Investigating the Use and Integration of Synthetic Aperture Radar (SAR) Imagery in the Damage Survey Process within the NOAA/NWS Damage Assessment Toolkit (DAT)

NASA’s Short-term Prediction Research and Transition (SPoRT) Center has been working with the NWS to integrate polar-orbiting satellite imagery/derived products into the Damage Assessment Toolkit (DAT) to assist in damage detection after a severe weather event. For the last three years, working with MODIS, VIIRS, Landsat imagers, and leveraging a partnership with the USGS’s Hazard Data Distribution System to access high-resolution commercial satellites such as Digital Globe Worldview has resulted in the identification and refinement of multiple tornado damage swaths across the central and southern United States. One drawback of using optical imagery is the presence of clouds during and after storm event. As clouds block the view of the surface, image collection can be delayed until a clear scene can be obtained. This is further complicated by the longer repeat times some satellites may have over an area of interest, causing additional delays in obtaining useful imagery. Recently, agreements with the European Space Agency (ESA) have provided routine and free access to Sentinel satellite imagery, including the Synthetic Aperture Radar (SAR) instrument on the Sentinel 1-A/B satellites. The use of SAR data to help detect/locate storm damage is desirable as SAR data is collected both day and night and can “see” through any clouds that may be present. In partnership with NASA’s SAR Distributed Active Archive Center (DAAC) located at the Alaska Satellite Facility and the University of Alaska Fairbanks (UAF), SPoRT has been developing tools to help forecasters use SAR products after severe weather events. These products are then made available to the DAT for use during the survey process in conjunction with optical imagery to locate storm damage.

This presentation will discuss how SAR data from the Sentinel 1A/B satellites are processed and developed into products through the collaborations of SPoRT and ASF/UAF. Examples from the hail cases from June and July 2017 over South Dakota and Iowa and the Clear Lake, WI EF-3 tornado will be presented to highlight both the strengths and weaknesses of SAR imagery and how it integrates and compliments more traditional optical imagery collected post-event.