题目：Clouds and Precipitation over Southern Australia and the Southern Ocean
报告人：Prof. Michael Manton
(School of Earth Atmosphere and Environment, Monash University )
The mountains of south eastern Australia promote orographic precipitation associated with wintertime cold fronts that provides water for much of south eastern Australia. Among the many uses of the water is the generation of hydro-electricity in the Snowy Mountains and the western mountains of Tasmania. The mountains, which are around 1500 m high, lead to a high frequency of supercooled liquid water (SLW) across the cool season. Although numerical models can capture the features of the cloud and precipitation associated with winter cold fronts, cloud phase and the distribution of surface precipitation are found to be sensitive to the microphysical parameterisation used in the models.
Systematic bias in climate models in the shortwave radiation over the Southern Ocean is associated with challenges in the representation of the atmospheric boundary layer and its associated clouds. Liquid-water clouds are common over the Southern Ocean, and their properties are found to be correlated with variations in the sea-surface temperature. For areas with open cellular convective clouds, there is evidence of active ice multiplication processes that lead to mixed-phase clouds and drizzle. It is likely that satellite measurements are challenged in identifying these clouds accurately. A number of current field campaigns in south eastern Australia and the Southern Ocean should help resolve the challenges in observing and modelling the clouds of these regions.