scispace - formally typeset
Search or ask a question
Topic

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.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors applied the principal component analysis (PCA) technique to the vertical total electron content (VTEC) from global International GNSS Service (IGS) in order to analyze the temporal and spatial variations of the ionosphere during noon and night in far-from-magnetic pole regions, during a 3-year period at high (2000-2002) and low (2006-2008) solar activity conditions.
Abstract: The Weddell Sea Anomaly (WSA) is defined when the nighttime plasma density is greater than the daytime density in the area near the Weddell Sea, more specifically in the region limited by 50° S–70° S in latitude and 225° E–315° E in longitude. A similar ionospheric anomaly is also observed near the Okhotsk Sea in the northern hemisphere, and such a feature was named as Okhotsk Sea Anomaly (OSA). The objective of this work is to infer possible physical causes of the WSA and OSA phenomena. To that end, we applied the principal component analysis (PCA) technique to the vertical total electron content (VTEC) from global International GNSS Service (IGS) in order to analyze the temporal and spatial variations of the ionosphere during noon and night in far-from-magnetic pole regions, during a 3-year period at high (2000–2002) and low (2006–2008) solar activity conditions. The first mode of PCA applied on VTEC scattering represents on average the 93 % of the total VTEC variability. Thus, the PCA expansions up to mode 1 resulted enough to show WSA and OSA during summer solstices in both solar activity conditions, as well as WSA during spring equinox during low solar activity. Besides, the analysis of the temporal variations of these first modes should provide the interpretation of a probable physical explanation to the observed anomalies. We conclude that the main contributors to the anomalies should be a combination of the same physical mechanisms that explain annual variation and semiannual anomaly in that regions located far from the magnetic poles.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present radio continuum data at 408 MHz over the area 52 degrees < longitude < 193 degrees, -6.5 degrees < latitude < 8.5 degree, with an extension to latitude = 21 degrees in the range 97 degrees > longitude > 120 degrees, with angular resolution 2.8' x 2' cosec(declination).
Abstract: The interstellar medium is a complex 'ecosystem' with gas constituents in the atomic, molecular, and ionized states, dust, magnetic fields, and relativistic particles. The Canadian Galactic Plane Survey has imaged these constituents with angular resolution of the order of arcminutes. This paper presents radio continuum data at 408 MHz over the area 52 degrees < longitude < 193 degrees, -6.5 degrees < latitude < 8.5 degrees, with an extension to latitude = 21 degrees in the range 97 degrees < longitude < 120 degrees, with angular resolution 2.8' x 2.8' cosec(declination). Observations were made with the Synthesis Telescope at the Dominion Radio Astrophysical Observatory as part of the Canadian Galactic Plane Survey. The calibration of the survey using existing radio source catalogs is described. The accuracy of 408-MHz flux densities from the data is 6%. Information on large structures has been incorporated into the data using the single-antenna survey of Haslam (1982). The paper presents the data, describes how it can be accessed electronically, and gives examples of applications of the data to ISM research.

11 citations

Journal ArticleDOI
TL;DR: Astrometric results of CCD observations of the mutual events of the Galilean satellites of Jupiter from the Vainu Bappu Observatory are presented in this paper, where the shifts in the photo-centers on the disks of Io and Europa due to albedo variations inferred from the available mosaics of Galileo imagery are determined.
Abstract: Astrometric results of CCD observations of the mutual events of the Galilean satellites of Jupiter from the Vainu Bappu Observatory are presented. The shifts in the photo-centers on the disks of Io and Europa due to albedo variations inferred from the available mosaics of Galileo imagery are determined. The estimated shifts from ≈ 90 km East to ≈ 50 km West on Io and from ≈ 50 km East to ≈ 30 km West for Europa during one orbital period are comparable to the accuracies provided by the present-day ephemerides. In a given mutual event series, the mutual events involving a given satellite pair dominate in number and occur nearly at the same orbital longitude within ± ; all the events are therefore delayed or all of them advanced depending on the direction of the shift of the photo-center. The implications of including these cumulative and sustained longitude residuals on the constructed ephemerides are discussed.

11 citations

Journal ArticleDOI
TL;DR: Results revealed that climate warming may potentially result in stronger outflow via the NEB than the MSB, and the linkage between the outflow with large scale atmospheric circulation patterns and climate warming trend over China was also discussed.
Abstract: Atmospheric outflow of alpha-HCH-HCH from China from 1952 to 2009 was investigated using Chinese Gridded Pesticide Emission and Residue Model (ChnGPERM). The model results show that the outflows via the northeast boundary (NEB, longitude 115-135 degrees E along 55 degrees N and latitude 37-55 degrees N along 135 degrees E) and the mid-south boundary (MSB, longitude 100-120 degrees E along 17 degrees N) of China account for 47% and 35% of the total outflow, respectively. Two climate indices based on the statistical association between the time series of modeled alpha-HCH outflow and atmospheric sea-level pressure were developed to predict the outflow on different time scales. The first index explains 70/83% and 10/46% of the intra-annual variability of the outflow via the NEB and MSB during the periods of 1952-1984 and 1985-2009, respectively. The second index explains 16% and 19% of the interannual and longer time scale variability in the outflow through the NEB during June-August and via the MSB during October December for 1991-2009, respectively. Results also revealed that climate warming may potentially result in stronger outflow via the NEB than the MSB. The linkage between the outflow with large scale atmospheric circulation patterns and climate warming trend over China was also discussed.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the location of the maximum meridional component of the anomalous 700 mb geostrophic wind (VgA) in the North Pacific on a monthly and seasonal time scale was investigated.
Abstract: An attempt was made to verify and further investigate a proposed relationship between the location of the maximum east-west sea surface temperature anomaly gradient (ΔSSTA) and the location of the maximum meridional component of the anomalous 700 mb geostrophic wind (VgA) in the North Pacific on a monthly and seasonal time scale. Previous empirical studies, mostly of a case study type, had suggested collocation of maximum values of these variables in the same time period, particularly during the cold seasons. Using 31 years of monthly sea surface temperature and 700 mb height data for the North Pacific, the two variables wore computed for each month and 3-month periods for each 10° longitude sector from 125°W to 155°E, and for each of three latitude bands (55–40°N, 40–25°N, 55–25°N). From these calculations, the spatial relationships of the two variables wore determined by counting frequencies of the collocation of maximum VgA and ΔSSTA for each month or season and latitude band, and by computing...

11 citations


Network Information
Related Topics (5)
Solar wind
26.1K papers, 780.2K citations
88% related
Planet
27K papers, 980.6K citations
82% related
Sea surface temperature
21.2K papers, 874.7K citations
80% related
Climate model
22.2K papers, 1.1M citations
79% related
Sea ice
24.3K papers, 876.6K citations
78% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023240
2022432
202142
202042
201960
201851