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.

Longitude distribution of solar flares

Abstract: Statistical tests of solar flares based on maximum likelihood method, discussing longitude distribution, rigid rotation, planetary effects, etc

Analysis of selected nitric oxide observations in the lower thermosphere by HALOE on UARS

Abstract: Measurements of nitric oxide mixing ratios have been made by the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite over an altitude range extending from 15 to 130 km on every spacecraft sunrise and sunset event with the exception of about 8 percent downtime. Selected NO profiles from the first few months of observations were examined with emphasis on the relation between geomagnetic disturbances and enhanced NO in the lower thermosphere. During a large geomagnetic storm on November 8-9, 1991, HALOE obtained 15 NO sunrise profiles along about the 50 deg N latitude circle. A factor of three increase in NO mixing ratio above about 115 km at this latitude and a one to two day decay time were observed. The measured NO longitude/altitude cross section on this day shows a longitudinal asymmetry in the NO distribution with a maximum near the geomagnetic pole. From approximately one month's data, a latitude/altitude cross section of zonal mean NO mixing ratio was calculated. An example of such cross sections demonstrates a strong positive correlation between geomagnetic activity and thermospheric NO globally. This auroral forcing has a larger effect on increasing NO at high latitude than at low latitude.

Communications/Navigation Outage Forecasting System observational support for the equatorial E × B drift velocities associated with the four-cell tidal structures

Abstract: [1] Previous studies have established the existence of a four-cell longitude pattern in equatorial F region ionospheric parameters such as total electron content and electron densities and in daytime, equatorial E × B drift velocities This paper, for the first time, quantifies the longitude gradients in E × B drift associated with the four-cell tidal structures and confirms that these sharp gradients exist on a day-to-day basis For this purpose, we use the Ion Velocity Meter (IVM) sensor on the Communications/Navigation Outage Forecasting System (C/NOFS) satellite to obtain the daytime, vertical E × B drift velocities at the magnetic equator as a function of longitude, local time, and season The IVM sensor measures the E × B drift velocity in three dimensions; however, we only use the E × B drift observations perpendicular to B in the meridional plane These observations can be used to obtain the vertical E × B drifts at the magnetic equator by mapping along the geomagnetic field line The period initially selected for this work covers several days in October, March, and December 2009 We find, on a day-to-day basis, that (1) sharp E × B drift gradients of −13 m s−1 deg−1 exist in the western Pacific sector during equinox, (2) sharp E × B drift gradients of +3 m s−1 deg−1 are observed in the eastern Pacific sector during equinox, and (3) sharp E × B drift gradients of −17 m s−1 deg−1 exist in the eastern Pacific sector during December solstice

The Rhine River basin

Abstract: The British Isles, comprising the United Kingdom (Scotland, England, Wales, and Northern Ireland) and the Republic of Ireland, lies at the northwest Atlantic seaboard of Europe. The latitude and longitude ranges from around 50°N to 61°N and 2°E to 11°W. As the landmasses of mainland Britain and the island of Ireland are small, the sea is always close, and the rivers are small in comparison with continental Europe. Despite this, the area has marked differences in climate, geology, and population densities that result in a diverse range of rivers with distinctive physical, chemical, and ecological characteristics and varying degrees of human impact.