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.

Ionospheric response to 2009 sudden stratospheric warming in the Northern Hemisphere

Abstract: We study the behavior of the F region ionosphere in the Northern Hemisphere during the sudden stratospheric warming period of 19–30 January 2009 by using FORMOSAT-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) ionosphere data (NmF2, hmF2, and height profile). We concentrated our study in the longitude bands 30°E–30°W, as well as 150°E–150°W, where no detailed study has been reported so far. At low magnetic latitude, the NmF2 decreases except during 09–12 LT: in the latitude zone of 20–40° NmF2 shows an increase of 30% during 09–12 LT. At higher magnetic latitude the NmF2 shows an increase during daytime and a reduction in the evening (21–03 LT). There is a latitude zone where NmF2 does not change. The latitude seems to correspond to the latitude where atmospheric temperature does not change. The behavior of the NmF2 seems to suggest a reduction of neutral density in low latitude and increase of neutral density in higher latitude. During the period of day of year (DOY) 25–31, the NmF2 shows a drastic reduction only during 06–09 LT in low latitudes, which is slightly away from geomagnetic equator. This special feature which occurred during declining phase of the sudden stratospheric warming (SSW) might be explained as due to enhanced dynamo electric field. The study suggests global change of the thermosphere including dynamo region, in spite of the fact that SSW is a high-latitude phenomenon which occurred much below the height region of thermosphere.

Method and apparatus for acquiring position and orientation information

Abstract: PROBLEM TO BE SOLVED: To easily acquire information such as the latitude, the longitude or the like by a system of a low cost by installing latitude and longitude information or the like in a plurality of buildings, and reading the information of the latitude, the longitude or the like nearest to a present position. SOLUTION: Present position information is acquired by installing a plurality of position information display devices for installing latitude and longitude information at a plurality of buildings such as, for example, a pole 20 and reading the information by using a reader from the device nearest to the present position. That is, position information 30 installed on the pole 20 nearest a present place is confirmed. Since the information 30 is latitude and longitude information 340 stored in an IC tag, the information is inputted to a personal computer 10 by using an IC tag reader 150. As a result, a map and the present position are displayed on a display of the computer 10, and present position information can be easily acquired. COPYRIGHT: (C)2000,JPO

Mesoscale eddies northeast of the Hawaiian archipelago from satellite altimeter observations

Abstract: [1] Enhanced mesoscale eddy activity northeast of the Hawaiian archipelago was investigated by using the high-pass filtered satellite altimetric sea surface height (SSH) data of the past 16 years. The level of eddy kinetic energy (EKE) shows significant interannual variations, which appear well correlated to the large-scale atmospheric wind forcing associated with the Pacific Decadal Oscillation index; the EKE levels in the area along the Subtropical Front zone in 1997–1998 and 2003–2005, for example, were three times as large as those in the low EKE years. Spectral analyses in the 3° latitude by 5° longitude subregions revealed the dominant mesoscale periods ranging from 90 days near 18°N to 180 days near 36°N. A 3-layer quasi-geostrophic model constrained by World Ocean Atlas 2005 climatologies was used to explore instability of the regional circulation. The analysis shows a geographical match between baroclinic instability strength and the observed RMS SSH variability and a temporal match between seasonally varying instability strength and the observed seasonal EKE modulation, and suggests that baroclinic instability by the vertically sheared, regional mean circulation provides the energy source for the enhanced eddy variability northeast of the Hawaiian archipelago.