ECMWF Data/GRIBEX update
========================

Contents:
          1. ECMWF model data now on 50 levels
          2. New version of GRIBEX (GRIBEX13)
          3. Decoding GRIB files at the BADC
          4. Vertical Coordinate table of 50 level data


1. ECMWF model data now on 50 levels


On 9th March 1999 the ECMWF model changed the number of levels from 31
to 50.  The extra levels have been added in the stratosphere.  The top
level of the model is now at 0.1hPa.  The new vertical coordinate table
can be found at the end of this mail.


To reflect this change the number of standard pressure levels that the
ECMWF data is held on has increased from 15 to 21.  All of the extra
levels are in the stratosphere.  The 2.5x2.5 lat-lon gridded data
stored at the BADC includes these extra levels.  The set of standard
pressure levels is: 1000, 925, 800, 700, 500, 400, 300, 250, 200, 150,
100, 70, 50, 30, 20, 10, 7, 5, 3, 2, 1 hPa.


To decode the 50 level files you may need to change some of the
parameters determining the size of the GRIB records.  Values that work
can be found in the new version of GRIBEX held at the BADC.


2. New version of GRIBEX (GRIBEX13)


A new version of GRIBEX, software for decoding ECMWF GRIB data, is
available at the BADC.   This new version will
decode all GRIB files held at the BADC.  We have compiled the code on
a Sun and a DEC Alpha.  Other architectures (CRAY, sgi, hp) are also
supported.


The new version of GRIBEX can be fetched from the BADC as a gzipped tar
file.
/badc/ecmwf-op/software/gribex13.tar.gz.


3. Decoding GRIB files at the BADC


The BADC supplies some programs to dump GRIB files as ASCII text.
These programs are simple adaptations of the example program
distributed as part of GRIBEX.  The following programs have been
recompiled with the new version of GRIBEX: grib2txt, grib2fulltxt and
are installed on both tornado and cirrus.  Both programs take a GRIB
file from standard in and output an ASCII dump on standard out.
grib2brief produces a dump of the full GRIB headers, and the first
twenty data values, grib2fulltxt produces a dump of the full GRIB
headers and decoded data, grib2txt produces a dump of an abbreviated
form of the GRIB headers and the decoded data.


In addition some users may have used the programs grib_level_filter,
grib_para_filter, grib2_2.5grid, grib2_n80grid, grib_vod2uv,
grib_vod2uv+vod on cirrus.  These programs are still on cirrus, but
have not been recompiled with the new version of GRIBEX.  They will
still work with GRIB datasets dated before 9th March 1999.  These
programs will only be recompiled with the new version of GRIBEX if
it turns out that there is a demand for them.


4. Vertical Coordinate Table for 50 level data


As:
           0.000000000000         20.006149291992
         43.297805786133         75.346237182617
        115.082153320312        161.897491455078
        215.896911621094        278.005859375000
        350.138183593750        435.562255859375
        539.651367187500        668.615478515625
        828.398925781250       1026.366943359375
       1271.644531250000       1575.537841796875
       1952.054443359375       2418.549804687500
       2996.526611328125       3712.626220703125
       4599.855468750000       5699.113281250000
       6998.386718750000       8507.410156250000
      10181.707031250000      11883.089843750000
      13442.914062500000      14736.355468750000
      15689.207031250000      16266.609375000000
      16465.003906250000      16297.621093750000
      15791.597656250000      14985.269531250000
      13925.519531250000      12665.296875000000
      11261.230468750000       9771.406250000000
       8253.210937500000       6761.339843750000
       5345.917968750000       4050.718750000000
       2911.570312500000       1954.804687500000
       1195.890625000000        638.148437500000
        271.625000000000         72.062500000000
          0.000000000000          0.000000000000
          0.000000000000
Bs:
                                  0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000000000000          0.000000000000
          0.000100360397          0.000672714319
          0.003163340501          0.009292338043
          0.020319156349          0.036974858493
          0.059487640858          0.087894976139
          0.122003614902          0.161441504955
          0.205703258514          0.254188597202
          0.306235373020          0.361145019531
          0.418202280998          0.476688146591
          0.535886585712          0.595084249973
          0.653564572334          0.710594415665
          0.765405237675          0.817166984081
          0.864955842495          0.907715857029
          0.944213211536          0.972985208035
          0.992281496525          1.000000000000


----------------------------


If you have any questions, or need any help using the software, please
feel free to contact the BADC.

BADC Support 06/07/99.