Die Antarktis ist ein phantastisches Freiland-Forschungslaboratorium. Eine Vielzahl von Forschungsstationen ist über den Kontinent verteilt, darunter auch die russische Station Wostok. Mithilfe von Eisbohrkernen wurde die Klimageschichte der vergangenen 11.000 Jahre detailliert rekonstruiert. Im Januar 2015 veröffentlichten Zhao und Feng im Journal of Atmospheric and Solar-Terrestrial Physics eine Studie in der sie die Temperaturentwicklung mit dem Verlauf der Sonnenaktivität verglichen. Die Forscher entdeckten in der Temperaturkurve charakteristische Zyklen, die dem solaren Suess-de Vries Zyklus (208 Jahre) und Eddy Zyklus (1000 Jahren) entsprechen. Auffällig war ein leichter Zeitverzug zwischen solarem Auslöser und Temperaturreaktion von 30-40 Jahren. Die Wissenschaftler schlussfolgern, dass Sonnenaktivitätsschwankungen eine große Rolle in der Ausgestaltung der antarktischen Klimaentwicklung spielen. Hier der Abstract der Arbeit:
Correlation between solar activity and the local temperature of Antarctica during the past 11,000 years
The solar impact on the Earth’s climate change is a long topic with intense debates. Based on the reconstructed data of solar sunspot number (SSN), the local temperature in Vostok (T), and the atmospheric CO2 concentration data of Dome Concordia, we investigate the periodicities of solar activity, the atmospheric CO2 and local temperature in the inland Antarctica as well as their correlations during the past 11,000 years before AD 1895. We find that the variations of SSN and T have some common periodicities, such as the 208 year (yr), 521 yr, and ~1000 yr cycles. The correlations between SSN and T are strong for some intermittent periodicities. However, the wavelet analysis demonstrates that the relative phase relations between them usually do not hold stable except for the millennium-cycle component. The millennial variation of SSN leads that of T by 30–40 years, and the anti-phase relation between them keeps stable nearly over the whole 11,000 years of the past. As a contrast, the correlations between CO2 and T are neither strong nor stable. These results indicate that solar activity might have potential influences on the long-term change of Vostok’s local climate during the past 11,000 years before modern industry.
In diesem Zusammenhang ist auch eine Arbeit von Volobuev zu erwähnen, die im Mai 2014 in Climate Dynamics publiziert wurde. Der Autor beschreibt für die Region der Wostok-Station eine „relativ hohe Klimasensitivität“ für den solaren Temperaturantrieb. Hier die Kurzfassung:
Central antarctic climate response to the solar cycle
Antarctic “Vostok” station works most closely to the center of the ice cap among permanent year-around stations. Climate conditions are exclusively stable: low precipitation level, cloudiness and wind velocity. These conditions can be considered as an ideal model laboratory to study the surface temperature response on solar irradiance variability during 11-year cycle of solar activity. Here we solve an inverse heat conductivity problem: calculate the boundary heat flux density (HFD) from known evolution of temperature. Using meteorological temperature record during (1958–2011) we calculated the HFD variation about 0.2–0.3 W/m2 in phase with solar activity cycle. This HFD variation is derived from 0.5 to 1 °C temperature variation and shows relatively high climate sensitivity per 0.1 % of solar radiation change. This effect can be due to the polar amplification phenomenon, which predicts a similar response 0.3–0.8 °C/0.1 % (Gal-Chen and Schneider in Tellus 28:108–121, 1975). The solar forcing (TSI) is disturbed by volcanic forcing (VF), so that their linear combination TSI + 0.5VF empirically provides higher correlation with HFD (r = 0.63 ± 0.22) than TSI (r = 0.50 ± 0.24) and VF (r = 0.41 ± 0.25) separately. TSI shows higher wavelet coherence and phase agreement with HFD than VF.
