scholarly journals Some features of magnetic elements at Trivandrum and Annamalainagar, situated near the geomagnetic equator in the Indian Peninsula

MAUSAM ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 377-392
Author(s):  
A. YACOB
Keyword(s):  
Diurnal Variation ◽  
Numerical Magnitude ◽  
Geomagnetic Equator ◽  
Smooth Curves ◽  
Indian Peninsula ◽  
Longitudinal Plane ◽  
Day Range ◽  
Magnetic Elements ◽  
Quiet Day ◽  
Disturbance Field

The Sq diurnal variation in H at Trivandrum and Annamalainagar are found to be large compared with those at Alibag. The quiet day range in H at Trivandrum in the month of March is abnormally large. Though the Sq variations in V at Trivandrum are not abnormal they are larger than those at Annamalainagar and Alibag. The response of the H elements to disturbance at Trivandrum, Annamalainagar as well as Alibag are similar in sense. But the V element at Annamalainagar shows a difference in its response to disturbance. When the V elements at both Alibag and Trivandrum show an increase in numerical magnitude the V element at Annamalainagar shows a decrease and vice versa. When the magnitudes of disturbance are examined they are found to be almost the same in the H element at all the observatories (including Alibag) during night hours. But during the day the magnitudes of disturbance in H element at Trivandrum and Annamalainagar are always greater than that at Alibag, a station away from the geomagnetic equator. Effects of disturbance in the V element are greatest at Trivandrum both during the day as well as the night. The lines of force of an average disturbance field in a longitudinal plane over the region of the Indian Peninsula appear to be smooth curves with their concave side turned upwards, their turning points occurring between Annamalainagar and Alibag during the day and close to Alibag in the night.

scholarly journals I. On the evidence of the existence of the decennial inequality in the solar-diurnal magnetic variations, and its non-existence in the lunar-diurnal variation, of the declination at Hobarton

1857 ◽  
Vol 147 ◽  
pp. 1-8 ◽  
Keyword(s):  
Diurnal Variation ◽  
Royal Society ◽  
Magnetic Elements ◽  
Imperial Academy ◽  
The Subject ◽  
British Colonial ◽  
The Mean ◽  
Hourly Observation ◽  
Academy Of Sciences ◽  
Magnetic Observatories

In a report presented to the British Association at Liverpool in September 1854, entitled "On some of the results obtained at the British Colonial Magnetic Observatories," I stated that, as far as my examination of the observations had then gone, I had found in the Lunar-diurnal magnetic variation no trace of the decennial period which is so distinctly marked in all the variations connected with the Sun. And in a subsequent communication to the Royal Society in June 1856, “On the Lunar-diurnal Variation at Toronto,” in which the moon’s influence on each of the three magnetic elements was examined, the conclusion arrived at was to the same effect, viz. that the observations at Toronto “showed no appearance of the decennial period which constitutes so marked a feature in the solar-diurnal variations.” Since these statements were made, I have read M. Kreil’s memoir “On the Influence of the Moon on the horizontal component of the Magnetic Force,” presented to the Imperial Academy of Sciences at Vienna in 1852 and printed in 1853, from which I learn (pp. 45, 46) that M. Kreil is of opinion that the observations of different years at Milan and Prague, when combined, would rather favour the supposition that the same decennial period which exists in the solar variation affects also the lunar magnetic influence. The question is one of such manifest importance in its theoretical bearing, that I considered it desirable to lose no time in re-examining it by the aid of the Hobarton observations, which, as it appeared to me, were particularly suitable for the purpose, inasmuch as they consist of eight consecutive years of hourly observation (from January 1841 to December 1848 inclusive), made with one and the same set of instruments, and by a uniform system of observation. The results of this examination have been, as it appears to me, so decidedly confirmatory of the conclusions drawn from the Toronto observations, both as regards the existence of the decennial period in the two classes of solar-diurnal variation (viz. in the mean diurnal variation occasioned by the disturbances of large amount, and in what may be termed the more regular solar-diurnal variation), and the non-existence of a similar decennial period in the case of the lunar-diurnal variation, that I have been induced to make these results the subject of a communication to the Royal Society.

scholarly journals XIX. Results of the magnetic observations at the Kew Observatory.— No. III

1866 ◽  
Vol 156 ◽  
pp. 441-451
Keyword(s):  
Diurnal Variation ◽  
Present Communication ◽  
Terrestrial Magnetism ◽  
Magnetic Elements ◽  
Rigorous Description ◽  
Magnetic Investigation ◽  
Magnetic Observatories ◽  
At Home

T h e recognition of a cosmical origin of some of the variations of terrestrial magnetism has made it desirable to employ in magnetic observatories apparatus of a more exact and dependable character, and methods of dealing with the results thus obtained of a more close and rigorous description, than were previously thought requisite. The present communication is directed to the discussion of the Lunar-diurnal Variation of the three magnetic elements shown by the instrum ents and methods adopted at the Kew Observatory, commencing in 1858, and continued as far as the reductions have at present proceeded, viz. to the close of 1864. I t has the double purpose, first, of making known the systematic and highly satisfactory character of the results which have been already obtained; and, second, of acting in some measure as a guide, and certainly as an encouragement, to the several establishments at home and abroad which have adopted the Kew System of magnetic investigation.

scholarly journals On the variability of the quiet-day diurnal magnetic variation at Eskdalemuir and Greenwich

1929 ◽  
Vol 123 (791) ◽  
pp. 27-53 ◽  
Keyword(s):  
Annual Variation ◽  
Daily Variation ◽  
Sunspot Cycle ◽  
Ultra Violet ◽  
Cyclic Change ◽  
Ultra Violet Radiation ◽  
Magnetic Elements ◽  
Magnetic Variation ◽  
Quiet Day ◽  
Violet Radiation

§ 1. The solar diurnal magnetic variation on quiet days (conveniently denoted by S q ) undergoes more or less regular changes of two kinds: one, affecting both type and amplitude, in the course of each year—an annual variation; the other, affecting chiefly the amplitude, in the course of the sunspot cycle—this will be termed the solar-cyclic change. In addition, it undergoes irregular or fortuitous changes from day to day. These have scarcely been studied as yet, and there is no precise systematic information available concerning them. They are of considerable interest owing to their probable connection with day-to-day changes in the sun’s ultra-violet radiation. We therefore propose to examine them systematically, especially with reference to their similarity at different stations. In this paper we confine ourselves to the records for Eskdalemuir and Greenwich, the respective geographical co-ordinates being:— Latitudr. Longitude. ˚ ' ˚ ' Eskdalemuir . . . . . . . . . . . . 55 19 N 3 12W Greenwich . . . . . . . . . . . . . 51 28 N 0 0 The material used consists of the daily ranges, in all three magnetic elements, on 819 very quiet days. It is shown that the ranges suffice for the comparison of different days, since (§ 15) the irregular changes in S q , at any particular season and solar epoch, affect almost solely the amplitude of the daily variation, while the type, that is, the form of the curves representing the diurnal inequalities, remains constant.

GEOMAGNETIC MICROPULSATIONS IN THE AURORAL ZONES

1965 ◽  
Vol 43 (7) ◽  
pp. 1373-1387 ◽  
Author(s):  
C. S. Wright ◽  
J. E. Lokken
Keyword(s):  
Diurnal Variation ◽  
Conjugate Point ◽  
Small Time ◽  
Ionospheric Absorption ◽  
Magnetic Elements ◽  
The Hours ◽  
Sudden Commencements ◽  
The Times ◽  
Maximum Occurrence ◽  
Adequate Data

This report deals with micropulsation data measured at Fort Churchill and at the near-conjugate stations of Byrd and Great Whale River during the conjugate-point experiment by Stanford University and Pacific Naval Laboratory. All three stations are in the auroral zones; and the data, though discontinuous, cover the period from 1961 to 1963.On the assumption that near-coincidence in time of events should be displayed at two conjugates, attention has been concentrated on the times of occurrence of the relatively numerous polar sudden commencements which often introduce the negative bays. There is a striking and very persistent diurnal variation, with maximum occurrence in the hours 03 to 04 G.M.T., which shows at all three stations, but most clearly at the two conjugates.A small time difference, of about one minute on the average, is apparent between events measured at Byrd and those at Great Whale. There is a tendency for the events to be preceded by a quiet period, and they correspond to sudden changes shown on local magnetograms, and lead to a similar diurnal variation of the magnetic elements H, D, and V. A similar pattern appears in the sudden changes of ionospheric absorption shown on the riometer records from Cape Jones, which is about 180 km from Great Whale Rive; but adequate data for individual time differences are lacking. The coincidence of nighttime active auroras and micropulsation polar-storm commencements measured at the same station seems to be very close. The quiet daytime auroras often show coincident pulsations of light intensity of the same period as the regular (Pc type) micropulsations.

Diurnal variation of the tropospheric water vapour over a coastal and an inland station in Southern Indian Peninsula

2018 ◽  
Vol 179 ◽  
pp. 11-21 ◽  
Author(s):  
Maria Emmanuel ◽  
S.V. Sunilkumar ◽  
M. Venkat Ratnam ◽  
M. Muhsin ◽  
K. Parameswaran ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Water Vapour ◽  
Indian Peninsula

scholarly journals On the variability of the quiet-day diurnal magnetic variation. Part II

1931 ◽  
Vol 130 (815) ◽  
pp. 668-697 ◽  
Keyword(s):  
Magnetic Axis ◽  
Vertical Force ◽  
Horizontal Force ◽  
Mean Values ◽  
Magnetic Latitude ◽  
Magnetic Elements ◽  
Geographical Latitude ◽  
Magnetic Variation ◽  
Quiet Day ◽  
Variation Part

This paper is a sequel to our former one relating to the daily magnetic variation, on really quiet days, at Eskdalemuir and Greenwich. Here we extend the investigation to four more magnetic observations; the principal relevant particulars for the whole six observatories are as follows:— The last three columns give approximate mean values of the three magnetic elements, H (horizontal force), Z (downward vertical force) and declination. The stations range over 75° of geographical latitude, and 85° of magnetic latitude ( i. e ., latitude with respect to the earth's magnetic axis).

scholarly journals II. On the simultaneity of magnetic variations at different places on occasions of magnetic disturbance, and on the relation between magnetic and earth current phenomena

1892 ◽  
Vol 51 (308-314) ◽  
pp. 445-446 ◽  
Keyword(s):  
Diurnal Variation ◽  
Magnetic Storms ◽  
Magnetic Disturbance ◽  
Progressive Change ◽  
Magnetic Elements ◽  
Sun Spots ◽  
Magnetic Disturbances

In this paper the author refers to the ordinary variations of the magnetic elements as observed at Greenwich; the annual progressive change; the diurnal variation—large in summer, small in winter, and also larger when sun spots are numerous and smaller when sun spots are few; the irregular magnetic disturbances and magnetic storms, and the accompanying earth currents; phenomena which are generally similar at other places.

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