Table of Contents
I get the error 'Requested data is on one or more damaged tape: ...'. What can I do?
If you see this error please contact us, providing the MARS output showing the data requested and the error message. In most cases the data needs to be restored and the complete MARS output allows us to identify the relevant files and tapes.
What can I do if my retrieve request fails with 'data not found'?
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If the reason to construct a loop around a MARS request is the desire to write the output to multiple target files try to use the multi-target feature whenever possible.
I cannot retrieve recent Initialised Analyses. Why?
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Retrieved data can of course be manipulated in any way outside MARS, e.g. using Fortran programs. Python scripts etc. To users with less programming experience some tools available at ECMWF might be of particular interest:
The GRIB ecCodes package offers handy tools to examine the content and to manipulate GRIB files on the command line.
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offers a GUI to some functionality of GRIB APIecCodes's examination tools.
CDO is a collection of Climate Data Operators, including, e.g. vertical interpolation, which can by applied to meteorological fields in various formats, including GRIB. This tool box is installed at ECMWF but has been developed and is maintained by MPI, Hamburg. Please direct all queries to them. For more details refer to the CDO home page.
Various tools are available to convert GRIB to netCDF.
Metview also provides an examiner for BUFR data, which can be started on ecgate as
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Observations are archived in MARS with 2 days delay. As a rule of thumb, you can always access date = -3, as the time at which observations archiving is carried out may vary from day to day depending on suite schedule. Please also note that observations are not generally accessible.
How can I compute the accumulation using data from the overlap stream?
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A sample MARS request to compute the 48-hour accumulation of total precipitation from T1 = 216 h to T2 =264 h, on a 0.5/0.5 regular lat/lon grid where the truncation time step is 240 looks like this:
RETRIEVE, CLASS = OD, GRID = 0.5/0.5, |
If accumulations across the resolution change are computed as above, spurious negative accumulations are very rare.
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Note: Since implementation of cycle 48R1 at the 06 UTC run on 27 June 2023, the resolution of both medium-range ensemble(ENS) and extended-range ensemble (ENS extended) no longer varies over the forecast period, streams efov, efho, weov and ewho, providing ensemble forecast overlap fields, is discontinued.
More FAQs
You can also find some MARS related FAQs on www.ecmwf.int. For FAQs reg. Reanalysis datasets (e.g. ERA-Interim) please also have a look at the Copernicus Knowledge Base.