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.
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TL;DR: In this paper, the authors investigated the longitudinal variations of the nighttime E layer electron density in the auroral zone and their sources are discussed in terms of auroral precipitation and solar radiation, and the main conclusions are as follows:
Abstract: Longitudinal variations of the nighttime E layer electron density (21:00–03:00 magnetic local time) in the auroral zone are investigated, and their sources are discussed in terms of auroral precipitation and solar radiation. The electron density data used in this study are retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation observations during 2006–2009 under quiet geomagnetic activity (Kp ≤ 3) and solar minimum conditions. The main conclusions of this study are as follows: (1) the nighttime E layer electron density had pronounced longitudinal variations in the auroral zone. These variations depended on season and had large hemispheric asymmetry for all seasons. In winter, relatively larger electron density was located in 120–310° magnetic longitude (MLON) in the northern hemisphere and in 170–360° MLON in the southern hemisphere, and greater maximum density occurred in the northern hemisphere than in the southern one. In summer and equinox, the longitudinal asymmetry was greater in the southern hemisphere. (2) The peaks of the E layer electron density along latitude generally occurred between 65° and 70° magnetic latitude in the auroral zone in all seasons for both hemispheres except for the sunlit sector of the southern summer. (3) The greater electron density in local winter in the auroral zone was generally associated with the more intense auroral precipitation intensity at roughly the same longitude, whereas the longitudinal patterns of the electron density were under the combined impact of both auroral precipitation and solar radiation in the local summer and equinoxes.
12 citations
08 Aug 2019
TL;DR: In this paper, the intercomparison of wave hindcasts using the third-generation models WAM and WAVEWATCH-III for the North Indian Ocean over 1° × 1° (latitude × longitude) grid resolutions is presented.
Abstract: This paper presents the intercomparison of wave hindcasts using the third-generation models WAM and WAVEWATCH-III for the North Indian Ocean over 1° × 1° (latitude × longitude) grid resolutions, wh...
12 citations
TL;DR: This article examined characteristics of the seasonal variation of thermospheric composition using column number density ratio ∑O/N2 observed by the NASA Global Observations of Limb and Disk (GOLD) mission from low-mid to mid-high latitudes.
Abstract: We examine characteristics of the seasonal variation of thermospheric composition using column number density ratio ∑O/N2 observed by the NASA Global Observations of Limb and Disk (GOLD) mission from low-mid to mid-high latitudes. We also use ∑O/N2 derived from the Global Ultraviolet Imager (GUVI) limb measurements onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and estimated by the NRLMSISE-00 empirical model to aid our investigation. We found that the ∑O/N2 seasonal variation is hemispherically asymmetric: in the southern hemisphere, it exhibits the well-known annual and semiannual pattern, with highs near the equinoxes, and primary and secondary lows near the solstices. In the northern hemisphere, it is dominated by an annual variation, with a minor semiannual component with the highs shifting toward the wintertime. We also found that the durations of the December and June solstice seasons in terms of ∑O/N2 are highly variable with longitude. Our hypothesis is that ion-neutral collisional heating in the equatorial ionization anomaly region, ion drag, and auroral Joule heating play substantial roles in this longitudinal dependency. Finally, the rate of change in ∑O/N2 from one solstice season to the other is dependent on latitude, with more dramatic changes at higher latitudes.
12 citations
TL;DR: In this article, it was shown that the apparent differences, with longitude, of the surface/satellite ratios of the electrojet effects have been overestimated; they are within the margin of possible errors and other external factors have to be taken into account before calling for variable induced effects, in order to explain the longitude variation at satellite level.
12 citations
TL;DR: In this paper, the antifocal anomaly is adopted as the basis of a new orbital longitude, and a variation on the true-longitude method is obtained to numerically integrate perturbed Keplerian orbits.
Abstract: Adopting the antifocal anomaly as the basis of a new orbital longitude, we obtain a variation on the true-longitude method to numerically integrate perturbed Keplerian orbits. Although the new method is applicable to elliptical orbits only, it achieves a larger stability region and gives significantly smaller integration errors than the original method when the perturbations are small and the eccentricity is not too large.
12 citations