Combining NCEP 1 degree & 2.5 degree grib data

[Craig Arthur]

Hi all,

I am attempting to combine the accumulated precipitation fields across two
grib resolutions from the NCEP GFS. The gribs to +180 hours are 1 degree and
for +192 onwards are 2.5 degree (these are from
ftpprd.ncep.noaa.gov/pub/data/nccf/com/gfs/prod).

Using regrid2 I can generate 2.5 degree data from the +180 grib, starting at
a given lat/lon.

ga> define precip = regrid2(apcpsfc,-2.5,-2.5,ba,100,-45)
(The lat/lon bounds are the bounds of the grib file I'm using)

When I combine the new 2.5 deg +180 forecast data with the standard (2.5
deg) +192 grib data, all values are returned as undefined.

Is this something that has been done before and if so, how was it done?

Alternatively, if someone could point me in the direction of a uniform
resolution grib dataset right through the GFS run, I would be very grateful.



Craig Arthur
Computer Modelling, Meteorologist
The Weather Company
Level 1/7 West Street
North Sydney, NSW 2060
Ph:  +61 2 9965 9258
Mob: 0409 779 478
Fax: +61 2 9955 1536
Email: carthur at theweather.com.au