Tag: Rick Lumpkin

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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In-situ surface current velocity from ADCP (red vectors) and CTD station markers are shown for the July 2010 survey. Marker colors indicate the station θ-S profile classification as either GCW, LCW, EFCW, Coastal Shelf Water (green), or mixed-interleaved (black). Stations lacking waters denser than σθ = 24.0 kg m-3 are shown as small black dots. Prototype profile locations are indicated by an "x" and an enlarged marker. Letters identify selected sections along the cruise track. Image Credit: NOAA AOML.

Oceanographic conditions in the Gulf of Mexico in July 2010, during the Deepwater Horizon oil spill

Results from collaborative research conducted by AOML and NOAA’s Southeast Fisheries Science Center (SEFSC) in response to the 2010 Deepwater Horizon oil spill, were recently published in Continental Shelf Research (December, 2013). PhOD oceanographers R. Smith, E. Johns, G. Goni, J. Trinanes, and R. Lumpkin, in collaboration with other researchers at AOML (M. Wood, C. Kelble, and S. Cummings) and SEFSC (J. Lamkin and S. Privoznik) report on the surface and subsurface connectivity across the eastern Gulf of Mexico (GOM) during July 2010.

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Distribution of long-term mean observed (a)-(b) and simulated (c)-(d) meridional velocity along 23°W and 10°W. Gray dots in (a)-(b) indicate statistically significant values. Contour interval is 2.5 cm s-1. Figure reproduced from Perez et al., (2013). Image Credit: NOAA AOML.

Mean Meridional Currents in the Central and Eastern Equatorial Atlantic

In an article recently published in Climate Dynamics (Perez et al., 2013) , scientists in PhOD (R. Perez, R. Lumpkin, C. Schmid) described for the first time the mean vertical and cross-equatorial structure of the upper-ocean meridional currents in the Atlantic cold tongue region, using in situ observations including drifters, Argo, shipboard/lowered ADCP, and moored ADCP. This study involves collaborations with scientists from the University of Miami, Scripps Institution of Oceanography, and several international institutions and makes use of data from several major tropical Atlantic field programs including NOAA’s PIRATA Northeast Extension.

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Global Ocean Surface Velocities from Drifters: Mean, Variance, ENSO Response, and Seasonal Cycle

Using over 30 years of observations from drogued, satellite-tracked surface drifting buoys, Lumpkin and Johnson (2013) developed a methodology to map seasonally-varying surface currents at 1/2 degree resolution. Results from this study can be used to better understand how the ocean transports properties like heat, salt, and passive tracers, and serves as a reference to study changes in ocean currents over time. One key result from this study is the global distribution of mean, seasonal and eddy kinetic energy, which totals 4.6x1017J in the upper 30 m of the ocean and reveals the presence of three large eddy “deserts”, one in the Atlantic Ocean and the other two in the Pacific.

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