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Means Operational Pressure Level First-Guess Data Sets
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This part includes a brief description of the Operational Monthly Means Pressure Level First-Guess Data Sets.
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Description :
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period supported - September 1994 to current date;
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each parameter at each level is stored as a field either of grid point values or of spherical harmonic coefficients;
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spherical harmonic coefficients are stored as defined by code figure 1 in tables 9 and 10 of FM 92-IX Ext GRIB.
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data are stored in FM 92 GRIB using sufficient bits to ensure that the values represented can be retrieved to an accuracy consistent with the analysis method used;
The changes to this data set are as follows:
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September 1994 |
Internal data representation is in spherical harmonics with triangular truncation at wave number 213 (T213). Data are short term forecasts from times 0000, 0600, 1200 and 1800 UTC. Forecast step is 006 hours 15 standard pressure levels: 1000, 925, 850, 700, 500, 400, 300, 250,200, 150, 100, 70, 50, 30 and 10 hPa Fields available: geopotential, temperature, vertical velocity, u- and v-components of horizontal wind, relative vorticity, divergence, specific humidity and relative humidity |
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April 1995 |
specific humidity archived on a Gaussian grid (N160) from this date |
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April 1998 |
Internal data representation is in spherical harmonics with triangular truncation at wave number 319 (T319). |
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March 1999 |
Added pressure levels: 20, 7, 5, 3, 2, 1 hPa |
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September 2000 |
Added field ozone mass mixing ratio, archived on a Gaussian grid. Change to 12 hour cycling of 4D-Var; this archive changed to steps 006 and 012 from base times 0000 and 1200 UTC |
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December 2000 |
Internal data representation is in spherical harmonics with triangular truncation at wave number 511 (T511). Gaussian fields are represented on a N256 grid. |
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08.04.2004 |
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