Zusammenhang zwischen Schwankungen der Meeresoberflächentemperatur und dem Wasserdampfeintrag in die Stratosphäre in einer Zeitscheibensimulation des gekoppelten Atmosphäre-Ozean-Modells EMAC-O / Gutachter: Univ. Prof. Dr. Ulrike Langematz
Lenard Müßig / Masterarbeit – 2016
Abstract: Current studies (e.g. Gar_nkel et al., 2013) showed a connection between the variation of sea surface temperatures and the water vapor entering the stratosphere. Therefore this work will focus on the question, whether this connection also exists in the data of the chemistry-climate model coupled with an ocean model EMAC-O. The used Dataset was a time slice simulation of the coupled model with 1960 conditions in ODS and GHG. A _rst study was made to investigate the variability of H2O and SST. Following the hightest variability existed in the tropical paci_c and include the El Ni~no Southern Oscillation (ENSO). Therefore, the whole spectrum of ENSO versions (El Ni~no, Modoki El Ni~no, La Ni~na, Modoki La Ni~na) and the warm and coldphases of the Paci_c Warmpool Region will be analyse. Thereby it can be shown that the El Ni~no versions indicate reasonable and plausible results which can be explained by the thesis of Gar_nkel el al. (2013). Accordingly, the east paci_c events (El Ni~no or La Ni~na) shows a signi_cant input of water vapor into or dehydration of the stratosphere. In contrast to that, the central paci_c events indicates a non-signi_cant entry of water vapor into or dehydration of the stratosphere. These di_erences are interpretet by Gar_nkel et al. (2013) with three fundamental relations. 1.: the existence of a strong change in the atmospheric circulation (Walker-Circulation), 2.: this induces a warming in the tropical tropopausal layer, 3.: followed by movement of the cold point region (CPR). Due to the fact that these relations are due to a thermal changing of the tropopausal conditions, the entry of water vapor into the statosphere will be regulated in a dominant way by this. Nevertheless the clearness of the results mainly depending on the used method of classi_cation. To investigate the spread and the inuence of the classi_cation methods we discuss four di_erent methods and elaborate their advantages and disdavantages. In order to that there can be found the best possible method to indicate EPW and CPW in the data of EMAC-O. The following investigation of the warm and coldphase of the Paci_cWarmpool Region indicated that there were major di_erences in the water vapor entering the stratosphere, which correlated to the di_erent conditions of the sea surface temperature. Afterwards we conducted a korrelationanalysis between the tropical sea surface temperatures and the water vapor anomalies in 80 hPa. There we also found the connection between these two meteorological parameters. In addition the QBO itself and the di_erent combinations of ENSO and QBO have an inuence on the thermal conditions at the Tropopause. Further studies (e.g. Liang et al., 2011) showed that. Therefore, all eight possible combinations of ENSO and QBO will be analyse. Thus it can be shown that all combinations of ENSO and QBO due to signi_cant moistening or dehydration of the stratosphere. The remaining combinations also due to reasonable and plausible results which can be explained by the thesis of Liang et al. (2011). In fact, the combinations of ENSO and QBO in phase shows signi_cant moistening or dehydration of the stratosphere. The remaining combinations of ENSO and QBO out of phase shows on the one hand (E-Q+) a greatly reduced up to not any positive or negative water vapor anomalies and on the other hand (E+Q-) an enhanced moistening of the stratosphere. Finally it could be summerised that the by Gar_nkel et al. (2013) ond Liang et al. (2011) described connection between the variation of sea surface temperatures and the water vapor entering the stratosphere could be shown in the Data of the coupled chemistry-climate model EMAC-O.