NASA's Surface Topography and Vegetation Study and the QUAKES-I/SAR-Fusion instruments: Mapping our Changing Earth in 3D

In 2020 NASA convened a Surface Topography and Vegetation (STV) Study in response to the 2017 Earth Science Decadal Survey, which recommended STV as a targeted observable requiring further development prior to becoming a mission. The study team addressed several science disciplines, of which vegetation structure was one, and radar, lidar, and stereophotogrammetry techniques for observing vegetation structure. The team developed preliminary science and applications traceability matrices (SATM) for each discipline and combined them into a single SATM the would meet many of the needs of each discipline. The team also identified measurement gaps, of which vertical accuracy, coverage, and rate of change were the most prominent. From an observing system a baseline global map of topography and meter-scale vegetation structure is needed with more targeted repeated measurements in order to capture processes. In 2022 NASA selected team members for a follow-on three-year study with targeted science and technology maturation activities. QUAKES-I/SAR-Fusion is an airborne stereophotogrammetric visible and SWIR instrument being further developed. QUAKES-I is an array of 8 cameras that flies in the nadir port of NASA's Gulfstream V aircraft. It produces a 12 km wide swath with 80 cm ground sample distance, capable of observing tree structure of conifer forest. The instrument flies at 12.5 km and can cover 4500 km in a 5 hour flight. SAR-fusion consists of two visible cameras and two SWIR cameras that look out the left side of a Gulfstream aircraft and are designed to fly concurrently with UAVSAR. The pairs of visible and SWIR cameras produce topography at about 2 m and 9 m ground sample distance respectively with higher resolution in the near-range. We will show results of the eastern Sierra region in June 2021 and the Caldor fire near Lake Tahoe in August 2021.