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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 ArticleDOI
TL;DR: In this paper, the spatio-temporal characteristics of flare activity observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary Operational Environmental Satellite (GOES) satellites in connection with the behaviour of the longitudinal domain of enhanced sunspot activity known as active longitude (AL).
Abstract: The aim of the present work is to specify the spatio-temporal characteristics of flare activity observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary Operational Environmental Satellite (GOES) satellites in connection with the behaviour of the longitudinal domain of enhanced sunspot activity known as active longitude (AL). By using our method developed for this purpose, we identified the AL in every Carrington Rotation provided by the Debrecen Photoheliographic Data (DPD). The spatial probability of flare occurrence has been estimated depending on the longitudinal distance from AL in the northern and southern hemispheres separately. We have found that more than the 60\% of the RHESSI and GOES flares is located within $\pm 36^{\circ}$ from the active longitude. Hence, the most flare-productive active regions tend to be located in or close to the active longitudinal belt. This observed feature may allow predicting the geo-effective position of the domain of enhanced flaring probability. Furthermore, we studied the temporal properties of flare occurrence near the active longitude and several significant fluctuations were found. More precisely, the results of the method are the following fluctuations: $0.8$ years, $1.3$ years and $1.8$ years. These temporal and spatial properties of the solar flare occurrence within the active longitudinal belts could provide us enhanced solar flare forecasting opportunity.

11 citations

Journal ArticleDOI
TL;DR: The Global-scale Observation of Limb and Disk (GOLD) mission observed distinct post-sunset, hemispherically asymmetric evolution of the equatorial ionization anomaly between 40° and 50°W on 19 November 2018, with the southern crest shifting poleward but the northern crest remaining in the same latitude region as mentioned in this paper .
Abstract: The Global-scale Observation of Limb and Disk (GOLD) mission observed distinct post-sunset, hemispherically asymmetric evolution of the equatorial ionization anomaly between 40° and 50°W on 19 November 2018, with the southern crest shifting poleward but the northern crest remaining in the same latitude region. The Whole Atmosphere Community Climate Model-eXtended captured this phenomenon. Diagnostic analysis revealed that this asymmetric evolution was due to the hemispheric asymmetry in plasma transport by E × B drifts and neutral winds. In the Northern hemisphere, northward neutral wind transport dominated around sunset (20 UT near 45°W), causing the crest to be at lower altitudes and decay faster. After pre-reversal enhancement (PRE) occurred at 20 UT in the northern hemisphere, E × B and neutral wind transport largely balanced each other, and the crest remained in the same latitude region. In the southern hemisphere EIA crest, PRE occurred around 1 hr later than the one in the north. The northward neutral wind transported the plasma to higher altitudes with less recombination. E × B transport augmented the neutral wind transport after 21 UT, lifting and pushing the crest poleward. The magnetic field configuration (large declination) and the resultant occurrence time difference in PRE between 40°W and 50°W not only play critical roles in the asymmetric evolution of the two crests, but also makes it possible for this phenomenon to be observed in the GOLD field-of-view.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of the Macquarie Ridge earthquake on the earth's length of day, polar motion, and low-degree harmonic coefficients of the gravitational field are compared, and it is found that this earthquake should have caused the length-of-day to decrease by 0.06, the position of the mean rotation pole to shift 0.11 milliarcsec towards 323 E longitude, and selected degree l = 2-5 gravitational field coefficients to change by about 1 part in 10 to the 13th.
Abstract: The coseismic effect of the Macquarie Ridge earthquake on the earth's length-of-day, polar motion, and low-degree harmonic coefficients of the gravitational field are compared. It is found that this earthquake should have caused the length-of-day to decrease by 0.06, the position of the mean rotation pole to shift 0.11 milliarcsec towards 323 E longitude, and selected degree l = 2-5 gravitational field coefficients to change by about 1 part in 10 to the 13th.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the average latitude, longitude and central pressure of the four centers of action (Icelandic low, Aleutian low, Azores high, Pacific high) have been estimated for each of the 80 years of the Northern Hemisphere Historical Weather Map Series (1899-1978), and compared with year-average values of NHST and sea surface temperature (SST) in the region 0-10°S, 180-90°W of the equatorial eastern Pacific.
Abstract: The average latitude, longitude and central pressure of the four centers of action (Icelandic low, Aleutian low, Azores high, Pacific high) have been estimated for each of the 80 years of the Northern Hemisphere Historical Weather Map Series (1899–1978), and compared with year-average values of Northern Hemisphere surface temperature (NHST) and sea surface temperature (SST) in the region 0–10°S, 180–90°W of the equatorial eastern Pacific. Inasmuch as NHST and SST have been positively correlated during the 80-year period, their relations with the centers of action have been estimated using partial correlation coefficients. While there has been a tendency for northward displacement of all four centers of action at time of hemispheric warming, none of the partial correlations is significant at the 95% level, taking into account the serial correlation of the data. However, the correlation (r) of 0.31 in the case of the Aleutian low is on the verge of significance, and the correlation of 0.33 in the c...

11 citations

Journal ArticleDOI
TL;DR: In this article, a longitudinal fine structure in the distribution of foF2 in the night-time low-latitude ionosphere was found and analyzed for quiet geomagnetic conditions of all seasons at solar maximum.

11 citations


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