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| Titel |
Circulation changes in the winter lower atmosphere and long-lasting solar/geomagnetic activity |
| VerfasserIn |
J. Bochníček, H. Davídkovová, P. Hejda, R. Huth |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 30, no. 12 ; Nr. 30, no. 12 (2012-12-19), S.1719-1726 |
| Datensatznummer |
250017298
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| Publikation (Nr.) |
 copernicus.org/angeo-30-1719-2012.pdf |
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| Zusammenfassung |
| The paper describes the association between high long-lasting
solar/geomagnetic activity and geopotential height (GPH) changes in the
winter lower atmosphere, based on their development in the Northern
Hemisphere in the winter periods (December–March) of 1950–1969 and
1970–2002. Solar/geomagnetic activity is characterised by the 60-day mean of
the sunspot number R/by the 60-day mean of the daily sum of the Kp index.
The GPH distributions in the lower atmosphere are described by 60-day
anomalies from their long-term daily average at 20 hPa/850 hPa. The data
have been adopted from the NCEP/NCAR reanalysis. The 60-day mean values of
solar/geomagnetic activity and GPH anomalies were calculated in five-day
steps over the whole winter period. The analysis was carried out using
composite maps which represent their distribution of the GPH anomalies
during high solar activity (R ≥ 100) and high geomagnetic activity
(ΣKp ≥ 20). Analysis has shown that the distribution of GPH
anomalies depends on solar activity, geomagnetic activity and the phase of
winter period (early or late winter). The nature of this relationship then
depends on the time interval involved, i.e. 1950–1969 or 1970–2002. Positive
anomalies in the polar stratosphere (20 hPa) were detected during the whole
winter periods of the years 1950–1969. Significant anomalies were detected
in the lower troposphere (850 hPa) during the second half of the winter
period. The distribution of GPH anomalies on the maps compiled with regard
to solar activity was similar to the distribution on maps compiled with
regard to geomagnetic activity. In the interval 1970–2002, significant
negative GPH anomalies were detected in the stratosphere at high latitudes,
and positive anomalies were detected in the region of low latitudes. The
distribution of GPH anomalies in the lower troposphere was substantially
affected by situations in which, together with high solar activity, also
high geomagnetic activity occurred. |
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