The geographical scale factor in orientation of migrating birds

1996 ◽  
Vol 199 (1) ◽  
pp. 9-19 ◽  
Author(s):  
T Alerstam
Keyword(s):  
Large Scale ◽  
Position Control ◽  
The Arctic ◽  
Detailed Knowledge ◽  
Migration Routes ◽  
Continental Scale ◽  
Ice Cap ◽  
Geographical Scale ◽  
Course Changes ◽  
Migrating Birds

Migration routes of birds throw light on orientation performance at different geographic scales, over distances ranging from a few kilometres to more than 104 km. Detailed knowledge about the flight routes may be used to test predictions about optimal orientation according to theoretical principles and about the use of compasses based on celestial or magnetic cues. Ringing recoveries demonstrate that the migratory journey of many species, such as the wheatear and willow warbler, is divided into successive legs with different main orientation. Autumn and spring migration routes are often different, sometimes diverging on a continental scale. Aerial radiotracking of whooping cranes in North America and satellite tracking of brent geese migrating from Iceland across the Greenland ice cap point to the significant role of large-scale topography for the shaping of migration routes. Compass and position control are also required, e.g. during long passages across featureless sea or ice, but how these elements are integrated into the birds' orientation system remains unclear. Radar studies from the Arctic Ocean illustrate the importance of map projections for interpreting flight paths and suggest that birds accomplish approximate great circle orientation. Gradual course changes shown by migrating knots monitored by radar in Scandinavia are at variance with expected changes if the birds were to use a star, sun or magnetic compass over longer distances. Accurate recording of short flight segments shows how flying birds respond to visual, audible and electromagnetic cues, and also documents orientation precision and capacity to integrate rapidly shifting courses into a consistent resulting orientation. Analyses of flight patterns are crucial for understanding how birds find and follow their migration routes over different ranges of geographical scale.

scholarly journals Polar forests on the edge of extinction: what does the fossil spore and pollen evidence from East Antarctica say?

2009 ◽  
Vol 22 (2) ◽  
pp. 57 ◽  
Author(s):  
E. M. Truswell ◽  
M. K. Macphail
Keyword(s):  
Ross Sea ◽  
Late Eocene ◽  
East Antarctica ◽  
The Arctic ◽  
Prydz Bay ◽  
Conifer Forest ◽  
Migration Routes ◽  
Ocean Drilling Program ◽  
Ice Cap ◽  
Growing Seasons

Diverse pollen and spore assemblages, spanning the Late Eocene preglacial–glacial transition, have been recovered from Ocean Drilling Program cores from Prydz Bay, East Antarctica. These microfloras are mostly in situ and provide an unparalleled record of terrestrial plant communities growing in Antarctica during the earliest stages of ice-cap formation. The evidence provides a basis for assessing the phytogeographic relationships of the Antarctic floras with other high-latitude floras in the southern hemisphere, including possible migration routes for some taxa. Preliminary studies (Macphail and Truswell 2004a) suggested the Late Eocene vegetation at Prydz Bay was floristically impoverished rainforest scrub, similar to Nothofagus–gymnosperm communities found near the climatic treeline in Patagonia and Tasmania. Re-evaluation of the microfloras indicates the diversity of shrubs, especially Proteaceae, was underestimated and the Late Eocene vegetation was a mosaic of dwarfed (krumholtz) trees, scleromorphic shrubs and wetland herbs, analogous to the taiga found in the transition zone between the boreal conifer forest and tundra biomes across the Arctic Circle. Microfloras similar to although much less diverse than the Prydz Bay assemblages occur in coreholes from the Ross Sea region on the opposite side of Antarctica. Interpretation of the latter is complicated by reworking and low yields but the combined evidence points to the collapse of taller woody ecosystems during the Eocene–Oligocene transition and their replacement by tundra-like or fell-field vegetation during the Oligocene and Neogene. This temperature-forced regression seems to have been broadly synchronous across the continent. The high-palaeolatitude location (~70°S) means that the Prydz Bay flora was adapted to several months of winter darkness and short-summer growing seasons. The nearest living relatives of identifiable woody taxa suggest year-round high humidity, with an annual precipitation between ~1200 and 1500 mm. Palaeotemperatures are more difficult to quantify although the inferred humid microtherm climate is consistent with mean annual temperatures less than 12°C and freezing winters.

scholarly journals Evaluation of Long-Distance Orientation in Birds on the Basis of Migration Routes Recorded by Radar and Satellite Tracking

2001 ◽  
Vol 54 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Thomas Alerstam
Keyword(s):  
Large Scale ◽  
Satellite Tracking ◽  
Polar Regions ◽  
High Latitudes ◽  
Migration Routes ◽  
Long Distance ◽  
Sun Compass ◽  
Branta Bernicla ◽  
Migrating Birds ◽  
East West

Predicted flight trajectories differ depending on which orientation cues are used by migrating birds. Results from radar and satellite tracking of migrating birds can be used to test which of the predicted trajectories shows the best fit with observed flight routes, supporting the use of the associated orientation mechanism. Radar studies of bird migration at the Northeast Passage and the Northwest Passage support the occurrence of migration along sun compass routes in these polar regions. In contrast, satellite tracking of Brent geese (Branta bernicla) migrating from Iceland across Greenland and from Northwest Europe to Siberia show routes that conform most closely with geographic loxodromes, but which are also profoundly influenced by large-scale topography. These evaluations are discussed in relation to the adaptive values of different routes in different parts of the world. Sun compass routes are favourable mainly for east-west migration at high latitudes. For east-west migration at mid and high latitudes magnetic loxodromes are more favourable than geographic loxodromes in certain regions while the reverse holds in other regions. The geometry of migration routes, as recorded by radar and satellite tracking, may be important for understanding the evolution of the complexity of birds' orientation systems, and for providing clues about the orientation mechanisms guiding the birds on their global journeys.

scholarly journals Role of wild animals in epizootology of infectious diseases inYakutia

2021 ◽  
Author(s):  
M.P. Neustroev ◽  
K.P. Yurov ◽  
N.P. Tarabukina ◽  
S.V. Alekseyenkova ◽  
A.M. Stepanova
Keyword(s):  
Infectious Diseases ◽  
Large Scale ◽  
Yersinia Pseudotuberculosis ◽  
Roe Deer ◽  
Natural Habitat ◽  
Central Zone ◽  
The Arctic ◽  
Wild Animals ◽  
Migration Routes ◽  
Wild Mammals

It is known that wild animals and birds can be reservoirs and carriers of many infectious diseases of animals and humans. A cadastre of disadvantaged anthrax settlements was developed based on the study of epizootology, which will help optimize epizootological and epidemiological measures for the prevention of anthrax in animals (wild and domestic) and the population. We first identified yersinia (Yersinia enterocolitica and Yersinia pseudotuberculosis) from the material for shooting moose and roe deer living in the Central zone of Yakutia. Antibodies to the serogroups Leptospira Pomona, Grippotyphosa, and Icterohaemorrhagiae serogroups were detected in forest bisons exported from Canada to Yakutia for acclimatization. We developed a method for sampling frozen urine with snow at low temperatures (minus 10-50 ?С) to diagnose leptospirosis of wild animals and dogs, in places of natural habitat of wild mammals (without seizure and capture). The bactericidal effect of the probiotic strains of bacteria Bacillus subtilis TNP-3 and TNP-5 on the causative agent of leptospirosis of various serological groups has been established. The methods are protected by the Russian Federation patents for the invention. There was marked disease and mortality of roe deer from salmonellosis caused by Sal. abortus equi. There has been established the circulation of viruses of infectious rhinotracheitis, diarrhea in the deer population of the Arctic regions, the causative agents of which may be migratory birds and animals of the disadvantaged settlements. In the period of intensive exploration of Actica, climate warming and changes in the fauna, the migration routes of wild animals and birds, growing threat of zoonoses it is necessary to conduct large-scale monitoring of infections, especially viral diseases.

scholarly journals Ice-Breaking Fleets of the United States and Canada: Assessing the Current State of Affairs and Future Plans

2021 ◽  
Vol 13 (2) ◽  
pp. 703
Author(s):  
Megan Drewniak ◽  
Dimitrios Dalaklis ◽  
Anastasia Christodoulou ◽  
Rebecca Sheehan
Keyword(s):  
United States ◽  
The United States ◽  
Maritime Transportation ◽  
The Arctic ◽  
Polar Ice ◽  
Northwest Passage ◽  
Ice Cap ◽  
Ice Coverage ◽  
Current State ◽  
State Of Affairs

In recent years, a continuous decline of ice-coverage in the Arctic has been recorded, but these high latitudes are still dominated by earth’s polar ice cap. Therefore, safe and sustainable shipping operations in this still frozen region have as a precondition the availability of ice-breaking support. The analysis in hand provides an assessment of the United States’ and Canada’s polar ice-breaking program with the purpose of examining to what extent these countries’ relevant resources are able to meet the facilitated growth of industrial interests in the High North. This assessment will specifically focus on the maritime transportation sector along the Northwest Passage and consists of four main sections. The first provides a very brief description of the main Arctic passages. The second section specifically explores the current situation of the Northwest Passage, including the relevant navigational challenges, lack of infrastructure, available routes that may be used for transit, potential choke points, and current state of vessel activity along these routes. The third one examines the economic viability of the Northwest Passage compared to that of the Panama Canal; the fourth and final section is investigating the current and future capabilities of the United States’ and Canada’s ice-breaking fleet. Unfortunately, both countries were found to be lacking the necessary assets with ice-breaking capabilities and will need to accelerate their efforts in order to effectively respond to the growing needs of the Arctic. The total number of available ice-breaking assets is impacting negatively the level of support by the marine transportation system of both the United States and Canada; these two countries are facing the possibility to be unable to effectively meet the expected future needs because of the lengthy acquisition and production process required for new ice-breaking fleets.

scholarly journals Effects of Climatic Drivers and Teleconnections on Late 20th Century Trends in Spring Freshet of Four Major Arctic-Draining Rivers

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 179
Author(s):  
Roxanne Ahmed ◽  
Terry Prowse ◽  
Yonas Dibike ◽  
Barrie Bonsal
Keyword(s):  
Arctic Ocean ◽  
Large Scale ◽  
Southern Oscillation ◽  
Rate Of Change ◽  
The Arctic ◽  
Late 20Th Century ◽  
Basin Scale ◽  
The Arctic Ocean ◽  
Spring Freshet ◽  
Climatic Drivers

Spring freshet is the dominant annual discharge event in all major Arctic draining rivers with large contributions to freshwater inflow to the Arctic Ocean. Research has shown that the total freshwater influx to the Arctic Ocean has been increasing, while at the same time, the rate of change in the Arctic climate is significantly higher than in other parts of the globe. This study assesses the large-scale atmospheric and surface climatic conditions affecting the magnitude, timing and regional variability of the spring freshets by analyzing historic daily discharges from sub-basins within the four largest Arctic-draining watersheds (Mackenzie, Ob, Lena and Yenisei). Results reveal that climatic variations closely match the observed regional trends of increasing cold-season flows and earlier freshets. Flow regulation appears to suppress the effects of climatic drivers on freshet volume but does not have a significant impact on peak freshet magnitude or timing measures. Spring freshet characteristics are also influenced by El Niño-Southern Oscillation, the Pacific Decadal Oscillation, the Arctic Oscillation and the North Atlantic Oscillation, particularly in their positive phases. The majority of significant relationships are found in unregulated stations. This study provides a key insight into the climatic drivers of observed trends in freshet characteristics, whilst clarifying the effects of regulation versus climate at the sub-basin scale.

Quantitative feedback controller design and test for an electro-hydraulic position control system in a large-scale reflecting telescope

2017 ◽  
Vol 18 (10) ◽  
pp. 1624-1634 ◽  
Author(s):  
Xiong-bin Peng ◽  
Guo-fang Gong ◽  
Hua-yong Yang ◽  
Hai-yang Lou ◽  
Wei-qiang Wu ◽  
...  
Keyword(s):  
Control System ◽  
Large Scale ◽  
Position Control ◽  
Controller Design ◽  
Feedback Controller ◽  
Position Control System

Large scale magnetic anomalies over western Canada and the Arctic: a discussion

1976 ◽  
Vol 13 (6) ◽  
pp. 790-802 ◽  
Author(s):  
R. L. Coles ◽  
G. V. Haines ◽  
W. Hannaford
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Elevated Temperatures ◽  
Magnetic Anomalies ◽  
The Arctic ◽  
Evolutionary Development ◽  
Magnetic Feature ◽  
Western Canada ◽  
Arctic Regions ◽  
The Magnetic Field

A contoured map of vertical magnetic field residuals (relative to the IGRF) over western Canada and adjacent Arctic regions has been produced by amalgamating new data with those from previous surveys. The measurements were made at altitudes between 3.5 and 5.5 km above sea level. The map shows the form of the magnetic field within the waveband 30 to 5000 km. A magnetic feature of several thousand kilometres wavelength dominates the map, and is probably due in major part to sources in the earth's core. Superimposed on this are several groups of anomalies which contain wavelengths of the order of a thousand kilometres. The patterns of the short wavelength anomalies provide a broad view of major structures and indicate several regimes of distinctive evolutionary development. Enhancement of viscous magnetization at elevated temperatures may account for the concentration of intense anomalies observed near the western edge of the craton.

FPGA-Based Intelligent Software Hardening Chip for Computer Numerical Control System

2011 ◽  
Vol 105-107 ◽  
pp. 2217-2220
Author(s):  
Mu Lan Wang ◽  
Jian Min Zuo ◽  
Kun Liu ◽  
Xing Hua Zhu
Keyword(s):  
High Speed ◽  
High Performance ◽  
Large Scale ◽  
Position Control ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Cnc System ◽  
Intelligent Software

In order to meet the development demands for high-speed and high-precision of Computer Numerical Control (CNC) machine tools, the equipped CNC systems begin to employ the technical route of software hardening. Making full use of the advanced performance of Large Scale Integrated Circuits (LSIC), this paper puts forward using Field Programmable Gates Array (FPGA) for the functional modules of CNC system, which is called Intelligent Software Hardening Chip (ISHC). The CNC system architecture with high performance is constructed based on the open system thought and ISHCs. The corresponding programs can be designed with Very high speed integrate circuit Hardware Description Language (VHDL) and downloaded into the FPGA. These hardening modules, including the arithmetic module, contour interpolation module, position control module and so on, demonstrate that the proposed schemes are reasonable and feasibility.

scholarly journals Analog Downscaling of Seasonal Rainfall Forecasts in the Murray Darling Basin

2013 ◽  
Vol 141 (3) ◽  
pp. 1099-1117 ◽  
Author(s):  
Andrew Charles ◽  
Bertrand Timbal ◽  
Elodie Fernandez ◽  
Harry Hendon
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Seasonal Prediction ◽  
General Circulation Models ◽  
Meridional Wind ◽  
Seasonal Forecasts ◽  
Local Climate ◽  
Continental Scale ◽  
Predictive Skill ◽  
Murray Darling Basin

Abstract Seasonal predictions based on coupled atmosphere–ocean general circulation models (GCMs) provide useful predictions of large-scale circulation but lack the conditioning on topography required for locally relevant prediction. In this study a statistical downscaling model based on meteorological analogs was applied to continental-scale GCM-based seasonal forecasts and high quality historical site observations to generate a set of downscaled precipitation hindcasts at 160 sites in the South Murray Darling Basin region of Australia. Large-scale fields from the Predictive Ocean–Atmosphere Model for Australia (POAMA) 1.5b GCM-based seasonal prediction system are used for analog selection. Correlation analysis indicates modest levels of predictability in the target region for the selected predictor fields. A single best-match analog was found using model sea level pressure, meridional wind, and rainfall fields, with the procedure applied to 3-month-long reforecasts, initialized on the first day of each month from 1980 to 2006, for each model day of 10 ensemble members. Assessment of the total accumulated rainfall and number of rainy days in the 3-month reforecasts shows that the downscaling procedure corrects the local climate variability with no mean effect on predictive skill, resulting in a smaller magnitude error. The amount of total rainfall and number of rain days in the downscaled output is significantly improved over the direct GCM output as measured by the difference in median and tercile thresholds between station observations and downscaled rainfall. Confidence in the downscaled output is enhanced by strong consistency between the large-scale mean of the downscaled and direct GCM precipitation.

scholarly journals The large-scale energy budget of the Arctic

2007 ◽  
Vol 112 (D11) ◽  
Author(s):  
Mark C. Serreze ◽  
Andrew P. Barrett ◽  
Andrew G. Slater ◽  
Michael Steele ◽  
Jinlun Zhang ◽  
...  
Keyword(s):  
Energy Budget ◽  
Large Scale ◽  
The Arctic
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