Estimates of the Southern Ocean general circulation improved by animal‐borne instruments

Roquet, Fabien; Wunsch, Carl; Forget, Gaël; Heimbach, Patrick; Guinet, Christophe; Reverdin, Gilles; Charrassin, Jean‐Benoît; Bailleul, Frédéric; Costa, Daniel P.; Hückstädt, Luis A.; Goetz, Kimberly T.; Kovacs, Kit M.; Lydersen, Christian; Biuw, Martin; Nøst, Ole Anders; Bornemann, Horst; Ploetz, J.; Bester, Marthán N; McIntyre, Trevor; Muelbert, Mônica M. C.; Hindell, Mark A.; McMahon, Clive R.; Williams, Guy D.; Harcourt, Robert; Field, Iain C.; Chafik, Léon; Nicholls, Keith W.; Boehme, Lars; Fedak, Michael A.

doi:10.1002/2013gl058304

Cited by 119 publications

(126 citation statements)

References 20 publications

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“…This suggests that the bird-based wind estimates could be used to cover the satellite measurement gaps. In fact, geophysical data directly measured by instrumented animals or indirectly extracted from animal movements that complement conventional observation gaps have been assimilated to geophysical model analyses, as shown in currents extracted from shearwaters drift data (19) that were assimilated to ocean surface circulation models (20) and temperature and salinity profile measured by instrumented seals (11) used in Antarctic circumpolar circulation models (12). Wind stress and wind stress curl in coastal areas induce surface currents and upwelling systems that often generate areas of high biological productivity (6,8).…”

Section: Bird-based Wind Covers Spatial and Temporal Observation Gapsmentioning

confidence: 99%

“…For example, instrumented seals have been providing temperature and salinity profiles in the Antarctic Ocean for more than 10 y, especially under sea ice coverage that was difficult to measure by conventional methods (10,11). Adding these data to ocean circulation models improved the accuracy of estimated mixed layer properties (12). Bird-borne sensors are also used in measuring environmental variables such as temperature, depth, and light intensity directly from the instruments carried by the animal (13)(14)(15)(16).…”

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confidence: 99%

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Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction

Yonehara

Goto

Yoda

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Ocean surface winds are an essential factor in understanding the physical interactions between the atmosphere and the ocean. Surface winds measured by satellite scatterometers and buoys cover most of the global ocean; however, there are still spatial and temporal gaps and finer-scale variations of wind that may be overlooked, particularly in coastal areas. Here, we show that flight paths of soaring seabirds can be used to estimate fine-scale (every 5 min, ∼5 km) ocean surface winds. Fine-scale global positioning system (GPS) positional data revealed that soaring seabirds flew tortuously and ground speed fluctuated presumably due to tail winds and head winds. Taking advantage of the ground speed difference in relation to flight direction, we reliably estimated wind speed and direction experienced by the birds. These birdbased wind velocities were significantly correlated with wind velocities estimated by satellite-borne scatterometers. Furthermore, extensive travel distances and flight duration of the seabirds enabled a wide range of high-resolution wind observations, especially in coastal areas. Our study suggests that seabirds provide a platform from which to measure ocean surface winds, potentially complementing conventional wind measurements by covering spatial and temporal measurement gaps.biologging | dynamic soaring | satellite scatterometer | GPS | meteorology R ecently, remote-sensing systems used to record atmospheric circulation have been developed. Satellite-borne scatterometers estimate ocean surface wind velocities each day covering the majority of the global ocean. These wide-range wind data in combination with refined ocean models are used in numerical weather predictions and describe the oceanographic features more accurately (1-3). Buoys scattered over the ocean also measure fine-time resolution in situ surface winds and are used in validating remote-sensing measurements and are assimilated into model analyses (4, 5). However, because wind data are only acquired twice per day by each satellite and buoys have limited spatial coverage, finer-scale changes of hours to days in local wind conditions could be overlooked. In addition, in coastal areas, where high biological productivity is associated with ocean and atmosphere circulation patterns (6), wind data are lacking due to variations in wind and wave caused by complex topographic effects that satellites have difficulty measuring (5,7,8). Obtaining in situ high-resolution atmospheric and oceanographic data to fill these spatial and temporal observation gaps would deepen our understanding of physical processes relevant to interactions between the atmosphere and ocean, contribute to improved atmospheric and ocean model analyses (7,8), and reveal detailed structure that remains unresolved by using conventional methods (9).The recent development of miniaturized animal-borne data loggers presented a capability to use animals as indicators of environmental variables. The extensive movement range and locomotion ability of marine mammals and seabirds ena...

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Section: Bird-based Wind Covers Spatial and Temporal Observation Gapsmentioning

confidence: 99%

mentioning

confidence: 99%

Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction

Yonehara

Goto

Yoda

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Reality intrudes in several ways. For example, (a) the interior circulation is a complex of various physics (Wunsch & Heimbach 2013, Gray & Riser 2014, Thomas et al 2014, (b) much of the fluid in the observed Gulf Stream enters from the Southern Hemisphere and ultimately derives from everywhere (e.g., Schmitz & Richardson 1991), and (c) fluid entering the deep western boundary current from the north is rapidly recycled into the interior long before it moves very far latitudinally (e.g., Lozier 1997). The first issue has been addressed by deploying instruments across the entire ocean width at the Florida Straits latitude (through a program called RAPID; Rayner et al 2011).…”

Section: Transport Choke Pointsmentioning

confidence: 99%

Global Ocean Integrals and Means, with Trend Implications

Wunsch

2016

Annu. Rev. Mar. Sci.

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Understanding the ocean requires determining and explaining global integrals and equivalent average values of temperature (heat), salinity (freshwater and salt content), sea level, energy, and other properties. Attempts to determine means, integrals, and climatologies have been hindered by thinly and poorly distributed historical observations in a system in which both signals and background noise are spatially very inhomogeneous, leading to potentially large temporal bias errors that must be corrected at the 1% level or better. With the exception of the upper ocean in the current altimetric-Argo era, no clear documentation exists on the best methods for estimating means and their changes for quantities such as heat and freshwater at the levels required for anthropogenic signals. Underestimates of trends are as likely as overestimates; for example, recent inferences that multidecadal oceanic heat uptake has been greatly underestimated are plausible. For new or augmented observing systems, calculating the accuracies and precisions of global, multidecadal sampling densities for the full water column is necessary to avoid the irrecoverable loss of scientifically essential information.

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“…provides insight into the direct responses of individuals to their environment [38,53,54]. Since 2004, more than 270 000 CTD profiles were collected using CTD-SRDLs from SMRU (Sea Mammal Research Unit, St Andrews, Scotland) in the frame of SEaOS (Southern Elephant Seals as Oceanographic Samplers) and MEOP (Marine Mammal Exploration of the Oceans Pole to Pole; hooded, crabeater, Weddell and southern elephant seals) programs [55,56]. On average, two CTD profiles per day are transmitted and depending on the species the number of low-resolution dive profiles associated per day can be up to 15 more times (SES, Labrousse et al unpublished data).…”

Section: Ecological Applicationsmentioning

confidence: 99%

From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators

et al. 2015

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Background: In the last decade, thousands of satellite-relayed data loggers (SRDLs) have been deployed, providing large datasets on marine predator movement patterns at sea and their diving behaviour. However, the latter is in a highly summarised, low-resolution form, from which it is difficult to make the sorts of important behavioural inferences that are possible from higher-resolution datasets (such as detection of likely foraging events). The main objective of this study was to develop a simple, but accurate tool to detect and quantify within-dive foraging periods in low-resolution dives.Method: Two southern elephant seals were fitted with a head-mounted time depth recorder (TDR) (recording depth at 1 Hz) and an accelerometer (recording 3 axes of acceleration at 16 Hz) from which prey capture attempts were estimated (PrCA), and a Weddell seal was also fitted with a TDR (1 Hz).The resulting high-resolution dive profiles were used to: (1) calculate an accurate index of foraging effort based on the detection of vertical sinuosity switches (i.e. hunting highres time); (2) produce an SRDL-equivalent low-resolution dataset using a broken stick algorithm; and (3) from each low-resolution dive calculate a set of candidate foraging effort indices.Results: Hunting lowres time, which is the total time spent in decreased vertical velocity segments of the dive, was the foraging effort index that best correlated with hunting highres time. Hunting highres mode of SES dives (highly sinuous parts of high-resolution dives) was associated with 77 % of total PrCA. In comparison, Hunting lowres segments of SES dives were associated with 68 % of PrCA as well as with four times more PrCA than transit lowres segments. Conclusion:We found a low-resolution index which indicates foraging activity within a highly summarised dive profile and which identified most PrCA, despite degraded information transmitted by SLDRs. Used in combination with other measurements of the in situ environment, the hunting lowres index could be used in numerous integrated marine ecology studies, such as habitat use studies that are crucial to facilitate more effective conservation.

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Estimates of the Southern Ocean general circulation improved by animal‐borne instruments

Cited by 119 publications

References 20 publications

Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction

Flight paths of seabirds soaring over the ocean surface enable measurement of fine-scale wind speed and direction

Global Ocean Integrals and Means, with Trend Implications

From high-resolution to low-resolution dive datasets: a new index to quantify the foraging effort of marine predators

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