Yesterday we’ve recovered the last wave buoys after our last sampling station at about 42N, 64W. We went through one more weather system with overall more clement and warmer conditions. In other words it was smoother than St-Jude storm. We were even greeted by air and sea temperatures up to 20degC which is quite a change since we left Greenland! The sun has also been less shy over the last few days which made things a bit less gloomy.
Yesterday was also the day of our last Conductivity, Temperature, and Depth (CTD) sampling. The CTD is an instrument package used to compute seawater profiles of temperature, pressure, salinity and density. We also used it to get some near-surface and 500m-depth water samples to measure the background concentration of Dimethyl Sulfide (DMS) and Methanol in the ocean. This was a fun and entertaining activity to do twice a day and this especially when the ship was rolling a lot.
Retrieving the 43rd CTD. We managed to cross the tag lines on this final one.
The CTD dream team. From left to right: Byron, myself, Ming and Amy.
The last week on the ship has been mainly about discussing the status of our data analysis, working on inter-comparison between instruments and quality control of the data. Everyone is very happy with the data they have collected and with the conditions observed. We have harvested all the good ingredients we needed to successfully complete our mission: strong winds, good gas exchanges and wave properties. We made measurements in wind speeds above 15 m/s (33 knots) for a little bit over 20% of the duration of the project! Back on land all of us will start working on their respective post-processing and data analysis prior working all together again to assemble the different part of the puzzle and to answer our scientific questions. This will be a great step towards extending our knowledge of gas exchange and reducing our uncertainty in knowing how much the ocean is absorbing carbon dioxide (CO2).
Histogram of 5-min wind speed measured during this sampling campaign. About 24% of the wind measurements are above 15m/s or 33 knots.
The R/V Knorr is currently cruising at 11 knots towards Woods Hole, MA. During this last day at sea some of us started packing boxes, doing some more data analysis and writing cruise reports. The flux team will wait to be in port tomorrow to start packing as we have to lower the foremast to access our instruments. This will take us a couple of days to organize everything prior heading back home next week.
Heading back to Woods Hole, MA. Estimated Time of Arrival: 8am on November 14th.
I will end up this blog with a picture of dolphins that came along the ship today as a welcome home greeting. Thanks for reading my blog. I hope you have enjoyed this view into the life of a scientist at sea.
Dolphins swimming alongside the bow of the R/V Knorr. (Credit: Robin Pascal)
