ETH On-going and planned projects with ECHAM Martin Wild, Doris Folini, Adeline Bichet, Maria Hakuba, Christoph Schär IACETH

ETH Simulations with ECHAM5-HAM Model ECHAM5-HAM (updated from Stier et al. 2005), Version Oct Detailed aerosol treatment (prognostic equations for number and mass) Experiments (carried out by Doris Folini at CSCS) - Transient simulations (atmosphere only, prescribed SSTs) - Historic emission inventories: NIES - Resolutions from T42L19 to T106L31 List of Ensembles Simulations#members: 1870 – 2000, default “all forcings“ simulations, T42 (T63)13 (9) Sensitivity experiments: 1950 – 2000, SO2 emissions at level of 1950, T – 2000, BC / OC emissions at level of 1950, T – 2000, all anth. aerosol emissions constant, T42 (T63) 6 (3) 1870 – 2000, all anth. aerosol emissions constant, no volcanoes: – 2000, fixed climatological SSTs, T42 (T63)13 (1)

ETH What are the origins of these changes? What is their impact on climate system components and climate change? How will these components evolve in the future? Atmospheric transmission Wild et al. 2005: Science 308 “dimming” “brightening” Research focus Significant decadal changes in the observed components of the Earth energy and water balance Observed precipitation NH mean land “dimming” “brightening”

ETH What are the origins of these changes? => sensitivity studies, impact of various types of aerosol on decadal changes in surface solar radiation Research focus: origins of changes Surface solar radiation: constant versus variable aerosol emissions Varying only SO 2 or BC emissions Folini et al. in prep. constant aerosol emissions variable aerosol emissions

ETH Impact of dimming on precipitation in China Suppression of precipitation with dimming in China constant aerosol emissions historic aerosol emissions Annual mean precipitation Research focus: impacts

ETH Impact of dimming on precipitation in China Suppression of convective precipitation with dimming Summer precipitation large scale convective total precipitation JJA constant aerosol emissions variable aerosol emissions

ETH PhD Thesis Adeline Bichet: Precipitation evolution since the late 19th century Research focus: impacts Bichet et al., submitted Impact of SSTs and aerosols on global land precipitation

ETH Research focus: impacts Master Thesis Maria Hakuba Impact of reduced Greenland topography on precipitation Overall increase in precipitation with decreasing topography Change in precipitation with topography reduced by 50% T106 simulations

ETH Research focus: scenarios Surface clear sky insolation in NH midlatitudes ECHAM5-HAM with ENSEMBLE SSTs Transition into a new dimming? Coupled model desirable How will the Earth energy and water balance components evolve in the future?

ETH Research focus on changes in the energy and water cycles based on multidecadal transient simulations Near term experiments: Carry out multidecadal transient simulations with new model versions ECHAM6 and ECHAM6-HAM (sensitivity studies) Use ECHAM6-HAM with new emission inventories from IPCC AR5, comparison to NIES and other inventories, comparison to earlier ECHAM5- HAM simulations Mid term experiments: Use a coupled Atmosphere-Ocean version of ECHAM6 (ECHAM6-HAM?) to study impacts of changes in the radiation balance on various climate system components including ocean feedbacks. High resolution (T213?) time slice experiments for present and future climates (e.g. for mass balance changes of polar ice sheets) All simulation data can be made available to other interested groups Future Plans with ECHAM

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