Plotting sleet and snow

Questions and other topics related to UEMS 18.
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weatherc
Posts: 67
Joined: Tue Sep 25, 2012 2:39 am

Plotting sleet and snow

Post by weatherc » Mon Sep 14, 2020 7:22 pm

Hi guys,
Long time no see :)

I'm looking for a snippet for plotting sleet and snow with Grads.
Found the old snippet
'define snowrainratio=(SNMRhy1+0.0000001)/(RWMRhy1+0.0000001)+0.01'
'define precthreshold=((SNMRhy1+RWMRhy1)*1000000)-1'
but can't found those variables in recent emsupp.parm-file.

So do someone have any good snippet for detecting those? ;)

Cheers
Henkka

emsiwx
Posts: 87
Joined: Sun Aug 12, 2012 11:07 am

Re: Plotting sleet and snow

Post by emsiwx » Wed Sep 16, 2020 7:24 am

Hi,

add the following lines to your param control file:

# from: data/tables/post/grib2/emsupp_cntrl.HYBRID_ALL
(RWMR_ON_HYBRID_LVL) SCAL=(-4.0) ! Rain Water on Hybrid (Native Model) Surfaces (kg Kg-1) FNUM=(181)
L=(10000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000)
(SNMR_ON_HYBRID_LVL) SCAL=(-4.0) ! Snow Mixing Ratio on Hybrid (Native Model) Surfaces (kg kg-1) FNUM=(182)
L=(10000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000)
(GRLE_ON_HYBRID_LVL) SCAL=(-4.0) ! Graupel Mixing Ratio on Hybrid (Native Model) Surfaces (kg kg-1) FNUM=(415)
L=(10000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000)
(HAILMR_ON_HYBRID_LVL) SCAL=(-4.0) ! Hail Mixing Ratio on Hybrid (Native Model) Surfaces (kg kg-1) FNUM=(1056)
L=(10000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000

Regards,

EmsiWX

weatherc
Posts: 67
Joined: Tue Sep 25, 2012 2:39 am

Re: Plotting sleet and snow

Post by weatherc » Wed Sep 16, 2020 4:47 pm

Great, thanks!

Then just a question:
If use this code are 0 = "pure rain" and >=10 snow?

define snowrainratio=(SNMRhy1+0.0000001)/(RWMRhy1+0.0000001)+0.01'
'define precthreshold=((SNMRhy1+RWMRhy1)*1000000)-1'
'set clevs 0 0.1 10'
'd maskout(snowrainratio,precthreshold)'

emsiwx
Posts: 87
Joined: Sun Aug 12, 2012 11:07 am

Re: Plotting sleet and snow

Post by emsiwx » Tue Sep 22, 2020 11:52 am

Yes,from the formula (not by me) the lower the number snwmix compared to rainmix, the lower the result is and the greater chance for rain...small numbers added are to avoid division by zero, I guess...

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