[NARCCAP-discuss] Questions on data for our project.

[ping yang]

Dear Seth,

Thank you so much for the previous advice on data and operations with
NARCCAP data.

Actually I have question on both the data downloading and data analysis(I
will be appreciated if you can cover tomorrow)
1)I have a user ID and I tried to download the NARCAAP data but without
success
2)I have difficulty in running some scripts that you mentioned for temporal
aggregation because lack of knowledge in NCL, it will be nice if you can
provide some information tomorrow

Looking forward to meeting you tomorrow.

Regards,

Ping

On Mon, Mar 12, 2012 at 11:17 PM, Seth McGinnis <mcginnis at ucar.edu> wrote:

> Hi Ping,
>
> All the NARCCAP data is 3-hourly, so if you want daily and monthly
> averages,
> you'll have to do the averaging yourself.  The only exceptions are the four
> variables in Table 1, which are inherently daily values.  (We do have
> plans to
> make a number of monthly and seasonal averages and climatologies
> available, but
> they're not ready yet.)
>
> If you're an NCL user, I wrote a script ("aggregate.ncl") for creating
> various
> time-averages that you may find useful.  You can find it here:
> http://narccap.ucar.edu/contrib/tools/ncl/  It's also pretty easy to
> create
> those time-averages using the NCO command "ncrcat" and the multislab
> feature.
>  (Especially if you have NCO installed with udunits support, and can use
> date
> ranges for subsetting the time coordinate -- see my post to the
> narccap-discuss
> mailing list of about a week ago for more details.)
>
> To get the variables that you list, you'll need either to change units or
> calculate them from other variables, depending. The published data
> includes:
>
> * tas = surface air temperature in degK
> * pr = precipitation in flux units (kg/m^2/s)
> * ps = surface air pressure (in Pa)
> * clt = cloud cover (fraction from 0 to 1 -- look in Table 3 for this one)
>
> I wrote a couple shellscripts that use NCO commands to change units for
> temperature and precipitation.  You can find them here:
> http://narccap.ucar.edu/contrib/tools/util/  The "tas2temp" script
> converts
> degK to degC, and "pr2prec" converts precip from kg/m^2/s to mm/day.  The
> commands to convert ps files from Pa to mbar would be entirely analogous.
>
> Relative humidity can be calculated from specific humidity, temperature,
> and
> pressure (variables huss, tas, and ps).  There's an NCL script
> ("calc_humid.ncl", which also calculates dewpoint) in that
> contrib/tools/ncl
> directory on the website.
>
> I haven't had cause to calculate wet bulb temperatures yet, so I can't
> offer
> any tools to help with that yet, sorry.
>
> Cheers,
>
> --Seth
>
>
> On Sun, 11 Mar 2012 11:19:00 -0600
>  ping yang <pingyang.whu at gmail.com> wrote:
> >Dear NARCCAP users,
> >
> >I need data for the following items with daily step and monthly step:
> >
> >•Precipitation –Units (mm)
> >
> >•Surface Air temperature –Units (°C)
> >
> >•Surface Air pressure –Units (mbars)
> >
> >•Humidity (relative )
> >
> >•Wet bulb temperature –Units (°C)
> >
> >•Cloud Cover
> >
> >I looked into the NARCCAP data tables, actually there are so much
> >information that I am a little confusing,  e.g., I found the Max/Min
> >Surface air temperature data in daily but the instantaneous surface
> >air temperature data in 3 hours, and some data like Wet bulb
> >temperature I don't know how it was classified or named in the NARCCAP
> >dataset.  Is here someone has the same experiences who can give me
> >some instructiona on how to get those data or some suggestion on how
> >to process the available data?
> >
> >All the Best,
> >
> >Ping
> >--
> >Ping Yang, Ph.D.
> >Postdoctoral Research Associate
> >CUNY Environmental Crossroads Initiative
> >_______________________________________________
> >narccap-discuss mailing list
> >narccap-discuss at mailman.ucar.edu
> >http://mailman.ucar.edu/mailman/listinfo/narccap-discuss
>
> _______________________________________________
> narccap-discuss mailing list
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>



-- 
Ping Yang, Ph.D.
CUNY Environmental Crossroads Initiative
Marshak Science Building - Suite 925
The City College of New York - CUNY
160 Convent Avenue, New York NY 10031
Phone: 212-650-5769
Fax: 212-650-7064