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Float no.6900742

    Temperature and salinity profiles   Time series plots
  Download the data   Using the float data with ocean analysis maps    



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This APEX float was launched by Dutch scientists in the tropical Atlantic at 7.6°N, 25.5°W on 24 September 2009. It has recorded a total of 161 profiles, and made its last report on 4 March 2014 from 7.3°N,  22.4°W.

Float track

Launch of float 6900742, which belongs to the KNMI (Royal Dutch Meteorology Institute).

Float track

HMS Beagle at Tierra del Fuego

Float track

The Dutch clipper Stad Amsterdam

The float was launched from the Dutch clipper Stad Amsterdam while following the route of Darwin's voyage on HMS Beagle in 1831-1835, and is called 'FitzRoy' after the Commander of the original Beagle.

During the voyage of the Beagle, Darwin spent much of his time on land investigating geology and making natural history collections. He kept careful notes of his observations and thoughts, which were later published in his journal from the voyage. In Patagonia he rode with gauchos into the interior to explore geology and collect fossils. He found huge extinct mammals right beside fossils of modern seashells. High in the Andes he saw seashells and fossil trees that had grown on a sandy beach. On the Galapagos Islands he found birds related to those in Chile but differing from island to island. He also heard that slight variations in the shape of tortoise shells showed which island they came from. Years later these observations provided evidence for his theory on natural selection, published in 1859 in his book On the Origin of Species.

The 19th century voyage of the original Beagle lasted almost five years. The modern Beagle project followed Darwin's route in only one year from September 2009 to June 2010. See Beagle: In Darwin's wake for more about the expedition.

Temperature and salinity profiles

Temperature profiles Salinity profiles

Profiles of temperature (left) and salinity (right) from Argo float 6900742. The profiles show how temperature (T) and salinity (S) change with depth from the surface to 2000m. Early profiles are dark blue, the latest profiles are deep red or brown. Click on the images for larger plots.     Source of plots: IFREMER/Coriolis.

Time series of temperature and salinity

Temperature section Salinity section

Time series of temperature (left) and salinity (right) from Argo float 6900742. The sections show all the temperature (T) and salinity (S) profiles measured by the float during its life-time side by side. Each profile is represented by a very thin column where deep red is the highest values and deep blue the lowest. The colour bars on the right relate the colours to actual data values. Profile numbers are given along the top of the plot, with corresponding measurement dates along the bottom. Click on the images for larger plots.     Source of plots: IFREMER/Coriolis.

Using the float trajectories with ocean analysis maps

Look at the float trajectory in Google Earth to see where the float has been. (If in doubt about how to reveal the float tracks, see our Google Earth screenshot for help.) Compare this to the maps of temperature and salinity for different depths available for example from Mercator ocean analyses.

Downloading the float data

The Argo Information Centre has more information about this float. You can also download the data from one of the Data Centres - just select Data > Data Downloads.

There are many different formats available. ASCII data can be viewed in spreadsheets such as Excel. The other data types may require more specialist software.


Link to the main Euro-Argo project website.