Climate News Study
• A member of the general public has found a copy of
the (attached) graphic on the New York Times
website. They see the tag line as NSIDC and want to
find the data that was used to make the chart.
This person also found the (attached) scatterometry
image attributed to Dr. David Long at BYU and wants
to intercompare these two data sources. Before
doing that they must locate the original data used to
produce the graphics.
Climate News Study
Instructions
1. Define the steps needed to fulfill the scenario
1. Steps needed for access to the data
2. Data types or data sets needed
2. Suggest a strategy that fulfills the steps
3. Which of these steps in your strategy are available
through NSIDC, JPL (or internet) resources?
4. What specific observations do you have about the
NSIDC or JPL data system while working this
scenario?
5. Comment on the efficacy of web sties or specific
web pages --- use screen capture of web pages to
show specifics
Step 1
1. Define the steps needed to fulfill the scenario
1. Steps needed for access to the data
2. Data types or data sets needed
•
Observations:
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Before doing 1.1 above, I would do 1.2. Carefully reading
the scenario indicates that my task is: Find the data used
to make the NSIDC chart and the data used to make the
David Long scatterometer image, thus enabling an
intercomparison of the two datasets
Therefore, I need:
•
•
NSIDC Arctic Sea Ice Extent time series for 2007, 2008, and
the 1979-2000 mean
David Long (BYU) scatterometer data covering the Arctic
Step 2
2. Suggest a strategy that fulfills the steps
•
Observations
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The first thing I would do to find the source data for the NSIDC Artic
Sea Ice Extent data would be to do a Google search, even though I
already know it comes from NSIDC.
I search for “NSIDC Artic Sea Ice Extent” and click on the first return,
Cryospheric Climate Indicators: Sea Ice Index
This takes me to http://nsidc.org/data/seaice_index/, which looks like
the right place to be to find the data
Perusing the page, I quickly find “archived data and images” link on the
left, then click it.
I want data not images, so I click on “Get Extent and Concentration
Data”
There is a README.txt file on the FTP site I am taken to. I read it and
am annoyed when it tells me to go to another page,
http://nsidc.org/data/g02135.html. Of course, I can’t click on on the link
(this is an FTP plain text file) so I have to copy and paste URL to my
browser window.
Step 2
2. Suggest a strategy that fulfills the steps
•
Observations (continued)
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So, I create a new tab and paste that URL into. Still annoyed…
especially when the link “Product Web Site” takes me back where I
started. I don’t want to be there, so I hit the back button.
The metadata link is nice to see, so I read that. I still don’t see a
format description, so I go to my other tab with the FTP site open.
I click on “Apr”, then on “N_04_area.txt” and discover that the format is
so simple it did not need a separate description. I think the
README.txt file was misleading… it should have told me more
specifically what each of the “Jan”, “Feb”, etc. directories contained,
and that images and data are there and self-documented.
Then I am annoyed again because I have to do all this clicking for all
12 months, or at least the 5 months in the chart. The climatology is not
pre-generated, so I have to compute that myself (it is easy to do, but
why not provide that as well?)
I am not a heavy GIS user, but do occasionally read shapefiles into
Matlab so I am glad to see those are available as well.
Step 2
2. Suggest a strategy that fulfills the steps
•
Observations (continued)
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At this point I have the source data for the NSIDC chart. Now I
turn my attention to the David Long (BYU) data.
Again, I turn to Google and do a search on “David Long BYU
Scatterometer”
First two hits are on his student list and some other members
list, so I follow the third link which takes me back to NSIDC to
http://nsidc.org/cgi-bin/get_metadata.pl?id=nsidc-0261
I review the metadata record that is returned… I am familiar with
metadata so am not frightened away, but many users might be
at this point
I find the online resource element, but then focus on “VIEW
PROJECT HOME PAGE” which takes me to BYU web site
Step 2
2. Suggest a strategy that fulfills the steps
•
Observations (continued)
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I am now at http://www.scp.byu.edu/derived.html
I read this and see “Sea Ice Extent Products”, which mentions
QuikSCAT and NSCAT and looks like the most likely place.
Fortunately I know these are scatterometers, so I click on it.
I now have a page that talks about “Eggs” and “Slices” for the Arctic
and Antarctic. I have no idea what there are, but clicking on either
returns a huge HTML table listing a million and one images.
Fortunately I see the small link for “AVE or grd” so I follow that, then
drilling down, down, down to
ftp://ftp.scp.byu.edu/data/qscat/2006/aux/qaeh/Arc/002/C/
before I ever see a file I might be able to download… but I don’t
bother at this point because I have no idea what all these
subdirectories are.
Step 3 and Step 4
3. Which of these steps in your strategy are available
through NSIDC, JPL (or internet) resources?
•
Observations
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I was able to easily find the NSIDC data at NSIDC in a form I could
use. Unfortunately, even though they had metadata about the David
Long data, I still seemed to have to go to his web and FTP sites.
Those sites assumed a high level of familiarity with the scatterometer
data, which I do not have.
4. What specific observations do you have about the NSIDC
or JPL data system while working this scenario?
•
Observations
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The NSIDC system seemed fairly clean and intuitive. In my comments
I mentioned a minor or improvement or two, but the overall impression
is positive and certainly more usable than David Long’s interface
(though, once armed with some basics his site might be fairly usable
too).
Step 5
5. Comment on the efficacy of web sties or specific
web pages --- use screen capture of web pages
to show specifics
•
Observations
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I’ve made several observations as I’ve gone through the
process, but a more general look at the NSIDC gives a positive
impression - I like that there are relatively few links, and quick
links to the data.