CIMMS director, scientists travel to the remote Southern Ocean to study cloud formation

In January month, an international team of scientists headed to the remote Southern Ocean for six weeks to tackle one of the region’s many persistent mysteries: its clouds.

What they discover will be used to improve climate models, which routinely underestimate the amount of solar radiation reflected back into space by clouds in the region. Accurately simulating the amount of radiation that is absorbed or reflected on Earth is key to calculating how much the globe is warming.

The field campaign, called the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study, or SOCRATES, could also help scientists understand the very nature of how clouds interact with aerosols — particles suspended in the atmosphere that can be from either natural or human-made sources. Aerosols can spur cloud formation, change cloud structure, and affect precipitation, all of which affect the amount of solar radiation that is reflected.

Probes during one run, after a penetration through cloud. Ice build-up can be seen on probes. (Photo provided by Greg McFarquhar/CIMMS)

During the mission, which will run from mid-January through February, the scientists will collect data from a bevy of advanced instruments packed onboard an aircraft and a ship, both of which are specially designed for scientific missions.

“SOCRATES will allow for some of the best observations of clouds, aerosols, radiation, and precipitation that have ever been collected over the Southern Ocean,” said Greg McFarquhar, a principal investigator and the director of the University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies. “These data will provide us with critical insight into the physics of cloud formation in the region, information we can use to improve global climate models.”

The U.S. portion of SOCRATES is largely funded by the National Science Foundation.

“The Southern Ocean is famously remote and stormy and it’s hard to imagine a worse place to do a field campaign. But a vast, stormy ocean is a great laboratory for studying clouds, and it’s clear from our models that we have a lot to learn about them,” said Eric DeWeaver, program director for Climate and Large-Scale Dynamics in NSF’s Geoscience directorate.

“I’m excited about this campaign because I think it will answer some fundamental questions about clouds and their dependence on atmospheric conditions,” DeWeaver said. “We’ll be able to use this information to understand cloud behavior closer to home and how clouds are likely to adjust to changing climatic conditions.”

Critical observing and logistical support for SOCRATES is being provided by the Earth Observing Laboratory at the National Center for Atmospheric Research. Other U.S. principal investigators are based at the University of Washington.

The Australian portion of SOCRATES is largely funded by the country’s government through the Australian Marine National Facility, which is owned and operated by CSIRO.

For more on the project, read AtmosNews from the University Corporation for Atmospheric Research/ National Center for Atmospheric Research.

McFarquhar wrote from the field:

CIMMS Director and SoM professor Greg McFarquhar outside of the G-V aircraft in Hobart. ( Photo provided)

“We are now approaching the mid-point of the Southern Ocean Cloud Radiation Transport Experimental Study, SOCRATES project. We have flown seven research flights representing approximately 50 hours of data during the three weeks we have been in Hobart, Australia. The HIAPER GV aircraft has been able to get all the way to 62 degrees South, allowing us to sample clouds and aerosols within about 400 miles of the Antarctic coast.

An image of large supercooled drizzle drops that researchers measured during SOCRATES at the top of a very thin cloud layer.

We have twice passed over the Australian R/V Investigator and once over Macquarie Island, allowing data to be collected from multiple perspectives. Some of the more notable observations to date, include: the existence of a very clean atmosphere with few large aerosol particles above cloud; the presence of lots of sea-salt 500 feet over the ocean surface, especially when waves are rough; the frequent presence of supercooled water in clouds observed at temperatures as low as -33 C; the multi-layered nature of thin clouds containing supercooled liquid; and the frequent presence of small-scale generating cells at the top of the clouds that we believe to be responsible for the ice particles that we sometimes see interspersed with the supercooled water. It will be interesting to see what the next three weeks bring! ”

*Laura Snider and The University Corporation for Atmospheric Research/National Center for Atmospheric Research contributed to this story. Based on a National Center for Atmospheric Research press release.