The Radio Occultation Processing Package
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Transcript of The Radio Occultation Processing Package
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The Radio Occultation Processing Package
GRAS-SAF Team (Axel von Engeln), August 2005
GPSRO2, Lansdowne, Virginia
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Introduction
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ROPP Objectives
To provide users with a comprehensive software package, containing all necessary functions to pre-process RO data from CGS Level 1b files or GRAS SAF Level 2 files, plus RO-specific components to assist with the assimilation of these data.
Implemented as a set of pick’n’mix modules. Some 3rd party freeware support libraries required (e.g. netCDF, udunits, Lapack)
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ROPP Background
Partly follows the AAPP idea (ATOVS and AVHRR Pre-processing Package / NWP-SAF)
Developed within the GRAS-SAF at the Met Office
Aims at Operational Meteorological Centers
Also allows stand alone processing
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ROPP Context
GRAS Level 1b (CGS)
PFS netCDFpfs2ropp
GRAS Level 2 (SAF)
ropp2bufrBUFR
ropp_1dvar
ropp_fm
NWP VAR system
NWP User
netCDFropp_preproc
ropp_qc
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ROPP Facts
Portability built-in (tested with several Unix/Linux compilers)
Installation uses standard configure, make, make install sequence
Maintained under SVN version control ROPP is NOT a black box, standalone,
end-to-end processor but a modular system providing the required (possibly distributed) functions.
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Modules
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ROPP Modules (1)
ropp_tools Utility Library (unit conversions, interfaces etc)
ropp_io IO Library (bufr, netCDF, conversions)
ropp_fm Forward Library, T/L & Adjoints for bending angles
or refractivity (hybrid, pressure & height based)
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ROPP Modules (2)
ropp_1dvar 1DVar Library (Minimiser, Q/C)
ropp_ug User Guide
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ROPP Future Modules
ropp_preproc Pre-processing Library from Level 1b to Level 2
(Version2: Abel transform, thinning, coordinate transforms, Version3: FSI)
ropp_qc Quality control Libraries
ropp_fm 2-D Bending Angle (hybrid, pressure & height
based)
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ROPP Examples
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ROPP Examples: Information content
Tropical profile, w/ and w/o inflated background errors above 5 hPa, for various uncorrelated bending angle noise levels
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ROPP Examples: 1K Altitude
One order of magnitude in noise reduction ~ 15 km in altitude.
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ROPP: Surface Pressure Retrieval
Surface pressure retrieval increments. Small inconsistency in altitude reference (top) and modified (bottom).
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Acknowledgments / Contacts
Acknowledgments:
•Met Office (Dave Offiler)•Met Office / EUMETSAT (Christian Marquardt)•Met Office / ECMWF (Sean Healy)
Contacts:
•Email: [email protected]•Web: http://www.metoffice.gov.uk/research/interproj/grassaf/index.html
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Questions & Answers