A satellite diagnostic study of Antarctic fog

The United States Antarctic Program (USAP) is the largest scientific research program in the Antarctic and requires a considerable aviation operation. Of the more than 700 flights planned each year, nearly 175 are aborted due to bad weather conditions. Although fog is one of the top three forecast problems related to flights aborted due to weather, it is largely unstudied. This investigation examines fog that affects the important Antarctic research station, McMurdo Station, Antarctica and its nearby airfields. The objective of this research is to acquire an understanding of fog occurrence in the region via satellite analysis.

Recent developments in the last 10 years have added new tools to examine fog occurrence in Antarctica. With the launch of the Earth Observing Satellite Terra in 1999, the depiction of fog and low clouds is possible in the Antarctic using the Moderate-Resolution Imaging Spectroradiometer (MODIS) onboard. A multi-channel fog and low cloud depiction method has been developed using the MODIS satellite observations via principal component analysis. A basic validation was conducted using observations from the University of Wisconsin Automatic Weather Station (AWS) network.

The multi-channel satellite observations indicate that most austral summer fog events are “advective” in nature. This is supported by weather observations from McMurdo Station and nearby airfields where fog occurs at moderate wind speeds, and primarily from the eastward direction. Having identified the source regions of fog and developed a satellite depiction method for fog, forecasters have additional tools for improving the monitoring and forecasting of fog events.