Integrating GEDI, ICESat-1 and -2 to Characterize Vegetation Structure Dynamics: DOs and DON'Ts

Abstract:

Forests exhibit dynamic responses to natural environmental changes and anthropogenic impacts. Accurate measurements of vegetation structure dynamics are yet missing, preventing a more comprehensive evaluation of their roles in ecosystem services such as carbon stocks and biodiversity conservation. Spaceborne lidar can potentially fill this observational gap and advance our understanding of forest ecology as demonstrated by NASA's ICESat-1 mission deployed between 2003 and 2009. Two following spaceborne lidar missions, ICESat-2 and GEDI, have restored our capacity to measure global vegetation structure since 2018. Similarities of these lidar missions form a basis for complementary observations that can explore vegetation structure dynamics at time scales ranging from seasonal to decadal. However, significant differences of observed vegetation structure can arise given different instrument configurations and varying measurement accuracies. Here we use multiple reference datasets over the U.S., including NASA’s airborne LVIS facility and statewide high-resolution airborne lidar as part of NASA’s carbon monitoring system (CMS), to identify origins of these possible biases. Outcome of the research will provide a general guideline for monitoring vegetation structure dynamics when using these space lidar products together.