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.

Climatology of equatorial and low-latitude F region kilometer-scale irregularities over the meridian circle around 120°E/60°W

Abstract: The occurrences of equatorial plasma bubble (EPB) irregularities over Asian and American sectors often show a different behavior due to significantly different geometries of the geomagnetic field. By using the GPS total electron content observations over equatorial and low latitudes sectors of Asian (about 120°E) and American (about 60°W) during 1997–2018, we present a comparative study of long-term occurrences of EPB kilometer-scale irregularities over the two longitude sectors. The results show that post-sunset EPB irregularities over the Asian sector were positively correlated with solar activity. However, in the American sector, such a positive dependence was not apparent in 2000–2002, which could be partly induced by limited data available during the high occurrence season of solar maximum when the GPS receivers frequently lost lock. The geomagnetic disturbance tends to inhibit the generation of EPB irregularities over both sectors during post-sunset but enhance their generation during post-midnight. The latitudinal distribution of EPB irregularities exhibited a double-peak structure centered within ± 10° (dip lat.), with the latitudinal limit below ± 25° at solar maximum in both sectors and below ± 20° and ± 10° at solar minimum in American and Asian sectors, respectively. Specifically, in the American sector, the occurrence rates were about two times higher than those in the Asian sector, and the occurrence rates in the northern hemisphere were apparently lower than those in the southern hemisphere. The enhanced ionization by particle precipitation over the South Atlantic Magnetic Anomaly region could cause the north–south asymmetry of occurrence rates of EPB irregularities. The results help in designing experiments to understand better the generation of EPB irregularities under the future international meridian circle project.

Satellite Observations of Ocean Long Waves in the Eastern Equatorial Pacific, 1981-1983

Abstract: Satellite (NOAA-7) multi-channel sea surface temperature charts are prepared at weekly intervals with a spatial resolution of 50 km in the Eastern Equatorial Pacific between October 1981 and November 1983. The start and end of the 1982- 1983 El Nino event is evident in sea surface temperature time series at the equator. Westward propagating equatorial long waves appear during 1981 and 1983, but are absent during 1982. During 1983 there is a pronounced westward penetration of the long waves to longitude 160W while in 1981 the waves are confined to longitude 130W.

Global annual snow accumulation by months

Abstract: : The compilation of observed mean monthly snow accumulations for the globe was taken from a variety of climatological sources and formats. They were reformatted to fit the global 4 latitude by 5 longitude grid of the RAND coupled two-level oceanic and two-level atmospheric general circulation model (GCM). The results are presented in the form of machine-analyzed isopleths on global maps, global grid-point tabulations, and global means. These products were used at RAND to initialize GCM calculations, to facilitate comparisons with global integrations from the GCM, and as the global climatological summary. The snow- accumulation data given here were derived from observed data from various sources, presented in a variety of formats. Most of the monthly measurements were from scheduled snow-depth observations made in the Northern Hemisphere that were published before 1976. These data were gathered and developed into monthly climatologies, expressing conditions representative of the last day of each month, by the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL). To supplement the CRREL summaries, a pseudoclimatology of monthly snow accumulations was developed at RAND for the 4 latitude by 5 longitude grid points through the data-sparse areas of China, Greenland, the Arctic basin, and the Antarctic. (sdw)

Traffic condition management method and system

Abstract: The invention discloses a method and a system for managing traffic condition. The method is characterized in that a traffic road network file containing a detailed data area and a logic grid area is established in advance, wherein, serial numbers of all roads within a designated area and corresponding traffic condition are stored in the detailed data area; the designated area is divided into grids which are equal in size and correspond to various latitude and longitude ranges; and latitudes, longitudes and serial numbers of all roads within each grid are stored in the logic grid area. The method comprises the following steps: according to the latitude and the longitude of a road to be located, a grid in which the road to be located is positioned can be located in the logic grid area; according to the latitude and the longitude of the road to be located, the serial number of a road matched with the road to be located can be found within the located grid; and according to the found serial number, traffic condition corresponding to the road is sought in the detailed data area. The scheme provided by the invention improves the efficiency of seeking traffic condition.

Geosat altimeter observations of long waves in the equatorial Atlantic

Abstract: Geosat altimeter observations covering most of the equatorial Atlantic between March and November 1987 were examined Six ground tracks were selected with equator crossings between 15°W and 23°W longitude At these locations there is evidence of westward propagating long waves during four repeat passes between July and October Best fit parameters are phase velocity of 45 ± 6 cm s−1 and period of 25 ± 2 days Waves are likely present over a wider range in longitude, but the observations are restricted by scan lines intersecting Africa to the east and noise associated with geoid undulations near the mid-Atlantic ridge to the west A composite mean wave pattern was constructed between 8°N and 8°S latitude The pattern resembles a somewhat distorted free mode There are two off-equatorial maxima of 33 ± 10 cm near 4°N and 26 ± 07 cm near 4°S latitude The northern maxima has a distinct NW-SE tilt of about 30° This is direct evidence of the transport of energy from the mean zonal flow into the wave The kinetic energy replacement time is about 17 days For comparison, an example of a shear instability wave in a simple rotating system is shown with the same sort of tilt as well as a free mode without a tilt