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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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Journal Article
TL;DR: A 1961-90 mean monthly climatology for Africa south of the Equator was constructed for a suite of eight surface climate variables and fields of mean monthly potential evapotranspiration (PET) for the region are constructed using a number of different calculation methods.
Abstract: A 1961-90 mean monthly climatology for Africa south of the Equator was constructed at a resolution of 0.5° latitude/longitude for a suite of eight surface climate variables: minimum, maximum and mean air temperature; rainfall; sunshine hours; vapour pressure; wind speed; and rain day (>0.1 mm)frequencies. This climatology was constructed from observed station data distributed across the region with station frequencies ranging from 288 (wind speed) to 916 (rainfall). Over 92% of these data is based on observations between 1961-90 and over 85% has been supplied by national meteorological agencies from the region. Additionally, for mean temperature and rainfall, monthly anomalies with respect to the 1961-90 average have been calculated at the same spatial resolution for each month from January 1961 to December 1994. This paper describes the dataset which has been compiled for this work, the interpolation methods which have been used, together with some assessment of the accuracy of the resulting climate surfaces. The interpolation of the 1961-90 normals uses elevation, as well as longitude and latitude, as predictor variables and this enables three climate surfaces to be constructed for each variable, reflecting the 'minimum', mean and 'maximum' elevation within each 0.5° cell. The interpolation of the anomaly fields uses a simpler method in which elevation is not considered. These anomaly time series enable fields of interannual variability to be established for mean temperature and rainfall. The second part of the paper uses this climatology to construct fields of mean monthly potential evapotranspiration (PET) for the region using a number of different calculation methods. A comparison of the resulting PET estimates highlights significant spatial and seasonal biases due to differences in climate input variables and in the theoretical representation of PET. The climatology, described and analysed here is available from the authors for use in climate modelling and the study of climate change in Africa south of the Equator.

28 citations

Journal ArticleDOI
TL;DR: In this paper, the solar eruption of October 1, 1937, was investigated and the results showed that the solar eruptions occurred in an area around 30° 19′.1 S, longitude 115° 52′.6 or 7h 43m.5 E.
Abstract: (Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.) October 1—See “Note on solar eruption of October 1, 1937” under Letters to Editor in this issue.

28 citations

Journal ArticleDOI
TL;DR: In this article, the occurrence frequency of 150 km (or F1) echoes has a broad but conspicuous maximum during northern summer in this longitude sector with minimal activity in other months.
Abstract: [1] Using three and a half years of 50 MHz radar data collected from Pohnpei, Federated States of Micronesia (6.96°N, 158.19°E geographic, 0.3° magnetic dip latitude), we show for the first time that the occurrence frequency of 150 km (or F1) echoes has a broad but conspicuous maximum during northern summer in this longitude sector with minimal activity in other months. Given a seasonal similarity to sporadic E (Es), we suggest that an Es-layer instability [Cosgrove and Tsunoda, 2002] generates a polarization electric field (), which maps along geomagnetic field lines to the F1 region. There, forms thin plasma sheets that provide gradients to excite 3-m-scale plasma waves via an interchange process.

28 citations

Journal ArticleDOI
TL;DR: In this paper, the relationship between heliographic longitude and the delay between flare occurrence and solar proton observation was studied using results obtained aboard HEOS A1 during 1969, and the authors ascribe this to the formation of a long-lived magnetic field configuration close to the Sun associated with a particular group of active regions.
Abstract: The relationship between heliographic longitude and the delay between flare occurrence and solar proton observation is studied using results obtained aboard HEOS A1 during 1969. The result obtained differs from previous findings. We ascribe this to the formation of a long-lived magnetic field configuration close to the Sun associated with a particular group of active regions.

28 citations

Journal ArticleDOI
24 Dec 1971-Science
TL;DR: Radar observations of a narrow belt of the surface of Mars, centered at 16�south latitude, show a very rugged terrain, with elevation differences greater than 13 kilometers from peak to valley.
Abstract: Radar observations of a narrow belt of the surface of Mars, centered at 16 deg south latitude, show a very rugged terrain, with elevation differences greater than 13 kilometers from peak to valley. For nearby points, the relative altitude is measured to 40 meters at best; the precision is worse for points at different latitudes, or widely separated in longitude, because of orbital uncertainties. Some of the larger craters have been resolved, and their depth and, in some cases, the height of the raised rim have been measured. Where high resolution photographs are available, the correlation is excellent.

28 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023240
2022432
202142
202042
201960
201851