NOTE: The ALTOS campaign has been terminated. For more information, please see the Facility News update from November 3, 2010.

On October 27, the Arctic Lower Troposphere Observed Structure (ALTOS) field campaign began at Oliktok Point on the North Slope of Alaska. This campaign is obtaining measurements of cloud microphysics, radiative energy, and aerosol from the Arctic troposphere using an instrumented tethered balloon in conjunction with remote-sensing instruments on the ground.

The one-month campaign takes place during the fall transition season, when sea ice begins to form and dramatic changes in the atmospheric structure and cloud properties occur. The unique data set resulting from this campaign will support future testing of Arctic cloud processes used in climate models and for testing algorithms used to retrieve these measurements.

Led by Hans Verlinde, ARM’s North Slope of Alaska site scientist, daily operations will use several insulated shelters for the ground instruments, balloon operations, and office space, plus a truck for the cloud radar. When low-level clouds are present, ALTOS instruments will operate continuously for stretches of several hours as weather and personnel considerations permit. The balloon is making ascents through the clouds with instruments that measure cloud microphysical properties, while the ground-based instruments simultaneously collect additional data.