oCean Atmosphere Interactions in the Antarctic regions and Convergence latitude – CAIAC - PNRA19_00009

Polar Boundary Layers (BL) are poorly understood but key elements of the Earth’s climate system through which energy, mass and momentum are redistributed between the different spheres. The changing polar BL structure and its role in the Earth’s climate system are central, but to-date severely understudied. Focusing on the sea, a high latitudes of Southern Hemisphere, the poor knowledge/observation of long-lived and shallow Marine Polar BLs (MPBL) and ocean-atmosphere interactions pose a very strong limitation to the understanding of climate changes. Actual estimations of the phenomenology are obtained mainly using a modelling approach.
We propose to fill the experimental gap and provide very relevant and necessary information on MPBL in Antarctic and on selected key processes, making use of the Laura Bassi, with an approach that combines in-situ observations and 3-D modelling. The overarching goal is to improve representation of MPBL dynamics and turbulence features in numerical weather prediction (NWP) models at different scales, leading to a better knowledge of radiative and cloud formation processes, with a particular attention on the role of aerosols. Observation activities will focus on i) determination of radiation surface components/budget as well as exchange fluxes at the sea-ice-atmosphere interfaces, and ii) characterization of primary and secondary aerosols, and their climate-relevant properties. The acquired data will support modelling activities of MPBL in three different sub-regions (open sea, mixed sea ice, full sea ice). Considering the limitation of commercial atmospheric instrumentation for operations on a mobile platform, a significant part of the project will be devoted to develop new technical solutions. We will also use the opportunity to collect information on selected parameters provided by automatic measurements during during the ship opportunities periods