Coastal wetlands, especially salt marshes, store vast amounts of terrestrial carbon both above and belowground. Conserving and restoring them can help sequester such carbon, but sea-level rise and other anthropogenic threats risk liberating these long-term carbon stores to the atmosphere where they would contribute to climate change.
Gwen Miller, a Ph.D. Student at the University of South Carolina, collaborated at two coastal sites (North Inlet in Georgetown, SC, and the Plum Island Ecosystems Long-Term Ecological Reserve, MA) to assess the ability of Planet’s Dove imagery to estimate aboveground vegetation biomass. Miller and colleagues intersected field data on biomass, with biomass estimates from Planet data based on a series of spectral vegetation indices, and found that ~55% of variation (Willmott’s index of agreement) in aboveground biomass could be explained by Planet data. They speculated that improved atmospheric correction could lead to further improvement in model performance.
Miller et al. write: “The advantage of using Planet’s data is its high spatial resolution and repeat time, which allows for analysis of biomass distribution and temporal change on a finer scale. The finer scale analysis is particularly useful for land and coastal managers interested in assessing marsh health. Furthermore, the frequent repeat time of Planet’s satellite series provides more usable coastal data; analysis within a salt marsh requires imagery collected during low tide, and clouds often cover the coast during the summer making it difficult to find suitable data.”
The entire study, which was published open access, can be viewed at the journal Remote Sensing.