The Autonomous Lagrangian Circulation Explorer (ALACE)

Davis, Russ E; Regier, L. A.; Dufour, J.; Webb, Doug

doi:10.1175/1520-0426(1992)009<0264:talce>2.0.co;2

Cited by 223 publications

(138 citation statements)

References 0 publications

Supporting

Mentioning

134

Contrasting

Unclassified

Order By: Relevance

“…Because of this, it has been found necessary to draw the position of the thermal STF (or temperature contrast structures with cooler water to the north, appraised from the images listed in Table 2) on three of the ¢gures for a clearer presentation of the STF position in relation to the distribution of subpolar and subtropical Mode Waters, the Lagrangian tracks in Storm 0 and the oceanic tracks in the STF region. Tracks from 11 drogued Argos buoys and three ALACE £oats (Davis et al, 1992) were superposed on the AVHRR imagery. Table 2 shows the track period (in year-days), the depth of the drogue for the ARGOS buoys and the mean pressure of the ALACE £oats.…”

Section: Methodsmentioning

confidence: 99%

Position and structure of the Subtropical/Azores Front region from combined Lagrangian and remote sensing (IR/altimeter/SeaWiFS) measurements

1999

View full text Add to dashboard Cite

The position and structure of the North Atlantic Subtropical Front is studied using Lagrangian flow tracks and remote sensing (AVHRR imagery: TOPEX/POSEIDON altimetry: SeaWiFS) in a broad region (∼31° to ∼36°N) of marked gradient of dynamic height (Azores Current) that extends from the Mid-Atlantic Ridge (MAR), near ∼40°W, to the Eastern Boundary (∼10°W). Drogued Argos buoy and ALACE tracks are superposed on infrared satellite images in the Subtropical Front region. Cold (cyclonic) structures, called ‘Storms’, and warm (anticyclonic) structures of 100–300 km in size can be found on the south side of the Subtropical Front outcrop, which has a temperature contrast of about 1°C that can be followed for ∼2500 km near 35°N. Warmer water adjacent to the outcrop is flowing eastward (Azores Current) but some warm water is returned westward about 300 km to the south (southern Counterflow). Estimates of horizontal diffusion in a Storm (D=2.2×102 m2 s−1) and in the Subtropical Front region near 200 m depth (Dx=1.3×104 m2 s−1, Dy=2.6×103 m2 s−1) are made from the Lagrangian tracks. Altimeter and in situ measurements show that Storms track westwards. Storms are separated by about 510 km and move westward at 2.7 km d−1. Remote sensing reveals that some initial structures start evolving as far east as 23°W but are more organized near 29°W and therefore Storms are about 1 year old when they reach the MAR (having travelled a distance of 1000 km). Structure and seasonality in SeaWiFS data in the region is examined.

show abstract

Section: Methodsmentioning

confidence: 99%

Position and structure of the Subtropical/Azores Front region from combined Lagrangian and remote sensing (IR/altimeter/SeaWiFS) measurements

1999

View full text Add to dashboard Cite

show abstract

“…Consequently, even weak oceanic subsurface currents are captured by the floats' paths (see Gould, 2005). Float trajectories can be established by either recording satellite fixes when floats surface at pre-programmed intervals (ALACE and APEX floats, Davis et al, 1992) or via triangulation of times of arrival of coded sound signals (SOFAR floats, Rossby and Webb, 1970;RAFOS floats, Rossby et al, 1986;MARVOR floats, Ollitrault et al, 1994). Floats located by means of satellite fixes must ascend periodically to the surface to transmit their data, which is why they are frequently called pop-up floats.…”

Section: Float Datamentioning

confidence: 99%

Lagrangian circulation of Antarctic Intermediate Water in the subtropical South Atlantic

Núñez‐Riboni

Boebel

Ollitrault

et al. 2005

Deep Sea Research Part II: Topical Studies in Oceanography

View full text Add to dashboard Cite

This study combines float data from different projects collected between 1991 and 2003 in the South Atlantic to describe the flow of Antarctic Intermediate Water (AAIW). Velocity space-time averages are calculated for various grid resolutions and with cells deformed to match the bathymetry, f/H or f/h (with H being the water depth and h being the thickness of the AAIW layer). When judged by the degree of alignment between respective isolines and the resulting average velocity fields, the best grid is based on a nominal cell size of 31 (latitude) by 41 (longitude) with cell shapes deformed according to f/h. Using this grid, objectively estimated mean currents (and their associated errors), as well as meridional and zonal volume transports are estimated. Results show an anticyclonic Subtropical Gyre centred near 361S and spanning from 23711S to 46711S. The South Atlantic Current meanders from 331S to 461S and shows a mean speed of 9.677.8 cm s À1 (8.573.5 Sv; 1 Sv ¼ 1 Â 10 6 m 3 s À1 ). The northern branch of the Subtropical Gyre is located between 221S and 321S and flows westward with a mean speed of 4.773.3 cm s À1 (9.373.4 Sv). Evidence of a cyclonic Tropical Gyre divided in two sub-cells is visible on the stream function. r

show abstract

“…The instrument design, called SOLO, is a new generation of Autonomous Langrangian Circulation Explorer (ALACE) floats [Davis et al, 1992] and is built at Scripps Institution of Oceanography. The units were programmed to drift at a depth of 1200 m for 7.5 days during each dive, followed by a surface interval of 12 hours.…”

Section: Deep Lagrangian Floatsmentioning

confidence: 99%