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Collecting and analysing Argo Float data

Using Google Earth you can follow the path of any Argo Float, anlayse the data that it uploads, and learn about what is happening in the oceans.

Searching for Argo Floats

You can see every Argo Float on ‘Google Earth’ and follow the path of any selected Argo Float. 

Argo Floats around New Zealand

Above: here are all the Argo Floats around the coast of New Zealand. Can you spot Argo Float #5903777? It is in the Pacific Ocean to the east of Palmerston North.

Argo Float trajectory

Above: by clicking on the dot beside Argo Float #590377 you can see its trajectory (path) since it was deployed. The location of its launch is marked as a yellow box. 

Argo Float trajectory with all the uploaded profiles

Above: you can choose to see all the locations where Argo Float #590377 surfaced and uploaded a profile to a satellite. How many profiles have been uploaded so far? Has the Argo Float drifted north or south since it was released. What direction is it drifting now?

Argo Float profile

Above: by clicking on one dot you can see the profile that was uploaded at that location. This profile was from cycle #141, uploaded on the 16th March 2014 at latitude 37.926S and longitude 179.962E.

Below: by clicking on the small graphs you can see one temperature and salinity profile for that location in more detail.

What is happening here? Salinity falls rapidly from 35.5 to 34.4 but then stays at 3.4. before rising to 34.6.
An Argo Float salinity profile (showing changing salinity with depth)		 What is happening here? Temperature falls rapidly from 19 degrees at the surface to 4 degrees and then more slowly to 2.5 degrees at the deepestAn Argo Flat profile showing changing temperature with depth

Analysing Argo Float data

One temperature or salinity profile is not as useful as many profiles combined together. The website at the Woods Hole Oceanographic InstitutionExternal link has combined the data for all Argo Floats. The following two graphs are similar to the ones above but combine all the data for Argo Float #5903777 (off the east coast of the North Island).

Interpreting the Argo Float profiles means thinking about:

  1. the float trajectory
  2. the climate of the region the float has passed through
  3. the currents that have moved the float from place to place.

All salinity profiles combined for Argo Float #5903777

Things to look out for in the salinity (S) profiles:

  • How does the surface salinity compare with the salinity at 2000m depth? Can you explain this difference? 
  • Looking at all the profiles together, what is the salinity range near the surface? How does this range compare with the range at 2000m depth?
  • Is there any part of the plot where the differences between earlier and later profiles is particularly great?

 

Note that the earliest profiles are blue; the latest are deep red and brown. 

 

 

Combined temperature profiles for Argo Float # 5903777

Things to look out for in the temperature (T) profiles:

  • How does the surface temperature compare with the temperature at 2000m depth? Can you explain this difference?
  • Is there a 'thermocline' - a depth interval where temperature changes markedly with depth?
  • Looking at all the profiles together, what is the temperature range near the surface? How does this range compare with the range at 2000m depth?
  • Is there any part of the plot where the differences between earlier and later profiles is particularly great? 

Note that the earliest profiles are blue; the latest are deep red and brown. 

Salinity contour for Argo Float #5903777This diagram combines all the salinity data across all 147 profiles that Argo Float #5903777 has uploaded.

 

What is happening here?
The saltier water is nearer the surface. Water at deeper levels has less salt.

 

Temperature contour for Argo Float #5903777This diagram combines all the temperature data across all 147 profiles that Argo Float #5903777 has uploaded.

 

What is happening here?
The water near the surface is warmer.

Water at deeper levels is coldest. 

Note there was warmer surface water in profiles 60-75, 100-110 and 130-140. Why do you think might be?

 

 

 

 

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A profile showing changing temperature with depth underwater. You can see that the water in the top layer (1,000m) cools quickly with depth. Below that the temperature changes very slowly with depth. The top layer is called a thermocline. Image source

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1 Here are all the Argo Floats around the coast of New Zealand. Can you spot Argo Float #5903777? It is in the Pacific Ocean to the east of Palmerston North.

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2 By clicking on the dot beside Argo Float #590377 you can see its trajectory (path) since it was deployed. The location of its launch is marked as a yellow box. 

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3 You can choose to see all the locations where Argo Float #590377 surfaced and uploaded a profile to a satellite. How many profiles have been uploaded so far? Has the Argo Float drifted north or south since it was released. What direction is it drifitng now?

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4 By clicking on one dot you can see the profile that was uploaded at that site. This profile was from cycle #141, uploaded on the 16th March 2014 at latitude 37.926S and longitude 179.962E.

Next step learning: Use Google Earth to adopt an Argo Float deployed during this June 2014 LEARNZ field trip. Details of the Argo Float (eg its WMO number and location) will be available in the field trip diaries.

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