Category: Physical Oceanography

Grant Rawson stabilizes the equipment as it is loaded onto the R/V F.G. Walton Smith. Image Credit: NOAA

Hydrographic Survey Conducted in the Florida Straits

PhOD personnel Ryan Smith, Grant Rawson, and Jay Hooper conducted a hydrographic survey along 27N in the Florida Straits aboard the R/V F.G. Walton Smith on January 12-13, 2015. The cruise was part of the Western Boundary Time Series project, which is designed to quantify Florida Current volume transport and water mass changes. This survey and others help to calibrate daily estimates of the Florida Current volume transport derived from a submarine telephone cable deployed across the Straits. Divers also exchanged a project pressure gauge on the west side of the 27N section.

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Time-longitude plots of (a) composite mean (CM) and (b and c) the two leading inter-event EOFs of the tropical Pacific SST anomalies averaged between 5°S and 5°N, for 21 El Ninos during 1949-2013. (d and e) Same as b and c except that the two EOFs are rotated by 90º. Units are in ºC. The dashed gray boxes indicate Nino 3.4 in DJF (0,+1), Nino 3 (150°W-90°W and 5°S-5°N) in AMJ (+1), Niño 3 in AMJ (0), and Niño 3.4 in OND (+1).

A new approach provides a holistic view of ENSO variability during the onset, peak and decay phases

From its onset to the decay, El Niño-Southern Oscillation (ENSO) plays an important role in forcing climate variability around the globe. A new study led by Sang-Ki Lee, a PhOD/CIMAS scientist, provides an efficient approach to explore the differences in the evolution of space-time patterns of sea surface temperature observed during El Niño events

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Science party aboard the Argentine research vessel ARA Puerto Deseado during a cruise to study the Meridional Overturning Circulation in the South Atlantic on October 4-16, 2014. Credit: SHN Argentina

Meridional Overturning Circulation: Following the Heat

If you want to understand Earth’s climate and how it changes from year-to-year and decade-to-decade, look to the oceans, and follow the heat. The major driver in the redistribution of heat around the globe in the ocean-climate system is Meridional Overturning Circulation, or MOC. The MOC is a vertical circulation pattern that exchanges surface and deep waters via poleward movement of surface waters. As an example, the well known Gulf Stream on the eastern seaboard of North America carries warm water northward to the Greenland and Norwegian Seas, where it cools and sinks.

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Evolution of the mean difference between the time the observation is taken to the time the profile is available at the Global Argo Data Assembly Centers. The reduction of the elapsed time at the beginning of 2012 are due to improvements of the processing system, while the reduction of the elapsed time at end of 2012 is due to switching operational data processing from once daily on an old computer to twice daily on a new and faster computer. Software and schedule changes in 2014 lead to further reductions of the elapsed time. Image Credit: NOAA AOML.

The US Argo Data Assembly Center improves the real-time processing system and adds new float types

The US Argo Data Assembly Center at PhOD used the transition to the NETCDF profile format version 3.0 to consolidate three processes into one process. This major development had multiple benefits. The primary benefit is that during the development stage the rapid changes in the float technology, for example the addition of sensors, were taken into account to increase the adaptability of the software to future changes of floats as well as the NETCDF profile format. Prior to this development, three programs required adaptation when float types with a new combination of sensors was deployed.

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Hurricane Scientists Bring a New Wave of Technology to Improve Forecasts

Scientists at NOAA’s Atlantic Oceanographic and Meteorological Laboratory are at the forefront of hurricane research to improve track and intensity forecasts. Every hurricane season they fly into storms, pour over observations and models, and consider new technological developments for how to enhance NOAA’s observing capabilities. The 2014 hurricane season will provide an opportunity to test some of the most advanced and innovative technologies, including unmanned hurricane hunter aircraft and sea gliders, which will help scientists better observe and, eventually, better predict a storm’s future activity.

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Kids Deploying Global Drifters

NOAA’s Array of Drifting Ocean Buoys

Drifting buoys are a primary tool used by the oceanographic community to measure ocean surface circulation at unprecedented resolution. A drifter is composed of a surface float, which includes a transmitter to relay data via satellite, and a thermometer that reads temperature a few centimeters below the air-sea interface. The surface float is tethered to a holey sock drogue (a.k.a. “sea anchor”), centered at 15 m depth. The drifter follows the ocean surface current flow integrated over the drogue depth.

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Altimetry-derived surface geostrophic currents (NOAA/AOML). Background color is the dynamic height. Image Credit: NOAA AOML.

Upcoming Observations with Underwater Gliders

Underwater glider SG610, deployed on July 14, is located in the Caribbean Sea. This glider navigated in a SW, then in a SE, and now in a SW direction since it was deployed. The temperature and salinity profile observations indicate that on July 25 this glider started sampling waters of a cyclonic eddy that is now centered at approximately 16.5°N, 67.5°W, and has a radius of ~0.75deg as derived from satellite altimetry observations. These profile observations show a decrease in the salinity maximum, and a shallowing of the depth of this maximum salinity and of the depth of the 26°C isotherm.

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