Can weekly cycles be used to determine the climatic response to anthropogenic aerosol loading?  Useful for getting around the problems of trend analysis  Signal likely to be small hence lots of data needed  AIM: To determine a quantitative link between aerosol loading and consequent surface forcing Constrain aerosol direct and indirect effects David Ridley (Supervisors: K. Carslaw, M. Chipperfield)

DTR Weekend Effect

Likely Causes  Synoptic weather events  Anthropogenic sources of pollution Need to determine the significance of the second cause

Cycles in DTR

Anomalies  Why is there no significant ‘weekend effect’ in Europe?  Why does the sign of the ‘weekend effect’ change?

DTR Weekend Effect

AOT Weekend Effect

Further Work  Use phase of ‘weekend effect’ to investigate transport  Explore weekly cycle in contrails to determine their role  Use seasonal results to help understand processes  Using GLOMAP to model aerosol weekly cycle  Use RTM to determine the surface forcing expected