Comparisons of satellite observations and climate model output indicate significant biases to the south of New Zealand resulting in too much sunlight hitting the surface of the Southern Ocean ad sea surface temperature biases. The substantial warm biases in Southern Ocean sea surface temperatures have been attributed to deficiencies in the simulation of clouds, including too little low-level cloud cover and a lack of reflective super-cooled liquid water clouds. Further quantification of the partitioning between ice and mixed phase cloud above the Southern Ocean is required to provide model constraints and will be the focus of this presentation. Given the prevalence of low-level cloud identified in shipborne observations and the difficultly of sampling these clouds using satellite observations, we need to combine ground-based and satellite observations. In particular, we will discuss the use of satellite and ground-based measurements to probe the vertical profile of clouds to quantify the proportions of mixed phase and ice clouds as a function of altitude. This dataset will then be directly compared to climate model output that has been processed via the COSP satellite simulator.