Geomagnetic
Rapid variations
INTERNATIONAL SERVICE ON RAPID MAGNETIC VARIATIONS
Since 1975, Ebre Observatory houses the International Service on Rapid Magnetic Variations, responsible for creating and publishing the lists of rapid variations. This task was entrusted by the International Association of Geomagnetism and Aeronomy (IAGA), and is part of the International Service of Geomagnetic Indices (ISGI).
The geomagnetic field presents all kinds of variations. Some are smooth and periodic, like the daily variation, whereas others present the shape of sudden variations, like SSC (Sudden Storm Commencements) and SFE (Solar Flare Effects).
The following are the final annual lists of rapid variations than can be found in the IAGA bulletins.
SSC Tables
The given tables of data correspond to different series. The first corresponds to the period 1868-1967, the second to the period 1968-1994, the third to the period 1995-2005, and the last one to the period beginning the year 2006. In all of them qualification codes are given of the SSC records of low latitude observatories selected by IAGA for the determination of the data of the SSC. The codes have practically the same meaning in all series, which is the following one:
3 or 2: the event can be unmistakably identified as being an SSC from the single record under consideration. Number 3 is imposed instead of 2 when the following three features are present: a) very sharp change of rhythm, b) large amplitude of the sudden movement, c) remarkably morphology of it.
1: means that the event seen in this particular record is possibly an SSC, but it is not sufficiently clear by itself for stating that it is a true SSC: One need records from other longitudes for getting a firm judgement
0: means that the event, such as it appears in the record, could escape from the attention of the observer, or does not deserve to be called an SSC. From 2006 it can mean that some characteristic defining the SC, fails
Tables for the period 1868-1967
Data of the 100 first years (1868-1967) have been obtained by P.N. Mayaud from three collections of records that he calls: N (mainly containing records of Saint-Maur, Val-Joyeux and Chambon-la Foret), S (fundamentally with records of Melbourne y Toolangi) and T (with records of Colaba y Alibag fundamentally, including records of Batavia-Buitenzorg-Kuyper-Tangerang from1880).
For every SSC the tables contain the date (DATE), the time (HH:MM), the qualification codes corresponding to each collection N, T and S (CODE), the SSC duration (DURATION), its amplitude in the records of collection T (AT), and the normalized amplitude of one of the other two collections or the normalized mean of both (ANS). (cf. IAGA Bulletin No. 33)
Tables for the period 1968-1994
The data are obtained from the records of the five low latitude observatories: MBO, FUQ, HON, PMG and ABG. When the record of some of these observatories is missing the record of the corresponding supplementary observatory is used. The supplementary observatories are GUI, SJG, API, KNY and HYB respectively.
For every SSC the tables contain the date, the time, the qualification codes of the records of the five observatories, the SSC duration, its amplitude, the qualification codes given by the collaborating observatories of their records, and the number of observatories that qualify the event as Si or sfe. The SSC time, duration and amplitude are the mean values obtained from the records of the five low latitude observatories. The Qualification codes used by the collaborating observatories have the following correspondence with the codes defined above: A corresponds to 3, B to 2 and C to 1. A hyphen indicates that no code has been given.
From 1992 a new column is added with the SSC extreme time values given by the collaborating observatories.
Tables for the period 1995-2005
The column with the qualifying codes given by the collaborating observatories has been omitted. The list of the collaborating observatories has been added before the tables. The penultimate column indicates the qualification of the events in the records of the five low latitude observatories reported in the last column.
| SSC | SFE |
|---|---|
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Final data:
1868,
1869,
1870,
1871,
1872,
1873,
1874,
1875,
1876,
1877,
1878,
1879,
1880,
1881,
1882,
1883,
1884,
1885,
1886,
1887,
1888,
1889,
1890,
1891,
1892,
1893,
1894,
1895,
1896,
1897,
1898,
1899,
1900,
1901,
1902,
1903,
1904,
1905,
1906,
1907,
1908,
1909,
1910,
1911,
1912,
1913,
1914,
1915,
1916,
1917,
1918,
1919,
1920,
1921,
1922,
1923,
1924,
1925,
1926,
1927,
1928,
1929,
1930,
1931,
1932,
1933,
1934,
1935,
1936,
1937,
1938,
1939,
1940,
1941,
1942,
1943,
1944,
1945,
1946,
1947,
1948,
1949,
1950,
1951,
1952,
1953,
1954,
1955,
1956,
1957,
1958,
1959,
1960,
1961,
1962,
1963,
1964,
1965,
1966,
1967,
1968,
1969,
1970,
1971,
1972,
1973,
1974,
1975.
1976,
1977,
1978,
1979,
1980,
1981,
1982,
1983,
1984,
1985,
1986,
1987,
1988,
1989,
1990,
1991,
1992,
1993,
1994
1995,
1996,
1997,
1998,
1999,
2000,
2001,
2002,
2003,
2004,
2005
Refined Preliminary Data:
Preliminary data:
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Final data:
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