The NISAR mission has to meet numerous science requirements set by NASA and ISRO. These requirements include global coverage of land where biomass (organic matter) exists, nearly full coverage of all land surface properties, sea ice at both poles and mountain glaciers, and frequent coverage of land areas that are deforming rapidly (earthquake faults, volcanic activity, landslide prone areas, etc.).
NISAR’s L-band and S-band instruments permit many different radar observation modes. The NISAR Science Team has identified which mode will work best for each type of desired observation of land and ice areas across the globe. For a discussion of the SAR polarization modes detailed in the following diagrams, visit the SAR page on this site.
The Observation Plan
Because of the broad science goals of the mission, and the wide variety of radar modes that could be employed over any given area, there is a great potential for complexity in the observation plan. The NISAR science team asked users in each of the three main disciplines that NISAR serves — solid Earth, cryosphere and ecosystems — to create a set of geographic science targets and observational radar modes to optimize their science. The science team then combined these lists, eliminating observational conflicts to produce a simplified target strategy.
The target strategy assigns a single radar mode to a given area on Earth. Where target areas overlap, the modes are compatible so that no science discipline loses information. The specific modes assigned to these geographic targets are shown in the combined mode tables below.
This set of global target types and associated radar modes will provide each of the individual disciplines the data they need for their science. The observation plan calls for nearly continuous global coverage over land and ice.
India has planned specific radar modes to fulfill ISRO’s science requirements for the mission. For the rest of the globe, the most inclusive radar mode was chosen where conflicting science discipline needs were identified. The east coast of Antarctica has been singled out for categorization of sea ice type beyond the basic sea ice data that will be taken over the surrounding Southern Ocean (light pink). Most of the world’s landmass will be observed in the “Background Land” mode (bright green), except for North America, which will be observed with more detail.
As NISAR will be only left-looking – a change in observation tactics since the early planning stages – the mission will rely on data from the international constellation of SAR satellites to supplement its coverage around the Arctic pole.