Obtaining NetCDF Operational
Marine Data (Argo Profilers/GTSPP/SOOP) from Coriolis
Abstract: In this
exercise you'll explore the Coriolis Data Service, operated by France,
which provides easy access to many operational oceanographic projects and
systems. We'll identify and download the Argo profiler data to
complete the collection we made from WOD profiler data. Then we'll
use the ncBrowse program to examine the downloaded data to determine its
scope and general content.
Preliminary Reading (in
OceanTeacher, unless otherwise indicated):
|1. This is the main station
map for the profilers data collection for Liberia from WOD (if you made
it). We know
that much data has been collected since the publication of WOD, but how
NOTE: Don't worry if you didn't make this collection.
Your bottle data collection should look similar.
|2. Navigate to
PRODUCTS > ODV >
pfl_2005_2011_liberia_wod.Data > misc and open the file Inventory.txt with
Excel (or any ASCII editor).
|3. Examination of the
inventory reveals that the TIME PERIOD goes up to January 1, 2010. So
WOD is actually being updated continuously, with at least
some of the operational data.
|4. So we need to
find a source of the profiler data (which actually came from the Argo program) since
January 1, 2010, and add these later data to our collection to bring it up
to date. To keep things
simple, in this exercise we'll only for the past year of data. In
practice, you might want to go for all data from January 1, 2010 to the
|5. Take some time
to read through the Coriolis nest of webpages. Then open
Coriolis Operational Oceanography
|6. This very detailed
and comprehensive graphical interface opens.
Coriolis is an amazing data service, providing oceanographers with the
latest data from numerous operational systems., as you can see from the data
types listed below the map.
|7. To begin the process,
enter the coordinates of the Liberia project area
extended at least 1 degree in each
direction, and the start and end dates for the year previous to
There is a ZOOM TO AREA tool. You'll need it below.
|8. In the VERTICAL PROFILES
area, select only these items, and uncheck the others. [On your own
time you can investigate these interesting items.]
|9. Uncheck all of these TIMES
SERIES items. [On your own time you can investigate these interesting
|10. Select PARAMETER
INCLUDING > ANY, and also QUALITY > GOOD DATA ONLY.
|11. Make sure you have
DOWNLOAD > NETCDF ARGO, and also MAP DISPLAY > PNG.
Then click on REFRESH
|12. After a short wait (be
patient!) the map is redrawn to show only the data of interest.
|13. Use the ZOOM TO AREA tool
to see the data more closely:
- Stations in curving lines are probably Argo floats, which
appear at the surface periodically to report subsurface data
- Stations in many long straight lines are from ships of opportunity
(SOOP) cruises. At least 5 such lines are in this map
- Stations in straight lines that run north-south, east-west,
onshore-offshore or in a grid pattern are probably from research or
survey oceanography cruises. At least 3 such patterns are
present in this map.
|14. Click on DOWNLOAD.
|15.. This data request form
appears, which you should fill out. Make sure to say something in the
COMMENT field so the Coriolis folks know what you're studying.
Then click VALIDATE.
|16. This message indicates
everything is OK. You can close the message window.
|17. In a very few minutes you
will receive an acknowledgement email, and then after about 1 hour an email similar to this
Your data file is available at
In publications, please use the following citation statement:
These data were collected and made freely available by the Coriolis project
and programmes that contribute to it (http://www.coriolis.eu.org
Coriolis data management team.
Content of the compressed file :
[File-by-file descriptions of each data
location; omitted here for brevity]
Production time: 0:44:19(HH:MI:SS)
Your data selection parameters are :
- File format : NETCDF
- Coordinates (Lat - Lon) : -6 9 -23 -3
- Period (DD/MM/YYYY) : '01/08/2012' '01/08/2013'
- Data type(s) : ('Argo profiles','XBT profiles','CTD profiles')
- Required Physical parameters :
- Quality : GOOD
- Processing Level :
on the ftp link in the message and select SAVE AS. Then navigate to
the folder DATA > OCEAN and save the file as
argo_xbt_ctd_20120801_20130801_liberia_any_good_coriolis.tgz (or as
appropriate for the dates of your work).
|19. Use WinZip
(or any unzipping program compatible with the TGZ format) to unzip the TGZ
file you just saved file.
It produces a new folder with a name like
DataSelection_20130801_164932_84862 containing dozens of NetCDF files
(*.NC). Examine the contents, and you'll find:
- ctd-profiles-xxxxx.nc - probably from the research/survey
cruises; remotely possible from SOOP vessels with special XCTD probes
- xbt-profiles-xxxxx.nc - from either SOOP or research/survey
|20. Now you know
how to obtain archived data for any historical time period. You could,
for example, go ahead and obtain the data from the previous 2 years in the
same way. We're going ahead now with the process of importing the data
we have into Ocean Data View.