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The Radio Occultation Processing Package (ROPP) is one of the deliverables
within the GRAS SAF. This software is developed within the context
of the EUMETSAT Satellite Application Facility on GRAS Meteorology
(GRAS SAF), under the Co-operation Agreement dated 1 December 2006,
between EUMETSAT and the Danish Meteorological Institute (DMI), Denmark,
by one or more partners within the GRAS SAF.
The partners in the GRAS SAF are DMI, Denmark, Met Office, UK,
the Institut d'Estudis Espacials de Catalunya (IEEC), Spain and the European Centre
for Medium Range Weather Forecasts (ECMWF).
ROPP software processes bending angles or refractivity
profiles from radio occultation measurements to temperature, humidity,
pressure, geopotential height profiles. Future development will
also include processing from path delay data to bending angles and
refractivity profiles. For atmospheric profile retrieval, ROPP uses
a 1D-VAR module that allows a variational retrieval of temperature
and water vapour, along with a surface pressure. It is written in
FORTRAN 90, including some extensions of FORTRAN 95. It comes in several
modules which are provided to users of radio occultation data to plug
into their local code together with some stand-alone applications.
The following modules are available.
| Module |
Purpose |
| TOOLS |
Set of utilities used by other ROPP modules |
| IO |
Handles all input output of
radio occultation data, supporting netCDF, text and BUFR formats |
| FM |
Forward model, currently only
1D with future extensions to 2D |
| 1DVAR |
1DVAR code for variational
assimilation, currently on ECMWF model levels |
| QC |
Quality control; currently part of 1D-VAR
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| TEST |
A number of user-runnable tests are included with
most of the above modules.
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The interaction between the different modules is shown in the following
figure, arrows denote dependencies where the arrow head points toward
the module on which it depends.
ROPP also requires several third party libraries to be installed (the latest versions known to be compatible with
ROPP is indicated):
| Library |
Version |
Purpose |
| netCDF |
3.6.1 |
Input/Output of files in netCDF
format |
| udunits |
1.12.4 |
Automatically convert physical
units |
| blas |
3.0 |
Basic linear algebra subroutine
package (required by lapack) |
| lapack/lapack95 |
3.0 |
Linear algebra package/Interface
to Fortran95 |
| m1qn3 |
3.0 |
Minimiser for 1D-Var |
| bufr |
16.5 |
Required if BUFR encoding/decoding is
desired |
| zlib |
1.2.3 |
Compression library (pre-installed on most Unix/Linux OS) |
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ROPP documents
An overview document
(PDF) and the user guide
(PDF) documents are available.
These documents require Adobe Reader
7.0 or later
ROPP Software Request
Users wishing to obtain the ROPP code will need to first register
via the GARF website at the DMI
and then agree to the terms and conditions of a software licence. There is no charge for
the package.
Beta testing
Updates to ROPP will be occasionally issued which users will be invited to test as beta releases
prior to full release. Beta versions will be made available on this page.
There is currently no active beta test programme
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