scholarly journals Continental patterns of bird migration linked to climate variability

2021 ◽  
Keyword(s):  
North America ◽  
Interannual Variability ◽  
Bird Migration ◽  
Low Frequency ◽  
Climatic Conditions ◽  
Eastern Region ◽  
Continental Scale ◽  
Oceanic Forcing ◽  
Migration Phenology ◽  
A Chain

Abstract For ˜100 years, the continental patterns of avian migration in North America have been described in the context of three or four primary flyways. This spatial compartmentalization often fails to adequately reflect a critical characterization of migration — phenology. This shortcoming has been partly due to the lack of reliable continental-scale data, a gap filled by our current study. Here, we leveraged unique radar-based data quantifying migration phenology and used an objective regionalization approach to introduce a new spatial framework that reflects interannual variability. Therefore, the resulting spatial classification is intrinsically different from the “flyway concept”. We identified two regions with distinct interannual variability of spring migration across the contiguous U.S. This data-driven framework enabled us to explore the climatic cues affecting the interannual variability of migration phenology, “specific to each region” across North America. For example, our “two-region” approach allowed us to identify an east-west dipole pattern in migratory behavior linked to atmospheric Rossby waves. Also, we revealed that migration movements over the western U.S. was inversely related to interannual and low-frequency variability of regional temperature. A similar link but weaker and only for interannual variability was evident for the eastern region. However, this region was more strongly tied to climate teleconnections, particularly to the East Pacific-North Pacific (EP-NP) pattern. The results suggest that oceanic forcing in the tropical Pacific—through a chain of processes including Rossby wave trains—controls the climatic conditions, associated with bird migration over the eastern U.S. Our spatial platform would facilitate better understanding of the mechanisms responsible for broad-scale migration phenology and its potential future changes.

scholarly journals Low-frequency variability of European runoff

2011 ◽  
Vol 15 (9) ◽  
pp. 2853-2869 ◽  
Author(s):  
L. Gudmundsson ◽  
L. M. Tallaksen ◽  
K. Stahl ◽  
A. K. Fleig
Keyword(s):  
Time Series ◽  
River Flow ◽  
Low Frequency ◽  
Space Time ◽  
Climatic Conditions ◽  
Continental Scale ◽  
Time Patterns ◽  
Frequency Components ◽  
The Impact ◽  
Precipitation And Temperature

Abstract. This study investigates the low-frequency components of observed monthly river flow from a large number of small catchments in Europe. The low-frequency components, defined as fluctuations on time scales longer than one year, were analysed both with respect to their dominant space-time patterns as well as their contribution to the variance of monthly runoff. The analysis of observed streamflow and corresponding time series of precipitation and temperature, showed that the fraction of low-frequency variance of runoff is on average larger than, and not correlated to, the fraction of low-frequency variance of precipitation and temperature. However, it is correlated with mean climatic conditions and is on average lowest in catchments with significant influence of snow. Furthermore, it increases (decreases) under drier (wetter) conditions – indicating that the average degree of catchment wetness may be a primary control of low-frequency runoff dynamics. The fraction of low-frequency variance of runoff is consistently lower in responsive catchments, with a high variability of daily runoff. The dominant space-time patterns of low-frequency runoff in Europe, identified using nonlinear dimension reduction, revealed that low-frequency runoff can be described with three modes, explaining together 80.6% of the variance. The dominant mode has opposing centres of simultaneous variations in northern and southern Europe. The secondary mode features a west-east pattern and the third mode has its centre of influence in central Europe. All modes are closely related to the space-time patterns extracted from time series of precipitation and temperature. In summary, it is shown that the dynamics of low-frequency runoff follows well known continental-scale atmospheric features, whereas the proportion of variance attributed to low-frequency fluctuations is controlled by catchment processes and varies with mean climatic conditions. The results may have implications for interpreting the impact of changes in temperature and precipitation on river-flow dynamics.

A bibliography for John Bachman

2005 ◽  
Vol 32 (1) ◽  
pp. 47-63
Author(s):  
G. Waddell
Keyword(s):  
North America ◽  
Natural History ◽  
Bird Migration ◽  
Wild Plants ◽  
Human Race ◽  
John James Audubon ◽  
The Reformation

John Bachman (1790–1874) was co-author with John James Audubon of The viviparous quadrupeds of North America (1842–1848). His other major books were The doctrine of the unity of the human race examined on the principles of science (1850) and A defense of Luther and the Reformation (1853). He wrote approximately 70 articles on topics ranging from religion to natural history including scientifi c methodology, wild plants, variation in domesticated plants and animals, hybrids, agriculture, bird migration and animal markings.

scholarly journals Release of Postsenescent Dormancy in Leafy Spurge (Euphorbia esula) by Chilling

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 784-786 ◽  
Author(s):  
Stephen J. Harvey ◽  
Robert M. Nowierski
Keyword(s):  
Growth Rate ◽  
North America ◽  
Growth And Development ◽  
Leafy Spurge ◽  
Climatic Conditions ◽  
Euphorbia Esula ◽  
Flower Buds ◽  
Significant Growth ◽  
Number Of Stems

The growth and development of leafy spurge (Euphorbia esulaL. #3EPHES) collected during postsenescent dormancy and grown in the greenhouse was increasingly stimulated by chilling treatments longer than 14 days duration at 0 to 6 C. Production of stems with flower buds, primary flowers, and secondary flowers was greater in plants chilled for 42 days or more. The effects of chilling on total number of stems, number of strictly vegetative stems, or number of stems with vegetative branching were not significant. The height of the tallest stem per pot was influenced by chilling longer than 42 days. Growth rate also increased as a function of chilling duration. Based on our findings, we believe that there is little possibility that any significant growth can occur in the postsenescent period because of the prevailing climatic conditions found in areas of leafy spurge distribution in North America.

Very low frequency electromagnetic phenomena: ‘whistlers’ and micropulsations

1977 ◽  
Vol 279 (963) ◽  
pp. 225-238 ◽  
Keyword(s):  
Low Frequency ◽  
Dynamical Behaviour ◽  
Weddell Sea ◽  
Particle Interactions ◽  
Terrestrial Environment ◽  
Wave Amplification ◽  
A Chain ◽  
Magnetic Conjugacy ◽  
Sea Area ◽  
The Antarctic

Observations of natural electromagnetic phenomena, embracing frequencies ranging from millihertz to tens of kilohertz, have made a major contribution to our knowledge of the terrestrial environment extending out to many Earth’s radii. The Antarctic has offered exceptional opportunities in this field for a number of reasons, including: (i) the location of Antarctic bases (including Halley Bay) at key magnetic latitudes, (ii) magnetic conjugacy to Northern Hemisphere thunderstorm sources, (iii) low interference levels. Important aspects of this research are the investigation of the role of wave-particle interactions in the magnetosphere and that of the structure and dynamical behaviour of the plasmapause, using both passive and active techniques. Comparisons of observations made at antarctic stations and their northern geomagnetic conjugates show close similarities in dominant pulsation periods and demonstrate the uniqueness of the Weddell Sea area in relation to magnetospheric wave amplification at the higher frequencies. An extra dimension to this work is being added, during the International Magnetospheric Study (1976-8), through the development of a chain of stations employing the goniometer (direction-finding) technique pioneered at Halley Bay by Sheffield University.

Study of the temperature regime of wheat storage In the elevator of the far eastern region of the Russian Federation

2020 ◽  
pp. 75-80
Author(s):  
V.V. Looze ◽  
A.V. Gavrilov ◽  
K.B. Gurieva ◽  
S.L. Beletskiy
Keyword(s):  
Russian Federation ◽  
Precast Concrete ◽  
Storage Period ◽  
Climatic Conditions ◽  
Eastern Region ◽  
Wheat Grain ◽  
Time Intervals ◽  
Temperature Changes ◽  
The Russian Federation ◽  
Far Eastern

The article presents and analyzes the temperature conditions of storage of wheat grain batches during the six-year storage period in silos of precast concrete elevators in the Far Eastern Region of the Russian Federation. The time intervals of grain temperature changes depending on the corresponding climatic conditions are considered. It is shown that the grain mass in the silos of elevators is in a cooled state, at a temperature below 10 °C, most of the annual cycle.

Further Notes on Structural Types and Earth Movements

1931 ◽  
Vol 68 (1) ◽  
pp. 15-24
Author(s):  
J. S. Lee
Keyword(s):  
South Africa ◽  
North America ◽  
Critical Points ◽  
Eastern China ◽  
Point Of View ◽  
Continental Scale ◽  
Structural Types ◽  
Tectonic Features ◽  
Geological Magazine

In a previous paper published in the Geological Magazine, the writer made an attempt to discuss the mechanism of earth movement on a continental scale purely from a tectonic point of view. The problem is so vast and involved that some of the vital points were hardly touched upon, partly because of lack of space and partly of literature. The arrival of the admirable works of Dr. A. du Toit and Dr. E. Krenkel has enabled the writer to deduce the mechanism of the movements of South Africa directly from its tectonic features, which process is thought to be far more reliable than the type of argument used in the previous case although the results arrived at are essentially the same. The earlier movements in North America are now seen to furnish evidence of the same type of mechanism as that which staged the later movements. An epsilon type of structure has been recognized in Eastern China, which was then described as a mere arc. The problem of the distribution of concealed coalfields in England was in the previous paper barely touched upon. It is now proposed to consider some of the critical points bearing on the problem.

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