Die Veränderungen des Luftdrucks im IPCC A1B Szenario: Mittlerer Zustand und Muster der Variabilität

• Main Author: Bayr, Tobias
• Format: Thesis
• Language: German
• Published: 2010
• Subjects: Climate change; Greenland; North Atlantic; Aleutian Islands
• Online Access: https://oceanrep.geomar.de/id/eprint/10207/; https://oceanrep.geomar.de/id/eprint/10207/1/TBayr_Dipl_2010.pdf

Sea level pressure (SLP) is an important meteorological and climatological parameter, which gives information about the state of the atmospheric circulation. In this Diploma thesis, an investigation of changes in the mean state and patterns of variability of SLP is presented, with special scope on changes in the patterns of variability. For this analysis a multi model ensemble of 23 climate models for 20C3M and A1B scenario of the IPCC is used. In these simulation of a warming climate the mean SLP increases over the tropical Indo-Pacific region and decreases over the tropical Atlantic region. It could be shown, that there is a strong contrary linkage between the temperature change of the air column and the SLP change in the tropics. In the extratropics of both hemispheres an increase in SLP over the subtropics and a decrease over the polar regions is detected. As in former studies a strong link between extratropical SLP response and the positive trend in the Arctic Oscillation (AO) in the northern hemisphere (NH) and the Southern Annular Mode (SAM) in the southern hemisphere was found. In addition it could be demonstrated in this thesis that a part of the SLP change in the arctic, especially near the Aleutian islands, is due to a positive trend in the Pacific North American (PNA) pattern. It could be shown, that these changes are related to an increase in the jet stream windspeed, which are caused by the strong warming in the upper tropical troposphere, that influences the large scale circulation. The patterns of variability were obtained with an Empirical Orthogonal Functions (EOF) analysis, and with the new Distinct Empirical Orthogonal Functions (DEOF) analysis are those patterns determined, which strongest gain or lose relevance in climate change. In EOF analysis the explained variance of the dominant mode decreases in both hemispheres in summer. The result of the DEOF analysis can illustrate, that in boreal summer the AO weakens over Greenland, the North Atlantic and the Northeast Pacific and in austral ...