Midlatitude Oceanic Cloud and Precipitation Properties as Sampled By the ARM Eastern North Atlantic Observatory

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Giangrande, Scott E., Wang, Die, Bartholomew, Mary Jane, Jensen, Michael, Mechem, David B., Hardin, Joseph, Wood, Robert
• Language: unknown
• Published: 2021
• Subjects: 54 ENVIRONMENTAL SCIENCES; North Atlantic
• Online Access: http://www.osti.gov/servlets/purl/1504386; https://www.osti.gov/biblio/1504386; https://doi.org/10.1029/2018JD029667

Marine low clouds are critical to the climate system because of their extensive coverage and associated controls on boundary layer dynamics and radiative energy balance. The primary foci are marine low cloud observations over a heavily instrumented site on the Azores archipelago in the eastern North Atlantic (ENA) and their associated raindrop size distribution (DSD) properties, relative low-cloud contributions to the precipitation, and additional sampling (instrument, environmental) considerations. The contribution from low clouds (e.g., cloud top < 4 km) to the overall precipitation over midlatitude oceans is poorly understood, in part because of the lack of coupled, high-quality measurements of precipitation and low-cloud properties. Cloud regime and precipitation breakdowns performed for a multi-year (2014-2017) record emphasize diurnal precipitation and DSD characteristics for both low and deeper clouds, as well as differences between the two disdrometer types used. Results demonstrate that marine low clouds over this ENA location account for a significant (45%) contribution to the total rainfall and exhibit a diurnal cycle in cloud (thickness, top, base) and precipitation characteristics similar to satellite records. Additional controls on observed surface rainfall characteristics of low clouds allowed by the extended ground-based facility datasets are also explored. From those analyses, it is suggested that the synoptic state exerts a significant control on low-cloud and surface precipitation properties.