Using SAR Winds to Evaluate Synoptic and Mesoscale Features in Forecast Operations

A national project has been established to evaluate and plan for possible future adoption of synthetic aperture radar (SAR) derived winds for use on an operational basis by the Meteorological Service of Canada (MSC). A large number of SAR wind image datasets is being obtained for forecasters in MSC to assess for utility and for marine weather forecasting on a day-to-day basis.

MSC's marine forecast areas in the Pacific waters are adjacent to the complex terrain and coastlines of British Columbia and subjected to localized terrain-driven winds. In addition sparse weather observations at the coast and offshore decrease the amount of upstream data and the accuracy in placing synoptic-scale and mesoscale meteorological features, thus making marine weather forecasting a challenging task. Many of the details visible in the SAR images do not exist within the observation network, scatterometer data, or in model data. High-resolution, accurate and timely wind fields like the SAR-based winds are desirable to improve marine weather forecast operations.

This work will present several cases over the British Columbia coastal waters of SAR-based winds, and we will compare those winds with Canada's GEM LAM mesoscale model outputs, satellite images and surface observations in different weather patterns. The objective is to demonstrate the utility of the SAR-based winds in marine forecast operations by improving initial analyses, identifying mesoscale and synoptic-scale features, and providing detailed wind patterns adjacent to complex terrain and coastlines. In addition, we will demonstrate that boundary layer processes created through atmosphere-ocean interactions can be seen in the SAR outputs.