Prajeesh,
Admittedly, it is a simple scheme to identify whether the rainfall
is snow or water based on T850.
However, this is not a conversion; it is just an identification. Latent
heat is considered in the microphysics.
More advanced microphysics will provide rain and snow rates directly.
I hope this helps.
Regards,
Moorthi
On 10/20/2014 05:45 AM, Prajeesh A.G. wrote:
>
> I have a doubt regarding the snow-rain conversion in CFS.
> In the model, the total precipitation is considered as snow fall if
> the temperature at 850hpa is below 0C.
>
> See the below code from gbphys_v.f
> ! --- ... lu: snow-rain detection is performed in land/sice module
> ! factor=weighted mean tep.
>
> do i = 1, im
> tprcp(i) = rain(i) ! clu: rain -> tprcp
> srflag(i) = 0.0 ! clu: default srflag as 'rain'
> if ( t850(i) <= 273.16 ) then
> srflag(i) = 1.0 ! clu: set srflag to 'snow'
>
> ...................
>
> do i = 1, im
> ! if ( t850(i)<=273.16 .and. slmsk(i)/=0.0 ) then
> if ( t850(i) <= 273.16 ) then
> lprec_cc(i) = 0.0
> snw_cc(i) = rain(i)
> else
> lprec_cc(i) = rain(i)
> snw_cc(i) = 0.0
> endif
> enddo
>
> Here the 'srflag' is used in the sfc_drv (Land model) to detect
> whether the falling precipitation is snow or not. Similarly snw_cc
> goes to ocean model.
>
> My doubt is, where is the latent heat of fusion released during this
> conversion?
>
> *Regards..*
>
> Prajeesh A G
>
--
Dr. Shrinivas Moorthi
Research Meteorologist
Global Climate and Weather Modeling Branch
Environmental Modeling Center / National Centers for Environmental Prediction
5830 University Research Court - (W/NP23), College Park MD 20740 USA
Tel:(301)683-3718
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