Invited Speaker: Interactions in the cloud-atmospheric boundary layer-surface (CAS) system over Arctic sea ice in observations and WRF simulations

Over Arctic sea ice, the processes governing the interactions between the Arctic atmosphere and the surface are modulated by the clouds within and at the top of the atmospheric boundary layer, the atmospheric boundary layer, and the surface characteristics, and are closely linked. Process-oriented diagnostics of observations and model output give insight to the individual processes and the preferred states of this cloud-atmospheric boundary layer-surface (CAS) system. Other linkages can be illustrated based on a variety of surface-boundary layer, cloud-boundary layer, or cloud-surface diagnostics. Example diagnostics will be shown to illustrate 1) the close connection between the structures, properties, and processes associated with the three components of the CAS system, 2) key responses and preferred states of the CAS system, and 3) the use of CAS-system process diagnostics for validating model output. Examples will illustrate the impacts of a) sea-ice surface heterogeneity on turbulent fluxes and the boundary-layer structure; b) large-scale forcing on surface fluxes and boundary-layer structure; and c) surface albedo on multiple reflections and net surface energy flux. Observations and simulations from the 2004 Mixed-Phase Arctic Cloud Experiment (MPACE), the 1998 Surface Heat Budget of the Arctic Ocean (SHEBA), the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC), and the 2008 Arctic Summer Cloud-Ocean Study (ASCOS) field programs are being examined and will be used as examples.