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The second progress meeting of ELDAS, held at INM in Madrid on December 10-11, 2003, focused on advancements for the MARS archive related to meteorological data management. Key topics included the introduction of new ELDA classes, experimental version tracking, data archival strategies, and the integration of forcing fields produced outside ECMWF. Discussions encompassed daily precipitation data handling, the use of atmospheric fields from ECMWF, and strategies for data re-projection and storage, aiming to enhance accessibility and usability for meteorological research and applications.
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MARS storage issues Pedro Viterbo European Centre for Medium-Range Weather Forecasts ELDAS 2nd Progress Meeting INM, Madrid, 10-11.12.2003
GRIB for MARS archive • General remarks: • New Class for ELDAS: Number 8, Mars mnemonic ‘el’ • Different experiment versions identified by EXPVER final version (EXPVER=1) • Different productions of the same variable (e.g. soil moisture, precipitation) identified by ‘’STREAM’’ • Forcing fields produced outside ECMWF: • TYPE=34 (‘’gridded observations’’) • Data should be saved from N S and W E • Parameter numbers: Code table 128, plus new code table (specific to ELDAS) • Grid 0.2 x 0.2 (or multiplies of it), ELDAS orography • Data producer should: • provide sample routines to read the data • provide data grib coded via ftp fine tuning of grib code (i.e. header changes) can be performed before putting the data into MARS
Precipitation in Mars • Streams (parameter number= 228): • Daily fields (06UTC- 06UTC) derived from gauge data • Daily fields (06UTC- 06UTC) derived from gauge + radar data • Daily precipitation errors ( filled with 24h forecasts) (TYPE=13) • 3-hourly disaggregated fields (based on forecast) • SW+LW radiation: • Bit-mapped • Parameter number: SW:169, LW:175 • 3-hourly
Other forcing fields • Heating rates: • Strange fields for MARS: • Suggestion to store 4 fields: • Delta T • flag • Initial time UTC (HHMM) • Final time UTC (HHMM) • Meteorological background field from ECMWF: • 2T, 2Q/RH, 10U/V, advection , … • 2m-T interpolated and adjusted via lapse-rate to ELDAS orography • 2m-RH no adjustment • Based on t511/60 level data from 12-36 hour forecasts from 12 UTC: • 30 Sep 1999 – 31 Aug 2000: Starting from ERA40 159/60 level initial conditions • 1 Sep 2000 – 19 Nov 2000: 12-36 hour from t511 esuite • 20 Nov 2000 – 31 Dec 2000: Operations • All forecasts with 3-hourly post-processing, to disaggregate precipitation • Spherical harmonics data projected to reduced gaussian grid and then interpolated to 0.2 deg • Based on ECMWF orography
Production output fields • Production output fields from outside ECMWF: • Data source identifier: originating centre • Sub-centre identifier: 98 (ECMWF) • 0.2 x 0.2 grid
Archival for DWD • MARS will NOT archive fields in two representations (rotated lat-lon and lat-lon) • Two possibilities • Archive rotated • DWD will be able to reuse the data in a straightforward manner + • Anyone else will have to go through a transformation to get lat-lon - • MARS utility for re-projection to be developed - • Archive lat-lon • DWD will have to rotate (and rotate/un-rotate will not get back original field) - • (DWD could separately store rotated initial fields in, e.g., ecfs) • Anyone else will use the data directly + • MARS utility to rotate to be developed (?) -
