14 replies to this topic

[lorenzo]

With the models under some degree of scrutiny I always forget which has higher resolution here and there and at what time frames. After some digging around put this together and hope it is some use as a point of reference, this is not my area of expertise so please edit, add to, correct, grow etc etc

Data for numerical weather prediction is provided by observations from satellites, from the ground (both human and from automatic weather stations), from buoys at sea, radar, radiosonde weather baloons,, wind profilers, commercial aircraft and a background field from previous model runs. The gist of this is shown by this handy pic from a non-blacked out Wikipedia and ensembles depicted from UKMO website.




UKMO Unified Model - Global Model
25Km Resolution 70 Vertical Levels 144 Hours

UKMO North Atlantic and European Model NAE
12Km Resolution 70 Vertical Levels 48 Hours
UKMO - Other
1.5km Resolution UK 70 Vertical Levels 36 Hours
4Km Resolution Surrounding Areas
　

　
ECM / IFS
16 /31km? unsure..
Operational / Deterministic run is Twice Hortizontal Resolution of Ensembles 240 Hours
Operational 60 Vertical Levels
Ensembles 40 Vertical Levels
51 member Ensemble suite http://www.ecmwf.int...techniques.html
　

GFS
35 km / 64 vertical layers High Resolution runs to 192 Hours / 7 days - every 3 hrs
70 km / 64 vertical layers Lower Resolution runs from 192 - 384 Hrs - every 12th hr
22 Ensemble Suite 9 including Control / Operational

GEFS
using current operational GFS
-increase in horizontal resolution from 70 km to 55 km (T254) for 0-192 h, and 70 km (T190) for 192-394 hours
-increase in vertical resolution from 28 to 42 layers for 0-384 hours

http://www.emc.ncep..../GEFS/mconf.php

Edited by lorenzo, 24 January 2012 - 21:04 .

[Isolated Frost]

I am sure the ECM deterministic run is shown at a 16km resolution- and it's control at 31km, at least according to the EPS grams they give ?

[danm]

Thanks for that.

The GFS high resolution is 35km/64 vertical layers according to what you've posted - perhaps this shows why the GFS's verification stats are usually lower than the ECM & UKMO as their high resolution operational's are 16km and 25km respectively?

Edited by danm, 25 January 2012 - 00:30 .

[bluearmy]

the GEFS info is for the new parallel rather than the existing normal output.

on the parallel gefs, i think the control runs at 55km res all the way through.

[Liam J]

Afternoon all, just to add - the GFS model was upgraded from 35km to 27km resolution last year and runs at this resolution up to 192hrs. The rest of the run is produced at 70km resolution.

http://www.ncep.noaa...em_announce.pdf


Global Forecast System (GFS) Upgrade Implemented July 28, 2010

An extensive set of improvements to NCEP’s Global Forecast System will be implemented
into NCEP operations on Wednesday, July 28, 2010, following three years of development,
evaluation and testing. One of the major changes is an increase in the model’s horizontal resolution
from approximately 35 km to 27 km. Additionally, a number of improvements have been made to
the model’s ability to represent physical atmospheric processes. These improvements include an
upgraded radiation and cloud package, upgraded specification of gravity wave drag, a higher
resolution grid for hurricane relocation, an upgraded boundary layer scheme, the use of a higher
resolution snow analysis, a new mass flux shallow convection scheme and an updated deep
convection scheme. Also, the model will have a horizontal resolution of 27 km through 192 hours
in support of the GFS MOS development, which is an additional 12 hours from the previous
version. The model’s resolution from 192 to 384 hours will remain at 70 km. Finally, the
availability of three hourly forecast output will be extended out to 192 hours from 180 hours.
The result of this set of changes is improvement in the overall accuracy of the model’s
forecasts. In addition, a significant improvement in precipitation verification scores resulted
from a reduction in the appearance of spurious excessive amounts of precipitations occurring
over small geographic areas. An example of the elimination of these so-called “bulls-eyes” is
illustrated in the maps below.

Edited by Liam J, 25 January 2012 - 14:01 .

[bluearmy]

re ecm ens:

to day 10 at a resolution of 50 km

days 11 to 15 at a resolution of 80km

running at 62 levels

[Seselwa]

Regarding the ECM operational - How many days are run at 16km resolution?

[bluearmy]

Higrade, on 27 January 2012 - 00:12 , said:

Regarding the ECM operational - How many days are run at 16km resolution?

the op only goes to day 10. all at 16km resolution (thats why each frame takes so long to come out)

[bluearmy]

now that the gefs parallel has gone live, it should be noted that post day 10, the gefs are running at a higher resolution than the ecm ens. also, the gefs control post T192 should be given as much weighting as the gfs op as it is running at a slightly higher resolution (though at fewer vertical layers).

the general point is that, theoretically, the GEFS post day 10 with their trending should now be seen as comparable to the ecm ens.

Edited by bluearmy, 16 February 2012 - 21:46 .

[lorenzo]

TY blue, I think the other night when I was steaming i was tryingto get my head round this

[summer blizzard]

Anybody know where the GEM model stands in resolution, it seems to be on a par with at least the GFS in my opinion.

[weathermaster]

summer blizzard, on 11 March 2012 - 01:40 , said:

Anybody know where the GEM model stands in resolution, it seems to be on a par with at least the GFS in my opinion.

I believe it does 15km up to 48 hours then after that switches to 35km up to day 10. So the same as GFS but GEM's short range is run in a higher res and it does 10 days of 35km res meanwhile the GFS only does 7 days of 35km res.

Edited by weathermaster, 11 March 2012 - 02:52 .

[bluearmy]

weathermaster, on 11 March 2012 - 02:51 , said:

I believe it does 15km up to 48 hours then after that switches to 35km up to day 10. So the same as GFS but GEM's short range is run in a higher res and it does 10 days of 35km res meanwhile the GFS only does 7 days of 35km res.

gfs op is 27km out to T192

thanks for posting re gem horizontal resolution. do you have info re the number of layers it operates on ??

[weathermaster]

bluearmy, on 14 March 2012 - 18:15 , said:

gfs op is 27km out to T192

thanks for posting re gem horizontal resolution. do you have info re the number of layers it operates on ??

Its hard to find any information on the GEM model but after looking around I came across something saying it uses 27 vertical sigma layers. I'm not sure what that means maybe GEM works differently to the others? I have a few PDF links about the GEM model if anyone wants to read through them I can post them here if you want.

Edited by weathermaster, 14 March 2012 - 19:03 .

[johnholmes]

sigma layers are those that, especially close to the ground are in close conformity to the actual terrain beneath the spot location