 |
| Titel |
Colaba–Alibag magnetic observatory and Nanabhoy Moos: the influence of one over the other |
| VerfasserIn |
P. B. Gawali, M. G. Doiphode, R. N. Nimje |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
2190-5010
|
| Digitales Dokument |
URL |
| Erschienen |
In: History of Geo- and Space Sciences ; 6, no. 2 ; Nr. 6, no. 2 (2015-09-16), S.107-131 |
| Datensatznummer |
250115494
|
| Publikation (Nr.) |
 copernicus.org/hgss-6-107-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| The first permanent magnetic observatories in colonial India were established
by the East India Company and under the Göttingen Magnetic Union. One of
the world's longest running observatories was set up at Colaba (Bombay) in
1841, which was shifted to Alibag in 1904 to avoid electric traction effects
on magnetic recordings. The observatory is located at the northwestern tip of
Maharashtra, India, on the Arabian Sea. The magnetic data at Colaba were
collected through eye-observation instruments from 1841 to 1872 and by
photographic (magnetograph) instruments from 1872 to 1905, which reveal
seasonal and other periodic effects on geomagnetic elements. Seasonal
influence can be deciphered on the H minimum, but not on the maximum; the
disturbances in March and April were opposite to those in December and
January. D was maximum in 1880 (57' E) and minimum in 1904 (10' E).
The data from 1882 to 1905 revealed that H annual inequality was influenced
by 5.5-year periodicity, D by 13.5 days from 1888 to 1905, and I and Z
by 11-year periodicity from 1894 to 1905 and 1873 to 1905, respectively.
Secular variation of Z was parallel to that of I. Z exhibited an
increasing trend from 1868 (12 874 nT) to 1905 (15 083 nT). The plan and
location of Colaba–Alibag as well as the instruments used are discussed. The
initial Colaba magnetic data containing "magnetic disturbances" was
harnessed to identify the "disturbing point" on Earth. Nanabhoy Moos, the
first Indian director, presciently hinted at a solar origin for magnetic
disturbances, revealed the dependence of magnetic elements on the sunspot
cycle, unraveled disturbance daily variation, and tried to understand the
association, if any, between geomagnetic, seismological and meteorological
phenomena. The two giant volumes published in 1910 attest to Moos' seminal
work and his inventiveness in organizing and analyzing long series data. He
also had a major role in moving Colaba magnetic observatory to Alibag. Thus,
the observatory and Moos had a synergestic relationship influencing each
other. The long data series has as much historical significance as
scientific, which can bring out short- as well as long-term trends in
geomagnetic data. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|