Using ARM arctic data, Adele Igel is developing high-resolution models to see how aerosols might be linked to cloud dissipation

Adele Igel, an atmospheric scientist at the University of California, Davis, is midway through a three-year project investigating mixed-phase arctic clouds―the kind that contain both ice crystals and liquid cloud droplets.

The work is informed by ground-based observations from the North Slope of Alaska (NSA) atmospheric observatory, operated by the Atmospheric Radiation Measurement (ARM) user facility.

The fate and physics of mixed-phase arctic clouds are important. They persist for days or weeks, and they influence the surface energy budget. Such mixed-phase arctic clouds have profound implications for seasonal ice melt and other phenomena affecting earth systems.

In pursuit of high-resolution models, Igel and her research group are looking at how such clouds dissipate. Specifically, they are looking at how dissipation is linked to surface aerosol concentrations. (Aerosols—ultrafine liquid and solid particles suspended in the air—influence cloud formation, precipitation, and surface energy budgets.)

“From a climate standpoint, we care a lot about whether these low-level clouds are present or not,” says Igel. “They influence whether ice is growing or melting.”

The Igel group is exploring what aerosol populations look like above and below mixed-phase arctic clouds. So far, little is known about how the properties of aerosols vary with height in polar regions.

The researchers use NSA data to identify cases where aerosols may have influenced cloud dissipation. Measurements from Raman lidar are the key. These ground-based laser remote-sensing instruments―very much like radar but based on electromagnetic pulses at much shorter wavelengths―deliver data on aerosols, cloud optical properties, and water-vapor mixing ratios.

Read a full scientist profile of Igel on the Atmospheric System Research (ASR) website.