[NARCCAP-discuss] Snow Density

[Jonas Roberts]

Hey Seth,

I wanted to follow up about snow density. I've noticed that some
models (e.g.WRFG_ccsm) state that snd is "snow depth in water
equivalent" in metres (from ncdump -h) while others (e.g. CRCM_ccsm)
just say "snow surface thickness" without units or further
elaboration.

After plotting an area-averaged mean annual cycle of snd for my region
of interest (northeastern Canada) it looks like values across several
models are of similar magnitude (off by a factor of 2 at most)
irrespective of what ncdump -h says.

Do you have any more insight into whether snd is actually snow water
equivalent for all models?

Thanks again,
Jonas

On Thu, Mar 22, 2012 at 8:13 PM, Seth McGinnis <mcginnis at ucar.edu> wrote:
> Hi Jonas,
>
> My (limited) understanding is that, unless the model has an unusually
> sophisticated snow algorithm, the density of snow in a climate model is
> typically 0.1.  So you can convert snd (snow depth) to swe
> (snow-water-equivalent) by simply dividing by 10.
>
> I plan to check with the modelers at our PIs meeting in a couple weeks to find
> out whether that's true for all the NARCCAP models.  If I find any exceptions,
> I'll post to the mailing list about it.
>
> As for the download problem, that sounds like a database error in ESG; I'll
> pass it on to the ESG team.  Thanks!
>
> Cheers,
>
> --Seth
>
>
> On Thu, 22 Mar 2012 09:56:55 -0230
>  Jonas Roberts <jonaspmr at gmail.com> wrote:
>>Hello,
>>
>>Is there a snow density value corresponding to the snow depth
>>variable? Is there an average value we should assume or some way of
>>determining the density from other variables? I'm trying to determine
>>the snow water equivalent in the snow pack.
>>
>>Also, when downloading snd data (individually) from the CRCM_ccsm data
>>set there were errors when downloading files like snd_CRCM_ccsm_
>>1991010103.v1.nc. However if I removed the .v1 from the URL then the
>>download started.
>>
>>Thanks in advance,
>>Jonas Roberts
>>PhD Candidate
>>Faculty of Engineering and Applied Science
>>Memorial University of Newfoundland
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>>narccap-discuss mailing list
>>narccap-discuss at mailman.ucar.edu
>>http://mailman.ucar.edu/mailman/listinfo/narccap-discuss
>
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