[RegCNET] to validate the model

BI XUNQIANG bixq at ictp.trieste.it
Fri Jul 21 09:00:16 CEST 2006


Hi, Zhang Yan:

How are you recently ?

On Tue, 18 Jul 2006, Yan Zhang wrote:

>        To validate the model performance, I want to use the ICBC data.  What 
> I used is NCEP NNRP2, but I found the ground temperature from RegCM3 could be 
> 3 to 4 degree lower than that from NNRP2. I wonder if it is reliable using 
> NNRP2 to evaluate the model, because i know the spacial resolution of NNRP2 
> is too coarse, like 2.5*2.5 degree?

You know, in ICBCyyyymmddhh, for ground temperature, the value over ocean
in the observed SST (from weekly or monthly), which is not related to
NNRP2. While over land, we use the vertical interpolation based on lapse 
rate (6.5 C/km).

In the ICTP June workshop, there is a discussion about the lapse rate
problem. Does anyone have a better vertical interpolation method ?

We plan to work on this issue, to find a more consistent solution
for the vertical interpolation.

Best regards,
Xunqiang Bi
>
>         I really appreciate your help.
>
>          Another question is if the newest version improved rainfall? I 
> tried Emmanuel convective scheme over south American,  but rainfall does not 
> show great improvement compared with observational data. Especially, the 
> monthly mean convective rainfall spacial distribution looks unrealistic, 
> although it looks very smooth comparing with simulation by using Grell 
> scheme.
>          I made a slight modification to the model, I got a really good 
> results of sensible flux (SH) and latent flux (LH) including monthly mean and 
> diurnal cycle, but such a big change of SH and LH doesn't influence rainfall 
> much. I am interested dry season (Jun~Oct) over Amazonia where the convective 
> rainfall dominant during the period. I expected LH would have a great 
> influence to rainfall. But I never get the expected results.  I wonder if the 
> rainfall scheme works out in the model.
>
>          I did not plan to write too much, but I know this is the only place 
> we can discuss RegCM3 together. I don't mean RegCM3 is not good enough.  I 
> pointed out the problem, in case other one struggling to the same problem. I 
> also wish if anyone would like to discuss it with me.
>
> Best
>
> Yan 
> _______________________________________________
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> RegCNET at lists.ictp.it
> https://lists.ictp.it/mailman/listinfo/regcnet
>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   Dr. Xunqiang Bi         email:bixq at ictp.it
   Earth System Physics Group
   The Abdus Salam ICTP
   Strada Costiera, 11
   P.O. BOX 586, 34100 Trieste, ITALY
   Tel: +39-040-2240302  Fax: +39-040-2240449
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



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