Contributions of the synoptic meteorology to the seasonal cloud condensation nuclei cycle over the Southern Ocean

Abstract

Cloud condensation nuclei (CCN) play a fundamental role in determining the microphysical properties of low-level clouds that are crucial for defining the energy budget over the Southern Ocean (SO). However, many aspects of the CCN budget over the SO remains poorly understood, including the role of the synoptic meteorology. In this study, we classify six distinct synoptic regimes over the Kennaook / Cape Grim Observatory (CGO) and examine their influence on the seasonal cycle of the CCN concentration (NCCN). Three "winter"regimes are dominant when the subtropical ridge (STR) is strong and centered at lower latitudes, while three "summer"regimes prevail when the STR shifts to higher latitudes...