External forcing increases the occurrence of internally generated extreme events of North Atlantic Oscillation and East Atlantic pattern ...

• Main Authors: Liu, Quan, Jungclaus, Johann, Matei, Daniela, Bader, Juergen
• Format: Conference Object
• Language: unknown
• Published: GFZ German Research Centre for Geosciences 2023
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: https://dx.doi.org/10.57757/iugg23-1793; https://gfzpublic.gfz-potsdam.de/pubman/item/item_5017794

<!--!introduction!--> External forcing is emerging as a factor influencing the internal variabilities of the climate system. However, the external forcing’s influence on the internal variabilities of the large-scale atmospheric circulation modes such as North Atlantic Oscillation (NAO) and East Atlantic (EA) pattern, has never been identified with a large ensemble model. The study analyzes the extreme events of NAO and EA using geopotential height data of the Max Planck Institute Grand Ensemble (MPI-GE) with 100 ensemble members. The internal variability is quantified as the deviation from the ensemble mean. The extreme NAO and EA are defined as those years where the indexes are above (positive extremes) or below (negative extremes) 2 standard deviations. The influence of global warming on the internal variability is checked with a 1pcCO2 experiment, where the CO2 concentration is increased by 1% every year. The results show increased occurrence of extreme events, especially negative extremes, for both ... : The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) ...