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Marine Data Literacy 2.0

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Home > 4. Ocean Data View > 4.14 Coriolis NetCDF

4.14 Obtaining NetCDF Operational Marine Data (Argo Profilers/GTSPP/SOOP) from Coriolis

  • Exercise Title:  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):

  • Required Software:

  • Other Resources: 

  • Author:  Murray Brown

  • Version:  8-1-13
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 much?

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 present.
5.  Take some time to read through the Coriolis nest of webpages.  Then open Coriolis Operational Oceanography Data Selection
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 today.

NOTE:  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 items.]
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 one.

Your data file is available at
 ftp://ftp.ifremer.fr/ifremer/coriolis/tmp/co0501/DataSelection_20130801_164932_84862.tgz
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 ).
Best regards,
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 :
 
18.  Right-click 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:
  • argo-profiles-xxxxx.nc
  • 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 cruises
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.