Dr. Buwen Dong

Reading University, UK

Room 303, Keyan Building

10:00, Sept 11, 2017

Extremes of weather and climate events at global and regional scales can have devastating effects on human society and the environment. It is vital to understand how their intensity and frequency change with climate change. In this talk, how to frame the attribution question will be reviewed and some examples of climate event attributions are discussed. Then two sets, one with coupled model and other with the same AGCM, of experiments are used to assess whether the attribution statements for forced decadal changes between two periods across the mid-1990s are sensitive to air-sea coupling. The results indicate that attribution conclusions for surface air temperature changes derived from AGCM experiments are generally robust and not sensitive to air-sea coupling. However, changes in seasonal mean precipitations, and circulation in some regions show large sensitivity to air-sea coupling, notably for the East Asian summer monsoon. Further the relative roles of changes in greenhouse gases (GHGs) and anthropogenic aerosols (AA) on forced decadal EASM change are presented. Results indicate that changes in GHGs increase precipitation over southern China, whilst changes in AA dominate in the drought conditions over northern China with total response giving south-flooding-north-drought pattern, indicating a role of changes in anthropogenic forcing on decadal change in precipitation over East Asia across the mid-1990s.