NSIDC’s Cryosphere Seminar “Interactions between the polar atmosphere and cryosphere: Observations and modeling” by Dr. John Cassano, Lead Scientist at the National Snow and Ice Data Center and CIRES Fellow

Coupling between the atmosphere and the surface is a critical aspect of the climate system. In the polar regions the atmosphere interacts with sea ice, ice sheet, ocean and land surfaces. The Cassano research group studies these interactions by conducting observational field campaigns, through analysis of atmospheric reanalysis and model datasets and by developing and applying regional climate models.

The atmospheric boundary layer modulates the exchange of heat, moisture, momentum and other properties between the atmosphere and the surface. We use a combination of automatic weather station (AWS), unmanned aerial systems (UAS) and other in-situ observations to study the polar atmospheric boundary layer. Examples from our work using data from a “tall tower” AWS and eight polar UAS campaigns will be presented. The UAS campaigns have been conducted throughout the annual cycle over ice sheet, sea ice and bare ground locations in the Antarctic from 2009 to 2017, and in the central Arctic Ocean as part of the MOSAiC (Multidisciplinary drifting Observations for the Study of Arctic Climate) expedition in 2020. Analysis of these data offers insights into the processes that control the thermodynamic state of the lower atmosphere and how the atmosphere interacts with the ice surface. These data also allow us to evaluate the ability of weather and climate models to reproduce observed boundary layer features and processes. 

Our modeling work has focused on the development and application of the Regional Arctic System Model (RASM). RASM is a fully coupled atmosphere – sea ice – ocean – land model. RASM, as well as atmospheric reanalysis and CMIP6 model data, are being used to study the interactions between cyclones and Arctic sea ice. RASM is also being used to study decadal predictability in the Arctic. Examples from both of these efforts will be shared during the presentation.

Dr. John Cassano is a Fellow at the Cooperative Institute for Research in Environmental Sciences, Lead Scientist at the National Snow and Ice Data Center, and Professor in the Department of Atmospheric and Oceanic Sciences at the University of Colorado, Boulder