[NARCCAP-discuss] Interpreting NARCCAP Data

Thu Feb 23 11:50:58 MST 2012

Seth and Sinha:
	Some minor details to add to Seth's thorough responses:
(1) Table 1 variables are not all averages.  The sea-ice fraction is, but
the other 3 fields are the instantaneous min/max value for the 24-hour
period. Also, note the definition of "day":
The "day" for daily min/max values (Table 1) is from 06 UTC - 06 UTC, with
the date stamp referring to the beginning time.
(2 & 3) Strictly speaking, the NCEP-driven runs started in 1979, but we
usually ignore the first 2-3 years as a model spin-up period.
Similarly, you might note that the GCM-driven runs start in 1969 and 2039,
but again, we discard the first 3 years for spin up.

(5) It might be useful to check with the user community, because someone
somewhere may have calculated heating/cooling degree days, or put
temperatures into bins.

Thanks, Seth, for your detailed answers.

Bill

-- 
William J. Gutowski, Jr.

3021 Agronomy Hall
Dept. of Geological & Atmospheric Sciences
Dept. of Agronomy
Iowa State University
Ames, Iowa  50011-1010

Tel:  1-515-294-5632
Fax: 1-515-294-2619
http://www.ge-at.iastate.edu
http://rcmlab.agron.iastate.edu

On 2/23/12 12:38 PM, "Seth McGinnis" <mcginnis at ucar.edu> wrote:

>Hi Sinha,
>
>(1) The variables in Table 1 are daily average values.
>Everything else is at 3-hourly frequency.  We are working on
>developing aggregations of the data (monthly and seasonal
>averages and climatologies), but they're not ready for
>publication yet.  However, you can find the NCL script that we
>use for the bulk of the data manipulation here:
>http://www.narccap.ucar.edu/contrib/tools/ncl/aggregate.ncl
>
>(2) The NCEP-driven runs cover 1980-2004.  For the GCM-driven
>runs, there are two runs for each GCM-RCM pairing.  The current
>run covers 1971-2000 and the future run covers 2041-2070.  See
>http://www.narccap.ucar.edu/about/time-periods.html for more
>details.
>
>(3) See above.
>
>(4) The variables in Table 1 are daily averages.  Table 2 has
>the 2-D surface variables of interest to impacts modelers: temp,
>precip, pressure, incoming solar radiation, and u- and v-winds.
>Table 3 has all the rest of the 2-D variables.  Table 4 has
>static (i.e., not time-varying) variables like elevation.  Table
>5 is 3-D data.
>
>(5) All variables are available for the entirety of the
>simulation period.  There may be missing data in spots due to
>problems when data was saved or post-processed, but it's nothing
>systematic.  We have tabulated the timesteps where data is known
>to be missing here: http://www.narccap.ucar.edu/data/missing/
>
>Currently we have data available for temperature, precipitation,
>and snowfall.  You can calculate relative humidity from specific
>humidity, temperature, and pressure (all of which are available),
>and we're working on developing those datasets, but they're not
>yet ready for publication.  Here's the script we'll use:
>http://www.narccap.ucar.edu/contrib/tools/ncl/calc_humid.ncl
>We don't have heating and cooling degree days, though we may do
>them at some point.
>
>(6) No.  We have nothing available in temperature bins.
>
>
>Extensive documentation of the data structure, organization, and
>availability can be found on the website: http://narccap.ucar.edu/
>See particularly the "About Data" and "About NARCCAP" sections.
>
>Cheers,
>
>--Seth
>
>
>
>On Wed, 22 Feb 2012 11:47:19 -0500
> "Sinha, Paramita" <psinha at rti.org> wrote:
>>Hi,
>>
>>I am exploring the idea of using the NARCCAP RCM data to  project
>>migration patterns of US households under climate scenarios. I am
>>interested in using output from different GCM/RCM so that I can study
>>sensitivity.  I need to know how to interpret the variable names
>>correctly, so that I use the appropriate datasets. Some preliminary
>>questions I have are as follows:
>>
>>(1)    What is the temporal structure (e.g. Is the data available at the
>>daily/monthly levels?)
>>
>>(2)    What time periods can we get projection data for (e.g. yearly
>>till 2100??)
>>
>>(3)    What do the terms current and future exactly mean? (e.g. the
>>HRM3-HadCM3 has two sets of tables)
>>
>>(4)    What is do these each of the tables represent?? (e.g. Table 2:
>>Primary 3-hourly surface fields (2-D))
>>
>>(5)    Are data on temperature, precipitation, heating degree days,
>>cooling degree days, snowfall, relative humidity  projections available
>>for each month of the year? Which tables are relevant?
>>
>>(6)    Are data available in "temperature bins" ( e.g. number of days in
>>each 5 degree  temperature bins)? Which tables are relevant?
>>
>>Is there any detailed documentation/ references that I can look that to
>>get a better understanding of the data? I appreciate any help you can
>>give me!
>>
>>Thank you,
>>
>>Sincerely,
>>
>>Paramita
>>
>> 
>>
>>Paramita Sinha, PhD
>>
>>Senior Economist
>>Environmental, Technology, and Energy Economics
>>Research Triangle Institute
>>701 13th Street, NW, Suite 750
>>
>>Washington, DC 20005-3967
>>
>>Phone:  (202)9747875
>>
>>Fax: (202)9747855
>>Email: psinha at rti.org <mailto:psinha at rti.org>
>>
>> 
>>
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>
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