scholarly journals Ecological Feedback Effects Affecting Arctic Biodiversity in Response to Glacial Melt

2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Almuneda Álvarez Fernández
Keyword(s):  
Geographic Region ◽  
The Arctic ◽  
The Sun ◽  
Summer Solstice ◽  
Winter Solstice ◽  
Feedback Effects ◽  
Arctic Circle ◽  
Imaginary Line

A changing Arctic The Arctic is a geographic region situated in the northernmost part of earth. It marks the latitude above which the sun does not set on the summer solstice and does not rise on the winter solstice. The Arctic is considered an area within the Arctic Circle that draws an imaginary line that …

Observation of the winter solstice 1812, with the mural circle at Greenwich

1832 ◽  
Vol 1 ◽  
pp. 457-457
Keyword(s):  
Slight Modification ◽  
The Sun ◽  
Summer Solstice ◽  
Winter Solstice ◽  
Separate Paper ◽  
The Subject

The weather was so extremely unfavourable, that it was not possible to obtain more than eight observations of the sun, from which the obliquity of the ecliptic at the late solstice could be deduced; from these it is inferred to have been 23° 27' 47''·35, that from the summer solstice having been 23° 27' 51''·3. This small discordance, it is observed, might be easily made to disappear by a slight modification of Bradley’s refractions; but the Astronomer Royal has not yet had an opportunity of making a sufficient number of observations on circumpolar stars with the new circle, to warrant making any corrections in his table of refractions, and he leaves the subject of the discordance of the solstices for discussion in a separate paper.

scholarly journals The results of observations made at the observatory of Trinity College, Dublin, for determining the obliquity of the ecliptic, and the maximum of the aberration of light

1833 ◽  
Vol 2 ◽  
pp. 114-115
Keyword(s):  
Trinity College ◽  
Sufficient Accuracy ◽  
Zenith Distance ◽  
The Sun ◽  
Summer Solstice ◽  
Winter Solstice ◽  
Trinity College Dublin ◽  
The Mean

The obliquity of the ecliptic, as deduced from the early observations by the Greenwich quadrant, compared with the present obliquity, gives the diminution for an interval of nearly sixty years, with almost sufficient accuracy to state with some confidence the mass of Venus; but to obtain this point with certainty, the present obliquity, deduced from a mean of the observations of different astronomers, should be used. Upon this subject the author alludes to the opinion of astronomers, that observations of the winter solstice have given a less obliquity than those of the summer solstice,—an opinion sustained by the observations of Maskelyne, Arago, and Pond, but questioned by Bessel and Bradley. Dr. Brinkley refers this difference to some unknown modification of refraction; he has observed that at the winter solstice the irregularity of refraction for the sun is greater than for the stars at the same zenith-distance. He points out the necessity of paying attention to the observations at the winter solstice, and gives a table, exhibiting the mean obliquity reduced to January 1813. Dr. Brinkley next alludes to the maximum of the aberration of light, which appears from his observations of last year to be 20"·80.

Mississippian Solstice Shrines and a Cahokian Calendar: An Hypothesis Based on Ethnohistory and Archaeology

1988 ◽  
Vol 8 (3) ◽  
pp. 227-247 ◽  
Author(s):  
Patricia J. O'Brien ◽  
William P. McHugh
Keyword(s):  
Full Moon ◽  
The Sun ◽  
Summer Solstice ◽  
The Moon ◽  
Winter Solstice ◽  
Vernal Equinox ◽  
Religious Ritual ◽  
Autumnal Equinox ◽  
New Moon ◽  
Using Data

This article examines the hypothesis that early Middle Mississippians had a calendric system which tied agriculture and religious ritual together. It also suggests that to that end they built solstice shrines as a means of recording the passage of time through the behavior of the sun and the moon. Using data from structures having possible astronomical alignments, from historic-ethnographic-linguistic sources, and from agricultural planting cycles, a “Cahokian calendar year” is constructed. The year begins with the summer solstice and the Great Busk ceremony. At the next full moon the “great corn” is planted to be harvested at the autumnal equinox. At the winter solstice winter begins while the vernal equinox is marked by a ritual for the Great Sun, their ruler. At the next new moon after that rite a “little corn” is planted which is harvested at the Great Busk. In their five-day, thirteenth month, just before the Busk, all the fires in the society are extinguished to be relit at the summer solstice Great Busk ceremony.

Sleep-Quality among Girls with Different Involvement in Competitive Sports during Fall in the Arctic Circle

1991 ◽  
Vol 73 (3) ◽  
pp. 883-892 ◽  
Author(s):  
Andi Weydahl
Keyword(s):  
High School ◽  
Sleep Quality ◽  
Significant Influence ◽  
The Arctic ◽  
Competitive Sports ◽  
The Sun ◽  
Arctic Circle ◽  
High School Girls ◽  
School Girls ◽  
Good Sleep

Eight high-school girls participating in competitive sports and six non-participating girls living north of the polar circle recorded their sleep once a week during the Fall, including the period when the sun does not rise above the horizon. Sleep-quality scores were computed as the sum of answers identical to a preset “right” answer indicating good sleep-quality. Significant differences on sleep-quality between the two groups were found, but a significant influence of amount of daylight or exercise could not be confirmed. When sleep-quality was ranked during three periods through the Fall, the girls participating in competitive sports showed a trend of increasing sleep-quality and the nonparticipants a decreasing one. An explanation based on influence of exercise thresholds upon sleep-quality is presented.

scholarly journals Angular properties of the solar light scattering in the terrestrial atmosphere observed by the ScanPol instrument of the AEROSOL-UA project

2020 ◽  
Vol 26 (6) ◽  
pp. 60-74
Author(s):  
V.O. Danylevsky ◽  
◽  
Keyword(s):  
Light Scattering ◽  
Local Time ◽  
Zenith Angle ◽  
Aerosol Particles ◽  
Lower Troposphere ◽  
Satellite Orbit ◽  
Solar Light ◽  
The Sun ◽  
Summer Solstice ◽  
Winter Solstice

Angular characteristics of solar light scattering in the Earth’s atmosphere and parameters of the atmosphere volume and the surface part observed by the ScanPol instrument of the “Aerosol-UA” project are estimated in order to determine properties of aerosol particles from a satellite orbit. Estimations were obtained for the scattering angles ranges in the lower troposphere which can be observed by the ScanPol instrument from the polar sun-synchronous orbit with altitude 705 km and inclination 98.1° crossing the ascending knot on the equator at 21h 30m, 22h 30m, and 23h 30m of local mean solar time. The estimations of the scattering angles were obtained at each of the orbit realizations for sites on the Earth’s surface, were the zenith angle of the Sun is 80°, 50°, and minimal one for each of the orbit realizations. The calculations were performed for the dates of 2020 close to the summer solstice, the autumnal equinox, and the winter solstice (namely 21 June, 21 September, and 21 December, respectively). The scattering angles range was computed for the range of the ScanPol scanning angles equal to 110° along the sub-satellite trace. The range of scattering angles is maximal at the considered here maximal zenith angle of the Sun equal to 80°, which occurs in the polar latitudes of the northern hemisphere during the period between the spring and the autumnal equinoxes and in the middle latitudes during the rest of a year. The maximal range of scattering angles is approximately 51.1°...149.5° close to the summer solstice for the satellite orbit with local time of crossing the ascending knot (TBB) equal to 21h 30m and 41.9°...172.9° for the orbit with ТВВ = 23h 30m. The minimal range of scattering angles occurs at minimal zenith angles of the Sun close to the winter solstice and takes on the values approximately 103.2°...142.8° and 108.2°...170.4° at mentioned ТВВ, respectively. For the rest of the zenith angles of the Sun, the range of scattering angles takes on the intermediate values. The range of scattering angles decreased mainly at the cost of small scattering angles. In summary, the range of observed scattering angles is maximal for the orbit with local time close to the noon, to be precise at TBB between 22h 30m and 24h 00m for the orbit with inclination assumed here. Comparison of the ranges of scattering angles observed by the ScanPol instrument and data of simulations showed that measurements by ScanPol from the considered orbit allow us to retrieve microphysical and optical properties of aerosol particles. Linear size of the scene observed by instrument along the sub-satellite trace increases during the scanning process from approximately 6 km at nadir to almost 60 km at maximal scattering angle equal to 60°, and simultaneously the longitude of the observed scene decreases by 1.55° that corresponds to linear shift along the parallel from DS »172 km on the equator to DS » 24.5 km on the latitude 82°. That is why data measured by the ScanPol can be used after mesoscale averaging.

Contributions to the discussion on astronomy in ancient literate societies

1974 ◽  
Vol 276 (1257) ◽  
pp. 117-121
Keyword(s):  
New World ◽  
The Other ◽  
Striking Difference ◽  
The Sun ◽  
Summer Solstice ◽  
Winter Solstice ◽  
Vernal Equinox ◽  
The Earth ◽  
The Hours ◽  
Autumnal Equinox

A. Digby (The Paddocks, Eastcombe, Stroud, Gloucestershire) I think the most striking difference between Old World and New World calendrical systems which has emerged from the papers today is the use in America of a 260-day period combining the 20 day names with the numerals 1 to 13. There is a possibility that the number thirteen may have been determined by the characteristics and shortcomings of a peculiar sundial which could be used to determine annual as well as diurnal time by showing the declination as well as the hour angle of the sun. The evidence for the existence of this instrument lies in examples of the year glyph which can be shown to be a drawing of two trapezes set at right angles on a ring. One lying north to south would cast a shadow which would move from west to east across the base of the instrument between the hours of about 7 a.m. and 5 p.m., while the other, a taller trapeze would cast a shadow that travels across the instrument in a direction from south to north and back reflecting the declination of the Sun. There is some evidence to show that the instrument was tilted with the base parallel to the axis of the Earth like a ‘polar sundial’ (paper read to a symposium on recent Mesoamerican research, Cambridge 1972). Under these conditions, the shadow would make four traverses of equal length in the course of the year: from the centre of the instrument to the northern extremity (autumnal equinox to winter solstice); north extremity to centre (winter solstice to vernal equinox); centre to south extremity (vernal equinox to summer solstice); south extremity to centre (summer solstice to autumnal equinox), each of 91J days duration.

scholarly journals An Other North: The Arctic Circle Summer Solstice Expedition 2017

2018 ◽  
Vol 43 (1) ◽  
pp. 53-62
Author(s):  
Brett Despotovich ◽  
Robert Hengeveld ◽  
Risa Horowitz ◽  
Brandy Leary ◽  
Lynne Quarmby ◽  
...  
Keyword(s):  
The Arctic ◽  
Summer Solstice ◽  
Arctic Circle ◽  
Biologie Moléculaire

Cette section Pratiques présente un aperçu du travail de six Canadiens, cinq artistes et une scientifique, qui en juin 2017 ont navigué le long des côtes ouest et nord du Svalbard, dans l’Arctique, dans le cadre de The Arctic Circle Summer Solstice Expedition. Cette expédition réunissait trente artistes, scientifiques, architectes et éducateurs, dont les pratiques englobent le dessin, les médias photographiques, les interventions in situ, la vidéo, la danse, la performance, l’écriture, les démarches sociales et la biologie moléculaire. Cette section témoigne de la nature interdisciplinaire, transdisciplinaire et multidisciplinaire des projets réalisés pendant l’expédition, ainsi que des multiples réflexions nées dans les mois suivants des discussions s’y étant déroulées. Encadrées par divers thèmes de projet, tels le deuil, la souveraineté, les catastrophes écologiques, les études nordiques et la cosmologie, les expériences collectives des participants, ainsi que les oeuvres qui en résultèrent, soulèvent des questions concernant les écologies humaines et leurs effets sur elles-mêmes et sur la planète entière.

scholarly journals XIII. Observations on the Mean Temperature of the Globe

1823 ◽  
Vol 9 (1) ◽  
pp. 201-225 ◽  
Author(s):  
David Brewster
Keyword(s):  
Direct Action ◽  
Temperate Zone ◽  
Full Measure ◽  
The Arctic ◽  
The Sun ◽  
Arctic Circle ◽  
The Earth ◽  
Mean Temperature ◽  
The Mean ◽  
Solar Rays

If no provision has been made by the Great Author of Nature, for equalising the light and heat projected upon the different bodies of our system, we may consider the earth as receiving, from the direct action of the solar rays, a degree of heat, intermediate between the condensed radiations sustained by Mercury and Venus, and the attenuated warmth which reaches the remoter planets. The heat which our Globe thus acquires from its locality in the system, is again tempered by the obliquity of its axis, and is distributed over the same parallels of latitude by its daily rotation. When the Sun is in the Equator, his rays, beating on the Earth with a vertical influence, impart to it the full measure of their action; and as his meridian altitude decreases, their intensity suffers a corresponding diminution. The burning heat at the Equator becomes moderated in higher latitudes. In passing through the temperate zone, it declines with great rapidity, and between the Arctic Circle and the Pole, the rays of the Sun are unable even to temper the piercing cold which reigns in these inhospitable regions.

scholarly journals EVALUATING THE SUN’S POSITION AND TRACKING THE SUN PATH FOR DUTSIN-MA, KATSINA STATE, NIGERIA

2020 ◽  
Vol 4 (3) ◽  
pp. 697-703
Author(s):  
Mustapha Shehu Mustapha ◽  
J. T. Baraya
Keyword(s):  
Solar Energy ◽  
Primary Data ◽  
Northwestern Part ◽  
The Sun ◽  
Summer Solstice ◽  
Solar Panels ◽  
Time Zone ◽  
Winter Solstice ◽  
Precise Position ◽  
Online Calculator

Solar energy is the most promising renewable energy source because of its free availability and an environmentally friendly source. The crucial applications of solar energy depend upon determining the precise position of the sun. In this research, we had made an attempt to determine the precise location of the sun for any topographical position of the earth using solar azimuth/altitude reckoner to track the path of the sun and related sun data. For the purpose of this work, we measured the position of Dutsin-Ma in Katsina State, Northwestern part of Nigeria. Solar online calculator (Keisan online calculator) was used to obtain primary data of sun’s (solar) angle parameters in order to calculate a series of variations in the azimuth and altitude angles using some inputs such as latitude, longitude, date, year, time and time zone. The results revealed that the maximum azimuth angles obtained from the sun are 294.38° for the winter solstice and 248.32° for the summer solstice with elevation angles of 79.01° and 53.46° respectively. Furthermore, the highest values of the hour angles were found to be 97.05° and 97.86° for the summer solstice and the winter solstice respectively. The findings of this work will help individual, government, and non-governmental organizations towards the utilization of solar energy and harnessing it especially during the installations of solar panels and other solar devices.  

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