Bringing SAR capability to a safer ice navigation during Indian Antarctic Expedition in near real-time mode

The present study has been executed for providing sea ice advisory during the 40th Indian Scientific Expedition to Antarctica (ISEA) to carry out a smoother expedition. The near real-time knowledge of sea ice conditions along with safe, optimum and less fuel consumption routes is essential for expedition vessel movement through the Antarctic sea ice regions. The radar can distinguish between more navigable thinner/weaker sea ice and the hazardous, much thicker sea ice along with icebergs to help assure safe navigation in ice-covered regions. In the current study, considering the advantage of spatial and temporal resolutions along with acquisition modes of the Sentinel-1, we have standardized the procedure to find the penetrable passage within the sea ice packs. The pre-processing steps of Sentinel-1 data were performed to generate backscattered products. Further, for intensity images of Interferometric Wide (IW) mode and Extra Wide (EW) mode, the procedure for identification of different types of sea ice and ocean water has been discussed in the paper. Our study also highlights the use of ERA 5 reanalysis data for better interpretation of SAR data due to the presence of the blizzard footprint in the acquired image. And finally, a significantly improved near real-time Sea Ice Advisory (SIA) surrounding two Indian Antarctic Research Stations was produced and utilised to support safer navigation during the 40th ISEA voyage