A Composite Study of SAR Wind Observations in Southeast Alaska

Synthetic aperture radar (SAR) wind observations from 2000 to 2005 are sorted and compiled into a set of composites representing common surface flow regimes for the inner channels of Southeast Alaska and the outer coastal waters. The terrain of the region consists of an archipelago of mountainous islands that define deep ocean channels or fjords and constrain the wind from achieving geostrophic balance. This results in extensive gap directed flow parallel to the orientation of each channel. Traditional surface based observations are too widely dispersed to diagnose the mesoscale impacts of terrain on these winds, however high resolution SAR imagery offers a detailed look at complex air flow interactions in these gaps. Since infrequent availability and high latency make it difficult to use these data in real time, this study utilizes composites to identify critical exposures, determine common characteristics, and develop a wind climatology that ultimately can be used to improve the wind forecast.