Cooperative Institute for Research in Environmental Sciences

A description of the Ross Ice Shelf air stream (RAS) through the use of self-organizing maps (SOMs)

Seefeldt, M.W., and J.J. Cassano

2012, Journal of Geophysical Research, 117, D9, doi:10.1029/2011JD016857.

The low-level wind field across the Ross Ice Shelf region, Antarctica is studied through the method of self-organizing maps (SOMs). Emphasis is placed on identifying and characterizing the Ross Ice Shelf air stream (RAS). The RAS is a dominant northward stream of air resulting in significant transport of atmospheric mass from the interior of Antarctica. Two SOMs are created for the lowest model level and the 5th lowest model level, from archived real-time numerical weather prediction output. A verification of the SOM for the lowest model level is completed by comparing select nodes to automatic weather station wind rose plots. The lowest model level SOM is dominated by the position of the cyclone in the Ross Sea and the changes in wind speeds on the Antarctic plateau. The 5th lowest model level provides a greater depiction of the RAS. The RAS is found to be present primarily when associated with a cyclone in the Ross Sea. There is a strong seasonality to the RAS with the RAS occurring frequently during the winter months and rarely during the summer months. The structure and position of the RAS is strongly dependent on the position of the Ross Sea cyclone.