAL to ssb_tran2019 (which is what GDR-F does)
• Switch Jason data production over to GDR-F

v4.3.6 (15 Aug 2019)

• rads.xml: Updated ref_frame_offset for JA3 (raise by 1 mm)
• rads.xml: Added ref_frame_offset for S3A/S3B PLRM
• rads.xml: Updated JA2 parameters since coming back on-line on 22-May-2019
• rads.xml: Provide and use GDR-F orbits for CryoSat-2 (alt_gdrf)
• rads.xml: Specified various subphases for sa/b in order to get correct prediction of equator times and longitudes. This solved issue #152.
• Added conf/ntc_only.xml and set latency to 2 (NTC) by default.
• Bug fix: Simple modification of syntax for option parsing check to avoid segfault when compiled with default intel-fc/12.1.9.293.
• New option introduced in radsstat that echoes to stdout fullpath to each pass file checked for data.
• Using -L|--limits on an alias now sets limits of all aliased variables, instead of only the first one.
• Documentation updates.
• Bug fix: Update equator prediction for longitude (not NaN) and using different phases.
• Added command radspassesindex as in RADS3.

v4.3.5 (2 May 2019)

• rads.xml: Added ref_frame_offset_plrm.
• rads.xml: Properly use wet_tropo_rad_plrm instead of wet_tropo_rad for PLRM data.
• rads.xml: Use alt_gdrf for S3A and S3B.
• rads.xml: Added latency variable.
• Properly deal with longitude rollovers in computing means or differences in radscolin.
• Remove insistence that 0-dimension variable (constant) is a double.
• Bug fix: invalid values in RPN data notation may not have always worked correctly.
• Restrict the name of the time dimension to the first word in S%time%info%dataname.

v4.3.4 (2 Apr 2019)

• Bug fix in rads_def_var.
• Small documentation update.
• Allow multiple mission phases with the same name (needed for Sentinel-3B and Jason-2 after geodetic phase rewind).
• Updated Sentinel-3B mission phases.
• Implemented internal tides.
• Removed support for FES2012 tide model.
• Bug fix in rads_add_tide.
• Removed DTU MSS13 from standard models provided.
• Added topo_srtm15plus to alias for topo ahread of removing topo_srtm30plus.

v4.3.3 (19 Nov 2018)

• Added new optional arg