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Home > 9. Operational/Synoptic > 9.42 JPL/G1SST

9.42 Visualizing Operational Surface Temperatures "Blended" from Multiple Sources, in IDV: JPL/G1SST


  • Exercise Title:  Visualizing Operational Surface Temperatures "Blended" from Multiple Sources, in IDV: JPL/G1SST

  • Special Note:  Looking here for SST from satellites?  Right church, but the wrong pew.  This exercise covers the use of a product that blends data from multiple sources, including satellites. 

  • Abstract:  In this exercise, you'll probably make your first visit to the G1SST website, where is offered probably the most revolutionary SST product available today, a 1-km blend of satellite-measured, modeled and in situ measurements, 1 day or less old when published. Online subsetting is available now through IDV, so access to raster products is quick and easy.

  • Preliminary Reading (in OceanTeacher, unless otherwise indicated):

  • Required Software:

  • Other Resources: 

  • Author:  Murray Brown

  • Version:  09-30-2015

1.  As you have already probably read, the GHRSST exercises don't include the MUR and G1SST products, covered separately because they are huge files best handled through OPENDAP methods.

2.  Open the G1SST website and read about how these giant, high-resolution product files are created.  As you can see from the first page, below, you can control which of the data sources are included in the SST map product, the date (top left) and the area covered (bottom margin).  Take the time to look at your own areas of interest, and try to see which data sources are present for various dates, etc. etc.

3.  Here's how you can subset the data for a particular area, Liberia in this case.
4.  When you click PLOT, then this separate window appears with the new map.  There are no "download" controls for this map, so apparently you cannot obtain a data subset this way.
5.  There is a small control just at the bottom left that says PODAAC OPENDAP, which would seem to be the way to subset and download the data.
6.  We have tried this control for the current day and for many previous days, chosen randomly, and this is all we get.

So the "OPENDAP" server doesn't seem to work here.

7.  But we have an alternate way to get the data via OPENDAP.  To do this, run IDV.

8.  Then make these choices to get the data.   Just click ADD SOURCE (at the very bottom) to begin the process of mapping.

[Yes, there is also a MUR SST OPENDAP link, and you can explore this on your own.  It might be a good alternative to 9.34 Visualizing Satellite-Measured Surface Temperature Fields in IDV:  JPL/MUR, if the MUR data files found here are always the latest versions.]

9.  When the new map (named "1-day") appears, right-click on it and select PROPERTIES.
10.  On the PROPERTIES > PROPERTIES tab, change the name to something better, such as G1SST,
11.  Select the TIMES tab, and select USE SELECTED to pick only the latest day.

In this case, on September 28, the latest data day is September 27.

12.  Now click the SPATIAL SUBSET tab to begin getting data only for Liberia.
  • Draw a rectangle with your cursor anywhere near Liberia.
  • Then enter the latitude and longitude values for Liberia, as you see here.

Everything is set now, so you can click OK.

13.  Open the FIELDS > 2D GRID option, and select ANALYSED SST. 


The other options in the lower right corner have already been set by you in the above panels.

So click CREATE DISPLAY at the bottom.

14.  You should get a map something like this.  The map options (click on the ANALYSED SST link) have been set to RADAR > DBZ, the author's favorite palette.

15.  As you have seen in the final panels of  9.34 Visualizing Satellite-Measured Surface Temperature Fields in IDV:  JPL/MUR this grid can also be captured as a NetCDF subset in IDV, and later re-displayed as a raster image in Saga.