The experiment started in 1992 with first floats surfacing the same year. Numerous papers have been published analyzing the trajectories of floats that have completed their missions.
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The data include
61 quasi-Lagrangian subsurface trajectories sampled between 150 and 600 m. The following animation traces 15-day trajectory segments of the mid-depth floats. Right click to download the files.
View or Download AVI-file (~44MB)
View or Download MOV-file (~438MB) Download archive file (~16MB) These trajectories exhibite three patterns (Garfield et al., 1999):
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Sphagetti diagram of RAFOS float trajectories. |
| The westward migration of the floats is often accompanied by anticyclonic eddy-like motion. 45 "loopers" were visually identified. Each consisted of two or more consecutive loops with almost 80% moving westward at about 1.9 cm/s. |
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Anticyclonic loopers. Red dots show the points where a float was entrained by an eddy. |
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Along the coast, the
mean speed of the floats as well as principle axis of variance was alongshore.
Between Point Conception and Cape Mendocino the mean speed was 4±1 cm/s, with the mean flow vector oriented toward 329±17°
and the principle axis of variance directed toward 337±12°. These results are in good agreement with those obtained
by Garfield et al., (1999),
Garfield et al., (2001).
When calculating statistics from these data, one should keep in mind that estimates will be biased by array design (Garfield et al., 1999, Garfield et al., 2001). The alongshore and across-shore diffusivities were 230 and 580 cm²/s, respectively, for the Undercurrent region between Point Conception and Cape Mendocino. Garfield et al. (1999) pointed out an important mechanism for floats to enter the ocean interior from the undercurrent as formation of submesoscale coherent vortices (SCVs), which they referred to as California Undercurrent (CU) eddies or "cuddies". Although the dynamical effect of these cuddies on the CU is unclear, they are able to transport CU waters a long distance into the interior of the subtropical gyre. Lukas and Santiago-Mandujano (2001) observed a cuddy at the ALOHA time series site north of Oahu, Hawaii. |
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Eulerian mean velocity and variance ellipses. The box size is about one degree for both latitude and longitude. The units of the colorbar are cm/s and present the actual sizes of the principal axes of standard deviation. Numbers in the center of each ellipse are the number of measurements inside a corresponding box. |
In the work of Collins et al. (2003) the seasonal variabilities of the kinetic energy and eddy fields in the California Current System were estimated from the RAFOS floats deployed over 1998-2002. It was shown that the kinetic energy of the CU had two pronounced extrema in late spring and early fall, while the eddy field was especially intense in autumn. The same data set was used by Collins et al. (2004) to estimate the seasonal variability of the CU in three large geographical boxes that spanned the length of central and northern California and were located successively farther offshore. It was shown that the California Undercurrent occurred year-round in the coastal and transition zones which extended to 190 km offshore. Three different dispersive regimes of float motion were identified as ballistic transport, normal diffusion, and anomalous westward sub-diffusion, the last induced by Rossby wave-like structures.