Colaba–Alibag magnetic observatory and Nanabhoy Moos: the influence of one over the other

Gawali, Praveen B.; Doiphode, M. G.; Nimje, R. N.

doi:10.5194/hgss-6-107-2015

Cited by 6 publications

(5 citation statements)

References 16 publications

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“…One such place was the Colaba Magnetic Observatory. Established in colonial Bombay in 1841 by the East India Company (e.g., Gawali et al, ), the Colaba Observatory has long served as an important source of low‐latitude geomagnetic data. Its Superintendent from 1865 to 1896 was Charles Chambers (Unknown, ), who had previously worked at the Kew Observatory.…”

Section: Magnetic Disturbancementioning

confidence: 99%

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The Electric Storm of November 1882

Love

2018

Space Weather

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In November 1882, an intense magnetic storm related to a large sunspot group caused widespread interference to telegraph and telephone systems and provided spectacular and unusual auroral displays. The (ring current) storm time disturbance index for this storm reached maximum −Dst ≈ 386 nT, comparable to Halloween storm of 29–31 October 2003, but from 17 to 20 November the aa midlatitude geomagnetic disturbance index averaged 214.25 nT, the highest 4 day level of disturbance since the beginning of aa index in 1868. This storm contributed to scientists' understanding of the reality of solar‐terrestrial interaction. Past occurrences of magnetic storms, like that of November 1882, can inform modern evaluations of the deleterious effects that a magnetic superstorm might have on technological systems of importance to society.

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Section: Magnetic Disturbancementioning

confidence: 99%

“…Its Superintendent from 1865 to 1896 was Charles Chambers (Unknown, ), who had previously worked at the Kew Observatory. In 1870, a Kew‐pattern magnetograph was installed in Colaba, and automatic analog recording of geomagnetic variation began at Colaba in 1871 (e.g., Gawali et al, ).…”

Section: Magnetic Disturbancementioning

confidence: 99%

The Electric Storm of November 1882

Love

2018

Space Weather

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“…By 1859, many of these observatories were operating, although most magnetic instruments recording went off-scale during the most disturbed period of the storms. A notable exception of this was the magnetic observatory at Colaba, India (Gawali et al, 2015), which did not go off-scale (Kumar et al, 2015;Tsurutani et al, 2003). In addition, with the exception of observations in Kew and Greenwich, observations at the time were taken manually.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Field Measurements From Rome During the August–September 1859 Storms

et al. 2020

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The geomagnetic storm (or "Carrington event") of 1-2 September 1859 is one of the largest geomagnetic disturbances on record. At the time, it caused widespread disruption to telegraph systems and was accompanied by aurorae seen overhead as far south as ∼29 • magnetic latitude. The magnitude of the Carrington event means it remains a popular subject of study in the field of space weather, despite the sparse magnetic measurements available from the time. One set of measurements that is available is from the Rome observatory ("Collegio Romano," magnetic latitude ∼38.6 • ). Here we transcribe these horizontal magnetic field data and convert them to nanoteslas. We find that the device used at Rome had an operational range of around 305 nT. Despite going off-scale during the storm, the magnetometer at Rome recorded changes of hundreds of nanoteslas per minute and tens of nanoteslas per second in the horizontal magnetic field. Apart from the tabulated data, we also examine the reported off-scale deviation of 3,000 nT at Rome during the storm. While we could not explicitly locate this reported deviation in the tabulated data, we find that this deviation is comparable to magnetic variations seen at auroral latitudes for modern large magnetic storms, indicating that Rome was in the auroral oval during the morning of 2 September 1859. By comparing this large off-scale deviation to modern geomagnetic data, we estimate that Rome may have experienced a maximum change of 420 nT min −1 .Geomagnetic storms can be characterized by the disturbance storm-time index (Dst), a proxy for the energy in the ring current during a storm (Gonzalez et al., 1994). This value is calculated as an hourly average of four

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“…Its Superintendent from 1865 to 1896 was Charles Chambers (Unknown, 1896), who had previously worked at the Kew Observatory. In 1870, a Kewpattern magnetograph was installed in Colaba, and automatic analog recording of geomagnetic variation began at Colaba in 1871 (e.g., Gawali et al, 2015). (Baranyi et al, 2016).…”

Section: Magnetic Disturbancementioning

confidence: 99%

“…What was not understood, at the close of the nineteenth century, was what this "binding connection" could be (e.g., Cliver, 1994;Good, 1988;Serviss, 1883). Theories were proposed, including "corpuscular" theories that resemble modern understanding of the solar wind (e.g., Fitzgerald, 1892), but when the (influential) Lord Kelvin (1893) calculated that magnetic waves emanating more or less uniformly from the Sun were unlikely to be of sufficient strength to cause magnetic storms at the Earth, some wondered whether or not the correlation between sunspots and magnetic storms might just be a "coincidence." The subject was further complicated by Airy's conclusion that at least part of the magnetic disturbance measured at observatories was due to the Earth currents that were affecting telegraph systems (Airy, 1868).…”

Section: Solar-terrestrial Interactionmentioning

confidence: 99%