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Longitude

About: Longitude is a research topic. Over the lifetime, 2260 publications have been published within this topic receiving 54988 citations. The topic is also known as: angle of longitude.


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Journal ArticleDOI
TL;DR: Variation in seed size in relation to latitude among and within perennial Glycine species across Australia was investigated and some intraspecific negative trends were found within G. canescens and G. cyrtoloba, which accords with Baker's hypothesis for an inverse relation between seed size and altitude.
Abstract: In the Northern Hemisphere, a latitudinal gradient of increasing seed size towards the equator has been well documented. Because of a paucity of studies from the Southern Hemisphere, however, the global generality of this latitudinal gradient in seed size is unknown. This study investigated variation in seed size in relation to latitude among and within perennial Glycine species across Australia. Seed size was estimated from over 1500 provenances covering the latitudinal, longitudinal and altitudinal extents of 37 taxa within the subgenus. In order to ensure that any observed latitudinal gradient in seed size existed independently of two other major geographic variables, longitude and altitude, we controlled for their influence via the use of general linear models. Among species, a significant negative relationship emerged between seed size and latitude when latitude was considered on its own and after accounting for the influence of longitude and altitude in models. For Australian populations of the subgenus Glycine, mean species seed size increased by 4.23% with each shift of one degree of latitude towards the equator and increased significantly along an east–west cline across the continent, by 2.25% with each degree of longitude. This latter relationship was obtained both when longitude was considered on its own and after controlling for the influence of latitude and altitude in models. Patterns of seed size variation with latitude and longitude within species mirrored patterns among species, although there were some notable exceptions. Altitude was significantly related to seed size among species only after removing the linear effects of latitude and longitude, when the trend was for lowland species to have smaller seeds. In contrast to the interspecific pattern, some intraspecific negative trends were found within G. canescens and G. cyrtoloba, which accords with Baker's hypothesis for an inverse relation between seed size and altitude. We discuss the relationships between seed size and the three geographic variables in the subgenus Glycine, with respect to environmental factors that could account for the trends detected.

39 citations

01 Jan 1999
TL;DR: In this paper, the authors examined temperature, salinity, and water masses of the Bering Sea, studying their vertical structure, temporal variability, and features of their spatial and temporal distribution.
Abstract: Data from 35,700 hydrographic stations were grouped in areas of 1° latitude and 2° longitude and monthly, seasonal, and annual means calculated. We examined temperature, salinity, and water masses of the Bering Sea, studying their vertical structure, temporal variability, and features of their spatial and temporal distribution. We also considered data from coastal observations, information on the meteorological regime, and river outflow.

39 citations

Journal ArticleDOI
TL;DR: In this paper, a two-layer crust was found, with velocities uniform both laterally and vertically within the layers, and a discontinuity separating the crustal layers (called the Intermediate discontinuity) is believed to be similar to the Conrad discontinuity.
Abstract: Deep seismic sounding of the earth's crust has been carried out between latitudes 49°30′ N and 51°30′ N, from longitude 93 °W to longitude 96 °W, by means of a refraction survey, using energy from underwater explosions. A two-layer crust was found, with velocities uniform both laterally and vertically within the layers. Velocities found were: Pg = 6.05 ± 0.05 km/s; Sg = 3.46 ± 0.05 km/s; P* = 6.85 ± 0.05 km/s; S* = 4.00 ± 0.05 km/s; Pn = 7.92 km/s; Sn = 4.60 ± 0.08 km/s. The discontinuity separating the crustal layers (called the Intermediate discontinuity) is believed to be similar to the Conrad discontinuity. Contour maps of depths to this discontinuity and the Mohorovicic discontinuity were produced. Average depths (below surface) are: Intermediate = 18.25 km; Mohorovicic = 34.28 km. Average surface elevation is 0.33 km. Velocity averaged vertically through the crust has a mean value over the area of 6.36 km/s. Structures on the discontinuities are related to at least one major surface geological featu...

39 citations

Journal ArticleDOI
TL;DR: In this paper, neutral atmospheric composition measurements were obtained by the Esro 4 gas analyzer during a series of geomagnetic storms in late February 1973 and combined with ground-based ionosonde data, these measurements show a complex latitudinal and longitudinal structure of the stormassociated disturbances in the upper atmosphere.
Abstract: Neutral atmospheric composition measurements were obtained by the Esro 4 gas analyzer during a series of geomagnetic storms in late February 1973. Complemented by ground-based ionosonde data, these measurements show a complex latitudinal and longitudinal structure of the storm-associated disturbances in the upper atmosphere. Specifically, a strong depression of the O/N2 ratio developed and persisted for several consecutive days above the Australian-African area. It was distinguished by a fairly sharp eastward boundary near 180°E longitude. This mid-latitude disturbance zone was distinctly separated from strongly disturbed regions at higher latitudes. It is suggested that the energy causing this mid-latitude disturbance was deposited primarily at altitudes below 150 km. Because of the long diffusion time constants in the lower thermosphere this can account for the persistence of the phenomena observed at F2 layer heights.

39 citations

Journal ArticleDOI
TL;DR: The attributes for the simulation of tropical intraseasonal oscillations in the 30 to 60 day range by three GCMs are compared with analyses of the European Center for Medium-Range Weather Forecasts as mentioned in this paper.
Abstract: The attributes for the simulation of tropical intraseasonal oscillations in the 30 to 60 day range by three GCMs are compared with analyses of the European Center for Medium-Range Weather Forecasts. Models under consideration include the Goddard Laboratory of Atmospheric sciences (GLAS), Goddard Laboratory for Atmospheres (GLA), and UCLA GCMs. They are characterized by the same resolutions of four degrees latitude by five degrees longitude with 9 levels. Observations reveal that the eastward traveling planetary scale structure becomes more stationary over the Indonesian region and accelerates over the Central Pacific. In the tropics a Kelvin wave-type structure is found to be dominant near the center of the oscillation. The simulated winds are realistic although the meridional component is too strong, especially in the GLA GCM. The differences in the structure of the oscillation in the GLAS GCM and GLA GCM are considered to be a consequence of the different numerical schemes used. The GCMs are characterized by preferred zones for diabatic heating, with a turn-on heating occurring when the rising branch of the intraseasonal oscillation passes over these convective regions.

39 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023240
2022432
202142
202042
201960
201851