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.

Paleomagnetism of Late Cretaceous and Eocene limestones and chalks from Haiti: Tectonic interpretations

Abstract: We have conducted a paleomagnetic study of limestones and chalks from Haiti which suggests that the island of Hispaniola is a composite of at least two tectonically independent blocks. Sampling sites are distributed among three widely separated localities, namely: Les Cayes (nine sites; 18.3°N. Latitude; 73.6°W. Longitude) and Beloc (five sites; 18.4°N. Latitude; 72.6°W. Longitude) which are located on the southern peninsula of Haiti, and a northern locality, Ennery (six sites; 19.5°N. Latitude; 72.5°W. Longitude). Stable magnetization components of dual polarity and moderately high blocking temperature were revealed through progressive thermal demagnetization of samples from all of the Beloc and Ennery sites, while seven of the nine Les Cayes sites possessed unstable magnetizations. Mean paleolatitudes calculated from Beloc and Ennery data show 8° of latitudinal separation that is of at least Eocene age. Pole positions (Beloc: 43.2°N. Latitude; 185.8°E. Longitude, α95=25.1° and Ennery: 66.1°N. Latitude; 31.3°E. Longitude, α95=19.7°) show both colatitudinal and angular discordance with the North American apparent polar wander path. Based on these disparities, we demonstrate that the implied tectonic displacements tend to support some aspects of previously published Caribbean plate tectonic models.

Seasonal Changes of Oceanographic and Marine-Climatological Conditions in the Equatorial Atlantic.

Abstract: : An attempt is made to construct more detailed monthly charts for sea surface temperature, salinity, evaporation and precipitation, based on climatological averages for 2 degrees squares betweem 10N and 10 degrees S. This space and time resolution, at least, is required to study the complex climatological and mean oceanographic conditions, and their interrelationships, in an ocean area where significant local differences can occur at distances of a degree or two of longitude or latitude apart, and where semi-annual periodic changes may dominate the seasonal pattern. Of special interest are the relationships between sea surface salinity variations during the year and the differences between evaporation and precipitation. Special attention is given to seasonal variations of sea surface temperature anomalies, surface salinities and precipitation in the 5N to 10 degrees N latitudinal belt. This zonal belt is, essentially, dominated by the Equatorial Countercurrent.

The Behavior of Jet Streams over Eastern North America during January and February 1948

Abstract: A graph of the latitude of jet streams at 80° W longitude for a 49-day period in the winter of 1947–8 shows that the jet stream undergoes changes which appear as discontinuities on such a graph. Several cases are discussed which illustrate the manner in which these discontinuities appear. The new jets so formed then appear to experience a southward displacement before their disappearance. Accompanying the southward displacement at this longitude is a disappearance of the solenoidal field accompanying the jet in the lower troposphere, and an increase of the potential temperature in the center of the jet. DOI: 10.1111/j.2153-3490.1950.tb00320.x

A new perspective on the longitudinal variability of the semidiurnal tide

Abstract: The longitudinal variability of the semidiurnal tide in the Antarctic upper mesosphere is investigated by comparison of observations from two radars at approximately opposite sides of Antarctica. Under the assumption that the tide is composed of an S = 2 (migrating) and S = 1 (westward-propagating, non-migrating) component only, the relative phases of the components are shown to vary with season such that the waves are typically in constructive interference during the winter (summer) months at longitudes around 0 degrees E (180 degrees E). We show that this has profound effects on the seasonal behaviour of the semidiurnal tide around 78 degrees S dependent on the longitude, and that no single-station observations at this latitude can be considered representative of a "zonal mean". The superposition of these two waves is used to interpret differences in previously-published ground-based climatologies of the tide. Citation: Hibbins, R. E., O. J. Marsh, A. J. McDonald, and M. J. Jarvis (2010), A new perspective on the longitudinal variability of the semidiurnal tide, Geophys. Res. Lett., 37, L14804, doi:10.1029/2010GL044015.