Clouds Across the Arctic: Synthesizing Knowledge from Ground-based Observations

Over the past two decades Arctic clouds have become increasingly appreciated as a major component of the Arctic system, playing an obvious role in energy transfer processes that are relevant for the changing Arctic surface. Observations of Arctic clouds have been increasing dramatically. In particular, ground-based measurements offer a very detailed perspective on clouds that is continuous in time, captures the diurnal cycle, and offers the ability to compare with other coincident measurements. Ground-based measurements also provide key data sets for evaluating satellite-based cloud observations that are critical for expanding cloud knowledge to regional and global scales. The expanding network of ground-based Arctic cloud observations has offered key insights into detailed cloud processes that control their phase and longevity, and a basis for examining the spatial variability of cloud properties among sites.  They offer the potential to determine those aspects that are inherent to clouds themselves regardless of their environment versus those that are influenced by location or local conditions. This presentation pulls together ground-based observations from Arctic sites in Alaska, Canada, Greenland, and over the Arctic Ocean to synthesize our understanding of clouds across the Arctic, specifically examining cloud occurrence, phase, microphysical properties, and radiative effects.