Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 30, 1719-1726, 2012
https://doi.org/10.5194/angeo-30-1719-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
Regular paper
19 Dec 2012
Circulation changes in the winter lower atmosphere and long-lasting solar/geomagnetic activity
J. Bochníček1, H. Davídkovová1,2, P. Hejda1, and R. Huth2,3 1Institute of Geophysics, Academy of Sciences of the Czech Republic, Boční II/1401, 141 31 Prague, Czech Republic
2Faculty of Science, Charles University, Albertov 6, 128 43 Prague, Czech Republic
3Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Boční II/1401, 141 31 Prague, Czech Republic
Abstract. 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.

Citation: Bochníček, J., Davídkovová, H., Hejda, P., and Huth, R.: Circulation changes in the winter lower atmosphere and long-lasting solar/geomagnetic activity, Ann. Geophys., 30, 1719-1726, https://doi.org/10.5194/angeo-30-1719-2012, 2012.
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