Model Changes:
--Set new thermal roughness length
--Set minimum moisture value in Stratosphere to 1.0x10-7
--Reduce background diffusion in the Stratosphere
Product Changes:
-Correct error in the 192 hr, 12-hr precipitation bucket
-Addition of a new membrane sea level pressure (SLP) field to
the 0.5, 1.0 and 2.5 degree pressure grib (pgrb) files only.
This pressure is generated by first relaxing the underground
virtual temperature and then integrating the hydrostatic
equation downward. The field will be subject to Spectral
Gibsing near the coast, but this will be addressed in a future
implementation.
The three model changes and the 192 hr precipitation change
listed above are designed to address shortfalls introduced
with the 27 July 2010 GFS resolution increase. The issues
being addressed are:
--increased low level warm bias over land
--negative temperature bias in the stratosphere
--negative wind speed bias in the stratosphere
--error in the calculation of the 12 hr accumulated
precipitation at 192 hrs only.
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