ECMWF/NCEP/etc. Model Links
L. Strow
Updated: Mar 23, 2001
Document URL: http://asl.umbc.edu/~strow/Notes/modelres.html
So far I can't find the definitions for describing the resolution of a GCM model on the web, although it looks as though everyone in the field knows these definitions cold. They all start with Txxx where xxx is some number. Sometimes after xxx there is an L. For example, T213L31 means 213 waves around a great circle with 31 levels between the earth's surface and 30 km altitude. T511, for example, is said to mean a minimum 40 km grid size (see below). Time to find a good book on this stuff.
ECMWF Press Page
This is the only place I could find the present spatial resolution of
the ECMWF model. According to this page,
``ECMWF increased the resolution of its global atmospheric model from T319 to T511 on Tuesday, 21 November 2000. This is roughly equivalent to a reduction from 60 km to 40 km grid size. The resolution of the data assimilation minimization was increased from T63 to T159 on the same date.''I believe the T511 model uses 60 vertical levels, but I'm not sure.
This NCEP link says NCEP is running at T170L42 as quoted here,
``01/24/2000: Resolution upgraded from T126L28 to T170L42, restoring the resolution used from June 15 through Oct 5, 1998. No other changes in the forecast/analysis system. The MRF is run at T170L42 through day 7, then at T62L28 through day 16. The AVN is run at T170L42 out to 84 hours four times a day. (TPB 452)''I think T170 is roughly 0.7 x 0.7 degree, with the lowest pressure layer at 2.0 hPa, and 10 levels above 100 hPa. There are 111.3 km/deg at the equator, so 0.7 degrees is 78 km. (Dia. of earth is 12,756 km). This report details changes to the NCEP operational model in 1998, which is evidently the last big change to the model. NCEP calls their global model either AVN, MRF, or GDAS.model.
ECMWF
model output for the SHEBA column
Use of ECMWF model output for the SHEBA experiment. Evidently they
had some problems with ECMWF changing grid sizes without notification.
ECMWF
resolution discussion
Too old to state current resolution of the ECMWF model.
ECMWF IFS
documentation:
Evidently IFS deals with the observation processing
functions for which field information are required.
ECMWF Data Coverage
Charts
Includes nice downloadable postscript plots of HIRS bias,
variance as a function of time.
National Centers for Environmental
Prediction (NCEP)
NCEP home page.
NOAA Operational Data!
This link should
be put into another more relevant note one day. I can download from
this link at approximately 2 Gigbytes/hour!
WMO Documents and
Reports
Links to a bunch of WMO reports.