Publikationsdatum:
2020-02-12
Beschreibung:
The role of the middle and upper atmosphere for climate has long been underestimated. Recent studies, however, indicate the influence of stratospheric dynamics on large scale weather phenomena. Within the frame of the DFG Priority Program “Climate And Weather of the Sun-Earth System (CAWSES)”, scientists from the GFZ German Research Centre for Geosciences, contributed to this topic. The studies focussed on the coupling of processes from the troposphere up into the high atmosphere. Our investigations were mainly based on data from the German CHAMP satellite. One of the surprising results is that tropospheric thunderstorms are able to excite global scale atmospheric tidal waves that were still detectable in air density and wind measurements by CHAMP at 400 km altitude. Another sensitive indicator of these tides in the ionosphere is the equatorial electrojet (EEJ). We have shown that the longitudinal variation of the EEJ intensity is controlled closely by the tropical thunderstorm distribution. Another, unexpected finding is that so-called sudden stratospheric warming (SSW) events in polar regions have a significant influence on the dynamics of the ionosphere at low latitudes. Also here the EEJ is a suitable indicator of the modifications. It has been shown that the lunar tidal signal of the EEJ is markedly amplified during SSW events. This characteristic feature may be suitable for identifying SSW occurrences for times from which no direct observations of sudden stratospheric warming exists. These examples show that long series of geomagnetic field records can be regarded as a suitable archive of climate variations and may help to improve the climate modelling.
Sprache:
Deutsch
Materialart:
info:eu-repo/semantics/article
Format:
application/pdf
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