Measurements Of Thermal Updraft Intensity Over Complex Terrain Using American White Pelicans And A Simple Boundary-Layer Forecast Model

Shannon, Harlan D.; Young, George S.; Yates, Michael A.; Fuller, Mark R.; Seegar, William S.

doi:10.1023/a:1016095804357

Cited by 32 publications

(39 citation statements)

References 25 publications

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“…Therefore an obvious extension of Simsoar would be to provide the properties of thermal convection such as thermal depth and strength during the course of a day by incorporating a convection boundary layer model (Allen, 2006;Shamoun-Baranes et al, 2003a;Shannon et al, 2002b). To be effective, such a model would have to be tuned to the atmospheric conditions and landscape properties of the region of interest and checked independently from the other processes in Simsoar.…”

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confidence: 99%

Understanding soaring bird migration through interactions and decisions at the individual level

Loon

Shamoun‐Baranes

Bouten

et al. 2011

Journal of Theoretical Biology

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Many soaring bird species migrate southwards in autumn from their breeding grounds in Europe and Central Asia towards their wintering grounds. Our knowledge about interactions between migrating birds, thermal selection during migration and mechanisms that lead to flocking or convergent travel networks is still very limited. To start investigating these aspects we developed an individual-based simulation model that describes the local interactions between birds and their environment during their migratory flight, leading to emergent patterns at larger scales. The aim of our model is to identify likely decision rules with respect to thermal selection and navigation.After explaining the model, it is applied to analyse the migration of white storks (Ciconia ciconia) over part of its migration domain. A model base-run is accompanied by a sensitivity analysis. It appears that social interactions lead to the use of fewer thermals and slight increases in distance travelled. Possibilities for different model extensions and further model application are discussed.

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confidence: 99%

Understanding soaring bird migration through interactions and decisions at the individual level

Loon

Shamoun‐Baranes

Bouten

et al. 2011

Journal of Theoretical Biology

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“…This study shows that high-resolution GPS measurements of avian flight behavior can be used to collect information about meteorological conditions at a finescale and in areas where sensors are not available. Soaring birds, such as griffon vultures, are very efficient when circling in thermals (Pennycuick 1971;Shannon et al 2002b) and therefore provide unique measurements of vertical velocities in thermals. The strong correlation of the mean vertical velocity in a thermal with a modelresolved convective velocity scale is not surprising given mixed-layer similarity theory (Stull 1988).…”

Section: Discussionmentioning

confidence: 99%

“…1; a dynamic visualization can be found at www.doarama.com /view/433747). This type of flight will therefore be affected by the intensity of surface sensible heat flux and the atmospheric boundary layer depth, which determine the strength and altitude range of available thermal uplift (Shannon et al 2002a;ShamounBaranes et al 2003b;Mandel et al 2008). Several species use orographic uplift instead, thereby gliding for kilometers along mountain ridges (Shepard et al 2011;Bohrer et al 2012).…”

Section: Bird Flight Is Strongly Related To Meteorological Conditionsmentioning

confidence: 99%

“…However, obtaining quantitative information remained difficult until the invention of small altimeters and GPS devices. Shannon et al (2002b) showed that birdborne data can be used for obtaining quantitative meteorological observations. In their study, white pelicans (Pelecanus erythrorhynchos) were equipped with altimeters and tracked from the ground during cross-country flight.…”

Section: Bird Flight Is Strongly Related To Meteorological Conditionsmentioning

confidence: 99%

“…As we explained earlier, these estimates for the horizontal wind speed from the GPS locations are independent of sink rate. The vertical wind velocity is estimated from the sink rate added to the measured climb rate between two GPS fixes (Shannon et al 2002b). All equations can be found in the appendix to this paper.…”

Section: Estimation Of Wind Velocity and Convective Velocity Scale Frmentioning

confidence: 99%

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Using High-Resolution GPS Tracking Data of Bird Flight for Meteorological Observations

Treep

Bohrer

Shamoun‐Baranes

et al. 2016

Bulletin of the American Meteorological Society

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Bird flight is strongly influenced by local meteorological conditions. With increasing amounts of high-frequency GPS data of bird movement becoming available, as tags become cheaper and lighter, opportunities are created to obtain large datasets of quantitative meteorological information from observations conducted by bird-borne tags. In this article we propose a method for estimating wind velocity and convective velocity scale from tag-based high-frequency GPS data of soaring birds in flight. The flight patterns of soaring birds are strongly influenced by the interactions between atmospheric boundary layer processes and the morphology of the bird; climb rates depend on vertical air motion, flight altitude depends on boundary layer height, and drift off the bird’s flight path depends on wind speed and direction. We combine aerodynamic theory of soaring bird flight, the bird’s morphological properties, and three-dimensional GPS measurements at 3-s intervals to estimate the convective velocity scale and horizontal wind velocity at the locations and times of flight. We use wind speed and direction observations from meteorological ground stations and estimates of convective velocity from the Ocean–Land–Atmosphere Model (OLAM) to evaluate our findings. Although not collocated, our wind velocity estimates are consistent with ground station data, and convective velocity–scale estimates are consistent with the meteorological model. Our work demonstrates that biologging offers a novel alternative approach for estimating atmospheric conditions on a spatial and temporal scale that complements existing meteorological measurement systems.

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Wind estimation based on thermal soaring of birds

Weinzierl

Bohrer

Kranstauber

et al. 2016

Ecology and Evolution

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The flight performance of birds is strongly affected by the dynamic state of the atmosphere at the birds' locations. Studies of flight and its impact on the movement ecology of birds must consider the wind to help us understand aerodynamics and bird flight strategies. Here, we introduce a systematic approach to evaluate wind speed and direction from the high‐frequency GPS recordings from bird‐borne tags during thermalling flight. Our method assumes that a fixed horizontal mean wind speed during a short (18 seconds, 19 GPS fixes) flight segment with a constant turn angle along a closed loop, characteristic of thermalling flight, will generate a fixed drift for each consequent location. We use a maximum‐likelihood approach to estimate that drift and to determine the wind and airspeeds at the birds' flight locations. We also provide error estimates for these GPS‐derived wind speed estimates. We validate our approach by comparing its wind estimates with the mid‐resolution weather reanalysis data from ECMWF, and by examining independent wind estimates from pairs of birds in a large dataset of GPS‐tagged migrating storks that were flying in close proximity. Our approach provides accurate and unbiased observations of wind speed and additional detailed information on vertical winds and uplift structure. These precise measurements are otherwise rare and hard to obtain and will broaden our understanding of atmospheric conditions, flight aerodynamics, and bird flight strategies. With an increasing number of GPS‐tracked animals, we may soon be able to use birds to inform us about the atmosphere they are flying through and thus improve future ecological and environmental studies.

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Measurements Of Thermal Updraft Intensity Over Complex Terrain Using American White Pelicans And A Simple Boundary-Layer Forecast Model

Cited by 32 publications

References 25 publications

Understanding soaring bird migration through interactions and decisions at the individual level

Understanding soaring bird migration through interactions and decisions at the individual level

Using High-Resolution GPS Tracking Data of Bird Flight for Meteorological Observations

Wind estimation based on thermal soaring of birds

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