Monitoring Hydro Temporal Variability in Alberta, Canada with Multi-Temporal Sentinel-1 SAR Data

Freely available high temporal and spatial resolution synthetic aperture radar (SAR) satellite data such as Sentinel-1 have made it possible for almost near-real time monitoring of surface water extent. We present a method to track temporal variability in surface water extent, hereafter hydro temporal variability (HTV) in Alberta, Canada. Multi-temporal Sentinel-1-C band SAR data was used to classify each pixel in a pixel stack across time into water or non-water. This dataset can tell the percent of time a given 10 m × 10 m pixel was seen as open water. HTV was then summarized by calculating the percentage of the total pixel stack, which was detected as water. Comparison to the waterbodies in the Government of Alberta Base Features Hydrography Polygon dataset shows that the HTV dataset is able to differentiate between permanent and recurring lakes as well as capture rivers with a width of over 30 m. It is anticipated that the methodology presented here will be further enhanced and refined with imagery available for 2018 and beyond, due to now operational Sentinel-1B satellite and future RADARSAT Constellation Mission (2018), which will both provide improved data opportunities.