The UK Chemistry and Aerosol Project (UKCA) ukca.ac.uk researchpages/glomap

1. The UK Chemistry and Aerosol Project (UKCA)www.ukca.ac.ukhttp://researchpages.net/glomap Ken Carslaw

2. UKCA • NCAS–Met Office programme to develop a community coupled aerosol-chemistry-climate model based on the Unified Model • Streamlines the aerosol and chemistry code in the UM to create a single “UKCA sub-model” • Project partners are the Hadley Centre and the Universities of Cambridge, Leeds (with Oxford and Reading) • Running since 2004

3. UKCA aerosol • UKCA aerosol sub-model is a significant advance on previous UM scheme • Much wider range of applications (consistent model across climate, air quality, Earth system research) • New features: • Dynamic aerosol size distribution • Full microphysics • Internal mixing of particles • Better radiative properties, CCN activity, etc. • New chemical components (NH4+, NO3-, SOA, etc) and coupled aerosol-chemistry

4. UKCA collaboration • Leeds: aerosol dynamics, composition, evaluation • Inorganic mixed aerosol composition collaboration with Manchester • Secondary organic aerosol development as part of the QUEST-QUAAC project • Met Office: Tropospheric chemistry, cloud chemistry, radiation coupling, UM sub-model coding • Cambridge: Trop and strat chemistry, nudging

5. UKCA wider collaboration • UKCA is a community model that will improve rapidly as it is applied and evaluated in many other projects. Current examples include: • The European Integrated Project (EUCAARI) using UKCA/UM as part of the Earth System modeling work package and campaign analysis • NERC APPRAISE Aerosol Programme (ADIENT direct effect and ACES organic aerosol consortia • Stratospheric aerosol and geoengineering in a NERC Cambridge/Leeds collaboration • Met Office CASE projects: Heterogeneous chemistry; Dust and DMS in the Earth System; Arctic aerosol/climate; Ozone indirect effects; Cloud drop number and indirect effect • UKCA is the basis for NERC’s new Earth System Model • Will be implemented in the ECMWF-IFS in the EU MACC project

6. One model, many applications The same aerosol/chemistry model is implemented in a CTM, a GCM, an Earth System Model and (from 2010) the ECMWF operational model ECMWF-Integrated Forecasting System (EU MACC project) Air quality prediction

7. UM UKCA in the Met Office Short-term numerical weather prediction & Visibility forecasts MACC project Seamless prediction AQUM project AQ forecasts UKCA Troposphere & Stratosphere & Aerosols Seasonal forecasting Decadal prediction Aerosol forcing Biogenic emissions JULES Climate projections AR5 - HadGEM2-ES UKCA-trop UKCA-strat Climate projections Post-AR5 HadGEM2/3-ES UKCA-whole atm UKCA-MODE Land surface Slide from O. Boucher, Met Office

8. Some model applications

9. Radiative forcing potential of regional SO2 emissions • CCN production from unit SO2 emission varies by a factor 3 between Asia, US and Europe SO4 CN CCN US Europe Asia Manktelow 2008 (NCAS student)

10. New particle formation • New particle formation substantially alters the magnitude of indirect forcing (+-50% regional changes) • A neglected process in existing climate models

11. Asian dust-sulphate interaction • Impact of the ACE-Asia “perfect dust storm” on SO4 aerosol much smaller than previously estimated (few % in most polluted regions) • Dust gets saturated with SO4 Dust loading (mg m-3) % sulphate on dust

12. Opportunities for collaboration • Impact of aerosol on Monsoon dynamics • Ideal application of UKCA-UM • Dust uplift and dynamics • Rapidly growing research community in the UK • Climate and Earth system applications (nutrients, long term change, etc), uplift micrometeorology, direct forcing, model development • Air quality-climate interaction • Single model • Policy driven research • Combined observation and modelling campaign focussed on aerosol and composition