A Climatological Study of Thermally Driven Wind Systems of the U.S. Intermountain West

Stewart, Jebb Q.; Whiteman, C. David; Steenburgh, W. James; Bian, Xindi

doi:10.1175/1520-0477(2002)083<0699:acsotd>2.3.co;2

Cited by 76 publications

(80 citation statements)

References 9 publications

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“…Terrain ruggedness had a very strong interaction, however, with TKE: ruggedness had large negative effects on distance traveled only at high values of TKE, suggesting that, on days with strong convective air-flow, ruggedness can act to decrease the spatiotemporal predictability of uplift and to decrease the coherent length scale of the spatial structure of thermal convection over rough terrain (e.g., ref. 26). The birds in this study primarily migrated along level ground where ruggedness is likely to disrupt otherwise predictable thermals, but other raptors that migrate along the Appalachian chain of mountains clearly benefit from the organizing effect of mountain ridges on wind-generated TKE (27) .…”

Section: Resultsmentioning

confidence: 84%

Movement ecology of migration in turkey vultures

Mandel

Bildstein

Bohrer

et al. 2008

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

114

143

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We develop individual-based movement ecology models (MEM) to explore turkey vulture (Cathartes aura) migration decisions at both hourly and daily scales. Vulture movements in 10 migration events were recorded with satellite-reporting GPS sensors, and flight behavior was observed visually, aided by on-the-ground VHF radio-tracking. We used the North American Regional Reanalysis dataset to obtain values for wind speed, turbulent kinetic energy (TKE), and cloud height and used a digital elevation model for a measure of terrain ruggedness. A turkey vulture fitted with a heart-rate logger during 124 h of flight during 38 contiguous days showed only a small increase in mean heart rate as distance traveled per day increased, which suggests that, unlike flapping, soaring flight does not lead to greatly increased metabolic costs. Data from 10 migrations for 724 hourly segments and 152 daily segments showed that vultures depended heavily upon high levels of TKE in the atmospheric boundary layer to increase flight distances and maintain preferred bearings at both hourly and daily scales. We suggest how the MEM can be extended to other spatial and temporal scales of avian migration. Our success in relating model-derived atmospheric variables to migration indicates the potential of using regional reanalysis data, as here, and potentially other regional, higher-resolution, atmospheric models in predicting changing movement patterns of soaring birds under various scenarios of climate and land use change.energetics ͉ flight ͉ meteorology T raditionally, bird migration has been treated separately relative to other movements within an individual's life history (1-2). Although long-distance migration operates on different scales and produces different patterns than those of other movement types in a bird's life cycle, there are also many similarities (cf. ref.3). As in other biotic movements, migration involves the assessment of internal state of the organism, external factors, and past behavior to make decisions about motion and navigation (4).One significant challenge of migration research is measuring the extent to which migratory routes and schedules of individual migrants are influenced by external factors, including wind direction and speed (5-6), food availability and habitat (2), and the behavior of other migrants (1, 7). One important axis of variation among migratory birds is the extent to which environmental factors act as facilitators of, as opposed to barriers to, movement. Determining the effects of environmental factors is particularly important for soaring birds, whose movements rely upon environmental factors such as deflection updrafts and thermal convection as their principle means of propulsion, whereas those using primarily flapping flight are, in principal, not directly dependent on environmental forces for propulsion and lift. Although we recognize that this categorization can be overly simplistic (see, for example, ref. 8) and that other categorizations based on ecological function exist (9-10), the dichoto...

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Section: Resultsmentioning

confidence: 84%

Movement ecology of migration in turkey vultures

Mandel

Bildstein

Bohrer

et al. 2008

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

114

143

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“…ac.uk/data/radiosonde/radhelp.html), the data were not temporally coincident and, therefore, did not improve our interpretation of wind patterns for the satellite tracks. Although topographic features such as valleys and slope angle will undoubtedly affect local wind conditions, anabatic/katabatic wind phenomena are common in every terrestrial mountain range on earth (19)(20)(21)(22)(23)(24)(25) and operate at the scale of mountain ranges, relevant to the migratory distance traveled by the geese. The Pyramid station data describe wind speed and direction at 30-min intervals for the year and cover the period over which we tracked birds migrating.…”

Section: Methodsmentioning

confidence: 99%

“…Large mountainous areas are characterized by daily slope winds that occur due to predictable changes in daily solar radiation and thermal conditions [e.g., the Alps (19,20), the Andes (21), the Himalaya (22,23), and mountainous areas in the United States (24,25)]. These winds reach an upslope "anabatic" maximum during the warmest part of the day, and a downslope, "katabatic" maximum in the evening and overnight (19,20).…”

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confidence: 99%

The trans-Himalayan flights of bar-headed geese ( Anser indicus )

Hawkes

Balachandran

Batbayar

et al. 2011

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

139

125

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Birds that fly over mountain barriers must be capable of meeting the increased energetic cost of climbing in low-density air, even though less oxygen may be available to support their metabolism. This challenge is magnified by the reduction in maximum sustained climbing rates in large birds. Bar-headed geese (Anser indicus) make one of the highest and most iconic transmountain migrations in the world. We show that those populations of geese that winter at sea level in India are capable of passing over the Himalayas in 1 d, typically climbing between 4,000 and 6,000 m in 7-8 h. Surprisingly, these birds do not rely on the assistance of upslope tailwinds that usually occur during the day and can support minimum climb rates of 0.8-2.2 km·h −1 , even in the relative stillness of the night. They appear to strategically avoid higher speed winds during the afternoon, thus maximizing safety and control during flight. It would seem, therefore, that bar-headed geese are capable of sustained climbing flight over the passes of the Himalaya under their own aerobic power.exercise physiology | high altitude | satellite tracking | vertebrate migration | climbing flight M ountains and high plateaus present formidable obstacles to the migratory flights of a number of bird species. Large birds, such as cranes and geese, may find such barriers particularly challenging as the sustained climbing rates of birds scale negatively with increasing body mass (1). For example, brent geese (Branta bernicla) are unable to sustain climbing flights over the Greenland icecap (summit elevation 3,207 m, mean elevation >2,000 m) and make regular stops to recover, possibly from partly anaerobic flights (2). Nevertheless, populations of bar-headed geese (Anser indicus) that spend the winter at sea level in India and the summer in central Asia must perform the world's steepest migratory flight north over the highest mountain range on earth, the Himalaya (3). There, most passes are at altitudes greater than 5,000 m, where the air density and partial pressure of oxygen are only about half of those at sea level. As a consequence, the partial pressure of oxygen (PO 2 ) in the arterial blood may begin to limit maximum performance (4, 5), although negative effects on the rate of oxygen diffusion may be partially ameliorated by an increase in the gas diffusion coefficient (6). The thinner air at these higher altitudes will also reduce lift generation during flapping flight for any given air speed, thus increasing the energy costs of flying by around 30% (7,8).However, bar-headed geese have adapted in a variety of ways for living and flying at high altitudes (4, 5). Their skeletal and cardiac muscles are better supplied with oxygen, having greater capillary density, more homogenous capillary spacing, a higher proportion of mitochondria in a subsarcolemmal location, and a greater proportion of oxidative fibers than other waterfowl (9, 10). Bar-headed goose hemoglobin is also highly effective at oxygen loading (11), compared with many other bird species, largel...

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“…4). Inspection of the wind direction data for all sites revealed a pattern representative of June, with westerly and southerly flow off the deserts toward Phoenix (Stewart et al 2002) almost all day, with only a couple of sites near the southeast mountains experiencing some nighttime reversals of wind that transitioned to southwest in the morning.…”

Section: Discussionmentioning

confidence: 99%

On the effects of landscape configuration on summer diurnal temperatures in urban residential areas: application in Phoenix, AZ

Kamarianakis

Turner

et al. 2017

Front. Earth Sci.

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Keywords: land architecture, urban heat island effect, NAIP, Phoenix, mixed-effects models AbstractThe impacts of land-cover composition on urban temperatures, including temperature extremes, are well documented. Much less attention has been devoted to the consequences of land-cover configuration, most of which addresses land surface temperatures. This study explores the role of both composition and configuration-or land system architecture-of residential neighborhoods in the Phoenix metropolitan area on near-surface air temperature. It addresses two-dimensional, spatial attributes of buildings, impervious surfaces, bare soil/rock, vegetation and the "urbanscape" at large, from 50 m to 550 m at 100 m increments, for a representative 30-day high sun period. Linear mixed-effects models evaluate the significance of land system architecture metrics at different spatial aggregation levels. The results indicate that, controlling for land-cover composition and geographical variables, land-cover configuration, specifically the fractal dimension of buildings, is significantly associated with near-surface temperatures. In addition, statistically significant predictors related to composition and configuration depend on the adopted level of spatial aggregation.

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A Climatological Study of Thermally Driven Wind Systems of the U.S. Intermountain West

Cited by 76 publications

References 9 publications

Movement ecology of migration in turkey vultures

Movement ecology of migration in turkey vultures

The trans-Himalayan flights of bar-headed geese ( Anser indicus )

On the effects of landscape configuration on summer diurnal temperatures in urban residential areas: application in Phoenix, AZ

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