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Process work on the coupling of cloud microphysics, dynamics, radiation Steven Dobbie

This project at the Institute for Climate and Atmospheric Science (ICAS) focuses on the coupling of cloud microphysics, dynamics, and radiation. It investigates the impact of glassy aerosols on TTL cirrus clouds and explores the ice nucleation process. Collaborations with experts in the field and advanced modeling techniques are used to improve understanding of cloud properties.

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Process work on the coupling of cloud microphysics, dynamics, radiation Steven Dobbie

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  1. Institute for Climate and Atmospheric Science (ICAS) • Process work on the coupling of • cloud microphysics, dynamics, radiation • Steven Dobbie

  2. Institute for Climate and Atmospheric Science (ICAS) Micro Macro/Cloud Regional/Global Optics - Mie - DDA - ADA RT - 2/4 stream - thin atm - MC RT GCM - CCCMA GCMIV - UM Rad Cloud LEM Regional/Global Bin-LEM APSC Aerosol TGDC iGen Micro Macro/Cloud

  3. Institute for Climate and Atmospheric Science (ICAS) Micro Macro/Cloud Regional/Global Sc entrainment iGen (Dan) Arctic stratus ASCOS (Ian, Tom, MO) CASE Radiative forcing Cloud Contrail cirrus (Piers, Alex, MO) COSIC Cirrus: TTL cloud glassy (Ben, Theo, Jim) GCSS WG2 (Sardar, Huiyi, MO) Aerosol Ice nucleation Lab (Ben, Theo, Jim) ERC Rad Sulphate (Jiangnan)

  4. Institute for Climate and Atmospheric Science (ICAS) Micro Macro/Cloud Regional/Global Sc entrainment iGen (Dan) Arctic stratus ASCOS (Ian, Tom, MO) CASE Radiative forcing Cloud Contrail cirrus (Piers, Alex, MO) COSIC Cirrus: TTL cloud glassy (Ben, Theo) GCSS WG2 (Sardar, Huiyi, MO) Aerosol Ice nucleation Lab (Ben, Theo) ERC Rad Sulphate (Jiangnan)

  5. Institute for Climate and Atmospheric Science (ICAS) Cloud nucleation (Dobbie): AIDA Chamber, Karlsruhe Cloud Processes Chamber, Leeds - Studying ice nucleation of glassy aerosols relevant for TTL. New class of ice nuclei. CP Chamber now cooled using liquid nitrogen - Investigating impact on cirrus clouds Kulkarni, G; Dobbie, S; McQuaid, J B, AMT, p221-229, 2009 Collaboration with Ben Murray, Theo Wilson, Jim Atkinson (shared PhDs)

  6. Institute for Climate and Atmospheric Science (ICAS) AIDA results Glassy organic aerosol used in AIDA chamber New pathway for het ice nucleation at TTL

  7. Institute for Climate and Atmospheric Science (ICAS) AIDA results

  8. Institute for Climate and Atmospheric Science (ICAS) Effect of glasses on TTL cirrus (Dobbie) Idealised 1D Advanced Particle Simulation Code (APSC) results Glassy particles can have dramatic effects on cloud properties, especially: - mean ice size a factor of 2 larger - order of magnitude lower concentrations May explain the high in-cloud ice supersaturations Collab: Ben Murray and Theo Wilson (Chem)/Sardar Al-Jumur (PhD students)

  9. Institute for Climate and Atmospheric Science (ICAS) GCSS WG2 (Dobbie, chair) GCSS WG 2 - ARM SGP cirrus inter-comparison 1D/2D/3D, UKMO LEM, Yang/Dobbie, Leeds, UK 1D, UM, Wilson, UKMO, UK 1D/2D/3D, Eulag, Sölch/Kärcher, DLR, Germany 1D/2D, Monier, Clermont, France SCM ECHAM5, Heidt/Lohmann, ETH, Switzerland 2D, LES/Lag, Grabowski/Morrison, NCAR, USA SCM CCMIV, von Salzen/Cole, CCCMA, Canada SCM ECMWF, Forbes, ECMWF, UK

  10. Institute for Climate and Atmospheric Science (ICAS) GCSS WG2 (Dobbie, chair) - Reasonable agreement between LEM models - Wide divergence of results for GCMs in SCM PhD student Huiyi Yang (postdoc at Oxford)

  11. Institute for Climate and Atmospheric Science (ICAS) GCSS WG2 (Dobbie, chair) • GCMs over predicting thickness of layer compared to observations (vertical res, subgrid param, etc.) • LEMs agree reasonably well but comparison has highlighted some areas of improvement (UK LEM overpredicts number concentration, etc). PhD student Huiyi Yang (postdoc at Oxford)

  12. Institute for Climate and Atmospheric Science (ICAS) COSIC (Forster, Dobbie, Rap, + MO, Manchester, Reading, DLR) • BAE 146 contrail observations and analysis • LEM integrations • UM Contrail and cirrus scheme • Radiative forcing estimate of contrail cirrus

  13. Governing Model (eg LEM) Parameterized Model (eg GCM) Accurate but slow Fast but inaccurate Governing Equations Physical System Institute for Climate and Atmospheric Science (ICAS) Cloud parameterisation (Dobbie) Dan Tang, NERC PhD

  14. iGen Governing Model (eg LEM) Parameterized Model (eg GCM) Accurate but slow Fast but inaccurate Governing Equations Physical System Institute for Climate and Atmospheric Science (ICAS) Cloud parameterisation (Dobbie) Dan Tang, NERC PhD Fast and accurate • iGen analyses source code and creates a parameterisation with error estimate • Factor of about 100 faster for cases studied • Addressing param of Sc cloud-top entrainment

  15. Institute for Climate and Atmospheric Science (ICAS) • iGen • Particle in a box, showed p=k*v^2 (If statements) • Reproduced Lorenz type parameterisation • iGen has also successfully analysed a model of turbulent fluid flow (with 1.5 order turbulence closure) which demonstrates a more complex application of gridded finite-difference equations than Rayleigh-Benard convection • Mie optics which demonstrates iGen’s ability to deal with the sharp peaks in output response caused by resonances •  Cloud-top entrainment of Sc cloud

  16. Institute for Climate and Atmospheric Science (ICAS) Arctic Cloud Modelling (Dobbie) Tom Pleavin (NERC Case PhD) (I. Brooks, Dobbie, Met O) • Modelling of arctic BL cloud with LEM & bin-resolved microphysics Micro-meteorology masts Tethered balloon SODAR ICAS measurements on the ice…

  17. Institute for Climate and Atmospheric Science (ICAS) ASCOS First comprehensive observations in the central arctic: Using the LEM to understand the complex couplings between cloud, radiation, dynamics, and the surface fluxes. - How do the clouds maintain frequently 100s metres into the inversion? - Where are the aerosols coming from? - How important is the coupling with the surface for arctic stratus?

  18. Institute for Climate and Atmospheric Science (ICAS) Geo-Engineering Climate Collaboration with Finland: - Detailed cloud simulations with BR-LEM to determine if ship injections of sea-salt will lead to higher reflectivity Sc clouds - Glassy particles – change the lifetime of cirrus?

  19. Institute for Climate and Atmospheric Science (ICAS) • Future • -Cloud Processes Chamber research: • - glassy particles and cloud impacts (ERC/Murray, Dobbie, Wilson). • - Memory effect of IN (submitted to NERC Dobbie/Murray) • -COSIC • - 1st good estimate of the radiative forcing of contrail cirrus. • (Forster, Rap, others) • GCSS WG2 • - Writing up papers on current inter-comparison (Dobbie/Huiyi/others) • - Influence of GW on cirrus microphysics (Dobbie, Jumur)

  20. Institute for Climate and Atmospheric Science (ICAS) • Future • iGen • - parameterization of stratocumulus entrainment (NERC, Tang Dobbie) • ASCOS: • - LEM/BR-LEM studies of dynamics, microphysics, and radiation of • arctic stratus (NERC, Brooks, Dobbie, Pleavin). • Geo-Engineering Climate • BR-LEM simulations of Sc and cirrus

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