New ground estimation method applied to GEDI waveforms in Japanese forests
Abstract
GEDI is a vegetation lidar mission on the International Space Station (ISS) to observe Earth's forests and terrain at 1064 nm wavelength, with L1B-L2B products available from April 17, 2019.
GEDI has been observing Earth's forests, including Japan, along the International Space Station (ISS) orbit (inclination: 51.6 degrees, solar asynchronous, 400 km altitude). Japan's forests have a rich diversity of vegetation from sub-arctic to sub-tropical forests, and there is a great variability in canopy cover and topographical conditions. Meanwhile, JAXA is planning a LIDAR mission installed ISS (MOLI; Multi-footprint Observation Lidar and Imager), similar to GEDI. To develop an algorithm to extract elevation and above ground biomass (AGB) from the MOLI footprint (Φ25 m) under various conditions, we collected Airborne Lidar Scan (ALS) data for the same Japanese locations observed by GEDI and compared them to its LIDAR waveforms. We also conducted a field survey at a satellite observation validation site covered by coniferous forest (Larix kaempferi, N35 54 14.9, E138 19 55.2) where GEDI observed June 2019. Comparison of the validation data with the GEDI product confirmed that the Relative Height (RH) as defined in GEDI is different from the definition used in ICESat/GLAS, as it is calculated as a percentage of the total area from 'botloc' to 'toploc' of the waveform, and therefore 'RH100' is an overestimate of the tree height derived from the ALS data and field survey results. Therefore, we developed a method to more accurately estimate the surface signal position from the large footprint lidar waveform and applied it to the observed GEDI data to directly estimate the canopy height from the waveform. In this presentation, we report the newly developed method for estimating surface position and the results of applying the method to the GEDI observed waveforms. We also show the relationship between the newly recalculated RH index and tree height and above-ground biomass (AGB) at the footprint level.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB021.0005M
- Keywords:
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- 0410 Biodiversity;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCES;
- 0480 Remote sensing;
- BIOGEOSCIENCES