Deployment of surface drifters and profiling floats from the
Semester At Sea's MV Explorer

Gustavo (center, first row) with the students, faculty and staff of the MV Explorer
on the Spring 2005 voyage during the April 7, 5:00PM, deployments

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As part of an agreement between NOAA/AOML and Semester At Sea, the MV Explorer became part of the voluntary observing system. Six surface drifters and six profiling floats were deployed from the Semester At Sea's MV Explorer during its April 2005 transect between Cape Town and Salvador (Bahia, Brazil).   Information about the initial contact and agreement between NOAA/AOML and Semester At Sea can be found in AOML's Keynotes

During this transect Cape Town- Salvador,  I (Gustavo Goni) had the pleasure of meeting a group of extremely motivated and scientifically curious college students and professors, who learnt about oceanography, the ocean observing  system, and who also helped me deploy the drifters and floats. Most of the 700 students and faculty members of the MV Explorer attended a 1.5 hour class on oceanography that I gave during the second day of the voyage.  This class was focussed on general ocean global circulation, on NOAA's observing platforms, and on NASA's satellite altimetry applications. Some of the material for this class was provided to me by several colleagues, particularly from NASA/JPL and NOAA/AOML.  Also, everyone helping with the deployments unknowingly attended a half an hour class to learn more about  these instruments.

The MV Explorer in  Cape Town, March 2005


The Instruments:

We deployed six surface drifters and six profiling floats.  Surface drifters are used to investigate surface currents in the world's oceans.  Profiling floats provide profiles of temperature and salinity from the surface to 1000-2000 meters deep.  All drifters and floats deployed from the MV Explorer are currently transmitting data, except for the float marked with an asterisk, which is currently not transmitting data.

Deployment sites:

The six deployment sites are shown in the map and table below.


Local Time



Drifter #

Drifter WMO #

Float #

Float WMO #

April 5

6:00 PM

07o 55W

24o 45S





April 6

5:00 PM

14o 58W

22o 09S





April 7

7:00 AM

19o 25W

20o 29S





April 7

5:00 PM

22o 43W

19o 14S





April 8

0:30 AM

25o 41W

18o 08S





April 8

7:00 AM

28o 55W

16o 53S





If you were in the MV Explorer during the transect and helped with the deployements, you probably wrote down the drifter and float #'s that were written in the cardboard boxes (highlighted in blue in the table above).  However, to follow these instruments you need to use their associated WMO ID numbers (highlighted in orange in the table above).


Tracking the instruments:

There are several NOAA's web pages you can use to follow the trajectories of these instruments and to retrieve the information that they are receiving.  If you are interested in looking up on a map where these instruments currently are, please follow the instructions below:

1) Profiling Floats: Go to this link and enter the WMO number of the profiling float in the box that is on the left of the page.   You will obtain a map with the trajectory of the float.   These trajectories are created using the location where the floats emerge to the surface after staying 10 days submerged at approximately 1500m deep.

2) Surface Drifters:
OPTION A.  Go to this link and do the following: a) select with you mouse in the little world map (bottom left) a region in the South Atlantic. b) click in the box that reads "platform", c) click on the box that reads "WMO code", d) click on the box that reads "currents" located in the bottom right, e) click on the box that reads "GO!"  This one requires plenty of clicking but it will also get very nice maps.   You will obtain a map that has surface currents derived from satellite altimetry.  The trajectory of the drifters during the previous 15 days are superimposed.  The little numbers that appear next to the trajectories are the drifter ID numbers.   If you want to see longer drifter trajectories, you need to change the number of days in the box located above the map (set to 15 days by default). 
OPTION B. Go to this link and do the following: a) select "GTS buoys" from the dropbox located above the map on the left, b) select a region (box) in the South Atlantic from the world map, c) Enter the drifter WMO/ID number, and d) click GO!.  This will allow you to follow a specific drifter.

If the above is a little too complicated, if there is a broken link, or you did not understand, please send me an email at


The deployments:

These are selected pictures taken at each of the six deployments.   If you were in this voyage and you have a picture that you would like me to include in this web page, please email it to me at


Were you in the Spring 2005 Semester Voyage?

I will like to hear from you if you were one of the students, faculty or staff members that helped with the deployments and if you are following the drifters and floats you helped to deploy.


I want to thank the Institute for Shipboard Education, Semester At Sea, and their wonderful students, faculty and staff members, and crew of the MV Explorer, for their help during the deployment of the drifters and floats and for their enthusiastic interest in learning about the ocean observing system..

Last but not Least

Before ending this page I want to share with you the pictures that I had taken with two incredibly nice people that I met before and after the voyage:

Robben Island

The tour guide in Robben Island (Cape Town), holding a replica of the key to Mandela's prison.

A boy from the Favela Calabar (Salvador) with my (now his) Ajax (soccer team from Amsterdam) hat.

If you have questions about this project or web page, please email Gustavo Goni.