Monday, October 14, 2013

Mahmud Hasan Ghani's Internship, Fall 2013 - Part 3

Sail Buoy and Surface Salinity

Today I am going to write a short background of my data collection method and the new instrument used for this project. As I mentioned earlier in my first post, the SailBuoy is the new oceanic instrument which can be remotely operated and used for in situ data collection instead of surface buoys from a specific region.

It was March 2013,when the SailBuoy launched from south of Cape San Blas, from where it covered the 840 nautical mile (nm) area in her two months journey in the Gulf of Mexico. It was continuously transmitting data through its satellite communication in one-hour intervals. From the data pack, we retrieved the Sea Surface Temperature, Salinity and Oxygen of its passed ways. The application of the SailBuoy - an unmanned vessel - is just amazing. Just a single move with the SailBuoy in the Gulf of Mexico, and now we have data from approximately 840 nm area in a two month period. The basic difference between the fixed buoy and the SailBuoy, I think, is the coverage area. Fixed buoys are giving data continuously from one location, but the SailBuoy can cover large areas in a short time. Also, ocean going research vessels need a lot of scientific arrangement, manpower, and of course adequate investment to carry out the research; in some cases, the use of the SailBuoy would be the alternative to collect data in our concern area. Sudden accidental oil spills require immediate data collection from the spilled area to make further predictions, especially for oil drifting models in the region.

As we are focusing on how the Gulf of Mexico is more or less affected by oil spills, analyses of the physical properties of sea water, such as temperature, salinity, and oxygen are important for further research. In my last post, I discussed temperature variations for the study period and was able make some weekly sea surface temperature (SST) maps.

Involvement in a project like the SailBuoy data analysis is a great experience and learning period for me. From our real data pack, I have the conductivity data set but not the salinity data directly. Using some functions in MATLAB make the work easier and enable me to find the surface salinity. This salinity is usually measured on the base of properties of sea water conductivity. At with SST, surface salinity data is showing a good map over the region covered by the SailBuoy. From the figure, it is clear that during the study period the salinity range dominants between 36 and 36.5; but at the beginning we observe the range below 35.5. This lower range stabilized for only a few days, and then it went over 36 and kept this rate at a constant until the end of May 15.

Posted By:
Mahmud Hasan Ghani, Norwegian Meteorological Institute

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