NOAA Teacher at Sea Wes Struble Aboard NOAA Ship Ronald H. Brown February 15 - March 5, 2012
Mission: Western Boundary Time Series Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas Date: March 4, 2012 Weather Data from the Bridge Position:30 deg 37 min North Latitude & 79 deg 29 min West Longitude Windspeed: 30 knots Wind Direction: North Air Temperature: 14.1 deg C / 57.4 deg F Water Temperature: 25.6 deg C / 78.4 deg F Atm Pressure: 1007.2 mb Water Depth:740 meters / 2428 feet Cloud Cover: 85% Cloud Type: Cumulonimbus and Stratus Science/Technology Log: In the previous log I described a CTD cast in detail from start to finish. Now that the CTD platform is on the deck of the Ron Brown the actual sampling process can begin. The CTD has a number of Niskin bottles holding a little more than 10 liters of water each. Water samples from each bottle must be collected and analyzed for various parameters which could include: Salinity, Oxygen content, Inorganic carbon, and others. On this cruise most of the CTD casts were sampled for both salinity and dissolved oxygen. The first step in measuring salinity involves a careful rinsing of the sample bottles. After a standard three rinses, the bottle is filled and the depth from which the water was sampled is recorded for each bottle. [caption id="" align="aligncenter" width="474" caption="As a beautiful western Atlantic sunset falls on the Ron Brown another night of CTD's begins"]Image may be NSFW.Clik here to view.
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[caption id="attachment_9450" align="aligncenter" width="482" caption="I prepare a water sample for dissolved oxygen analysis after a CTD Cast at 2:00 am"]Image may be NSFW.Clik here to view.
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[caption id="attachment_9451" align="aligncenter" width="493" caption="The dissolved oxygen analysis lab station in one of the science labs on the Ron Brown"]Image may be NSFW.Clik here to view.
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The full sample bottles are then either taken to the dissolved oxygen lab station or the Salinity lab station for analysis.
[caption id="attachment_9452" align="aligncenter" width="489" caption="A close-up of the amperometric titration apparatus for analysis of dissolved oxygen in one of the science labs on the Ron Brown. A solution of Manganese Chloride and a combination of Sodium Hydroxide/Sodium Iodide is added to the water sample to sequester the oxygen and then when the temperature is stable the solution is amperometrically titrated with thiosulfate."]Image may be NSFW.Clik here to view.
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[caption id="attachment_9651" align="aligncenter" width="496" caption="The Ron Brown off the starboard stern from the workboat"]Image may be NSFW.Clik here to view.
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[caption id="attachment_9690" align="aligncenter" width="482" caption="The "climate airlock" leading to the salinity analysis lab. The airlock helps keep the water samples under constant temperature and humidity conditions."]Image may be NSFW.Clik here to view.
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[caption id="attachment_9750" align="aligncenter" width="530" caption="The two Autosals in the Salinity lab. These are precision instruments for measuring the salinity of seawater"]Image may be NSFW.Clik here to view.
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[caption id="attachment_9607" align="aligncenter" width="687" caption="A east-west cross-section across the eastern Atlantic Ocean. The eastern US coast is at left. The diagram illustrates north (reds)-south (blues) movement of the Antilles and Deep Western Boundary Current. Vertical scale in meters horizontal scale in 100,000 meter units (100 kilometers)"]Image may be NSFW.Clik here to view.
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