Full ACE-ENA Cloud Droplet Size Distribution Data Set Available

Published: 22 April 2022
The x-axis shows time in UTC from 09:00 to 12:00 on July 18, 2017, at the Eastern North Atlantic atmospheric observatory. The y-axis shows cloud droplet size distribution with a diameter from 10^1 to 10^3 um.
This sample plot shows the cloud droplet size distribution in time for one research flight on July 18, 2017, as measured by the holographic detector of clouds (HOLODEC) during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) campaign.

A fully processed data product providing cloud droplet size distribution by aircraft measurements is available from the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) field campaign.

The Atmospheric Radiation Measurement (ARM) user facility conducted the ACE-ENA campaign in summer 2017 and winter 2018. During ACE-ENA, the ARM Aerial Facility flew the Gulfstream-159 (G-1) research aircraft over ARM’s Eastern North Atlantic atmospheric observatory.

The ACE-ENA cloud size distribution data product is useful for scientists to drive or constrain models and validate model simulations, as well as examine cloud microphysical properties. It can be used whenever size-resolved cloud and small precipitation droplet concentration is needed. The product covers a wide range of droplet sizes from cloud droplets to small raindrops (10 µm up to approximately 1,000 µm in diameter).

Please note that this is a field campaign data set, which is limited in time and space.

This product is based on the data from the holographic detector of clouds (HOLODEC). Mounted on an aircraft wing, this cloud probe provides three-dimensional locations of droplets within a sample volume and produces two-dimensional images of the detected drops.

Four cloud probes are identified on a research aircraft.
This photo shows cloud probes mounted underwing on ARM’s Gulfstream-159 (G-1) research aircraft during ACE-ENA: HOLODEC, the fast cloud droplet probe (FCDP), two-dimensional stereo probe (2D-S), and high-volume precipitation spectrometer (HVPS).

The original data were acquired on the ACE-ENA G-1 flights during two intensive operational periods (IOPs): June 21 to July 20, 2017, and January 19 to February 19, 2018. HOLODEC collected close to a terabyte of data from most flights, and the data roughly doubled during processing.

Previously released data have been extended to include all 39 research flights from ACE-ENA, completing the data set. Most of the processing took place on ARM’s Stratus and Cumulus high-performance computing clusters.

The data are presented in the ICARTT format, which is a comma-separated value format, and accompanied by a README file with details of data origin and processing.

Scientists can now use the full data set of size-resolved cloud droplet concentration from HOLODEC. The largest measurable size of cloud droplets is limited by the size of the sample volume and the number concentration.

This data set is created with two different levels of quality, with higher precision for the first IOP. Data from the second IOP includes slightly more noise, which will be removed in a future data release after more work.

For questions or to report data problems, please contact Susanne Glienke or Raymond Shaw.

Access the data set in the ARM Data Center. (Go here to create an account to download the data.)

To cite the data, please use doi:10.5439/1617265.

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ARM is a DOE Office of Science user facility operated by nine DOE national laboratories.