The three-dimensional distribution of clouds around Southern Hemisphere extratropical cyclones

The organization and, for the first time, the three-dimensional structure of clouds associated with the Southern Hemisphere cyclones are studied using active observations from the CloudSat and CALIPSO satellites. First, a composite cyclone is constructed from more than 800 individual cases in the years 2007 and 2008 using the cyclone centre as the composite reference point. It is shown that the three-dimensional cloud distribution around the composite cyclone agrees well with conceptual models of extratropical cyclones. Composite mean fields of sea level pressure, vertical motion, potential temperature and relative humidity are superposed on the three-dimensional cloud structure to better define the relationship between the clouds and dynamical properties of extratropical cyclones. The methodology used here reveals the relationship between dynamical and cloud processes in three dimensions around cyclones and provides the foundation for in-depth evaluations of the ability of climate models to simulate the cloud and dynamical structures of Southern Hemisphere extratropical cyclones.