Understanding Oceanic Low-level Clouds


Using a combination of ground-based ARM data and satellite data, DOE scientists found that low-level clouds that usually form over the oceans are controlled by interactions between cloud small-scale processes (known as microphysical processes) and large-scale processes (known as macrophysical processes). Despite their critical importance in shaping the Earth’s climate, these low low-level clouds are not well understood. For the first time, this study found that there is striking seasonal variation in both macrophysical properties (such as cloud base height and cloud amount) and microphysical properties (such as number of cloud droplets and drizzling frequency). The results suggest possible influences of macrophysical processes and aerosol particles, highlighting the need for development of a new cloud formulation that accounts for both microphysical and macrophysical processes.


Liu, Y. 2010. Comments on “Seasonal Variation of the Physical Properties of Marine Boundary Layer Clouds Off the California Coast” by Lin et al., Journal of Climate 23(12), 3416–3420. DOI:http://dx.doi.org/10.1175/2010JCLI3407.1.