Applicability of synthetic aperture radar for investigating river breakup on the Kuparuk River, Northern Alaska

Abstract

A combined use of remote sensing techniques and field measurements is a pragmatic approach to study Arctic hydrology, given the vastness, complexity, and logistical challenges posed by most Arctic watersheds. This study investigates the use of synthetic aperture radar (SAR) to define spring breakup of the Kuparuk River on the North Slope of Alaska. A time series (years 2001-2010) of SAR images was assembled at the river mouth on the Arctic Coastal Plain. A statistical analysis was used and was limited to three variables: image brightness, variance in brightness over the river length, and a rank order analysis accomplished by segmenting the river and ranking segments in order of relative brightness. Variance was the only reliable breakup indicator of the three tested. A shorter one year temporal stack was assembled at the river's headwaters for a visual interpretation, which had limited success. Results from both analyses were calibrated with in-situ stream gauge data. River ice breakup is a highly complex process which may be defined differently by the remote sensing community and hydrologists, due to the sensitive nature of SAR, which may indicate surficial changes on the river before any discharge is recorded.