Workshop on the Clouds, Precipitation and Meteorology over the Southern Ocean Christian Jakob Alain Protat Steve Siems Tuesday 27 November 2012

Revision of Southern Ocean Clouds Model & Analysis Evaluation Trenberth & Fasullo (2010) J Clim Trenberth & Fasullo (2010) J Clim Recent Satellite Climatologies Mace (2010) JGR Mace (2010) JGR Hu et al (2010) JGR Hu et al (2010) JGR Mace et al (2007) GRL Mace et al (2007) GRL Bennartz (2007) JGR Bennartz (2007) JGR Aerosol Characterization Experiment ACE-1 (1995) Russell et al (1998) JGR Russell et al (1998) JGR Boers et al (1998) JGR Boers et al (1998) JGR Bates et al(1998) JGR Bates et al(1998) JGR Southern Ocean Cloud Experiments SOCEX I & II (1993 & 1995) Boers et al (1996 & 1998) JGR Boers et al (1996 & 1998) JGR Jensen et al (2000) AR Jensen et al (2000) AR Yum & Hudson (2004) AE Yum & Hudson (2004) AE Various CSIRO flights Twomey & Warner (1967) JAS Twomey & Warner (1967) JAS Mossop et al (1970) JAM Mossop et al (1970) JAM Paltridge (1976) JGR Paltridge (1976) JGR Platt (1976) QJRMS Platt (1976) QJRMS Stephens (1978) JAS Stephens (1978) JAS

Revision of Southern Ocean Clouds Q: What makes the meteorology & clouds over the Southern Ocean unique compared to the Northern Hemisphere? A:The absence of land at the surface. Absence of terrestrial aerosols (dust) Absence of anthropogenic aerosols Q: Are SO clouds & precipitation fundamentally different due to the microphysics? Absence of a no-slip boundary leading to stronger surface winds, waves and sea spray Q: Is Monin-Obukhov similarity theory even valid? Q: Do we understand cloud & precipitation processes in the SO boundary layer?

The air is pristine. Yum and Hudson (2004 Atmospheric Environment) looked at CCN concentrations from various field experiments. The lowest concentrations of CCN observed was during SOCEX-1 (winter) off the coast of Tasmania.

There is a lot of wind, wind shear, waves and sea spray. During ACE-1, Russell et al looked at the mixing between the boundary layer ( m) and a thick buffer layer (~1000 m) immediately above the boundary layer. Intermittent turbulence was evident in this buffer layer with fluxes from both above and below. Jensen et al (2000) found wind shear at the cloud tops during SOCEX.

Objectives for the Day The immediate aims of this workshop are to: identify the research interests in studying these weather systems and their associated cloud and precipitation patterns, identify the research interests in studying these weather systems and their associated cloud and precipitation patterns, What are the outstanding scientific questions? discuss how best to utilise the future observations of the RV Investigator and Cape Grim and facilitate wider collaboration. discuss how best to utilise the future observations of the RV Investigator and Cape Grim and facilitate wider collaboration. What are the opportunities? Further aims are to focus and present these research challenges and opportunities to the wider scientific community in an effort to eventually design the scientific objectives of an international field campaign.

Why/where/when is the radiative budget off over the Southern Ocean? What are the inconsistencies between the simulated and observed cloud fields? What are the dominant cloud regimes, and what are their properties? Are the cloud microphysical properties of SO clouds unique relative to the NH? Is the atmospheric boundary layer over the SO unique due to winds, waves & sea spray? Is sea spray being overlooked? Wind shear? What are the inconsistencies between the simulated and observed surface fluxes? How well are we modeling fronts & precipitation given the sparse observations? What is the meteorology of the different cloud regimes? What are the inconsistencies between the simulated and observed cold fronts? What are the observational challenges in this region?