ICESat-2 Comparison with Field Height in Brazilian Pastures

ICESat-2 is a satellite lidar system launched in 2018 that has global coverage of terrestrial and ice-covered regions. This satellite provides a potential source of information regarding vegetation height and structure, but has not previously been applied specifically to pasture areas. Here we present results from fieldwork in the Rio Vermelho watershed in Goiás, showing the applicability of ICESat-2 vegetation height and structure metrics to pastures. We analyze metrics calculated from the ATL08 product, which is more readily applied at the large scale, and the ATL03 product, which allows for improved filtering of ICESat-2 measurements. We also test filters based on season, time of day, and laser strength to determine best practices when applying ATL08. We find that median height is a metric appropriate for Brazilian pastures, with an RMSE of 3.3 m when considering 20 m segments and 2.4 m for 100 m segments. Using the filters available in ATL03, the RMSE for 20 m segments decreases to 2.5 m.