If you happen to be at a NEON field site during the peak of the growing season this year, look up. There’s a good chance you’ll see one of the NEON Airborne Observation Platforms (AOPs) flying overhead.
These light aircraft are equipped with a payload of sensors—including an imaging spectrometer, high-resolution camera and a full waveform and discrete LiDAR—to gather remote sensing data. Their annual runs over NEON field sites are helping scientists build a picture of landscape-scale changes in vegetation, land use and topography over time.
While preliminary data collection started in 2013, 2018 marks the first year of full operations for the AOP program. In 2017, using two AOPs, the team collected baseline data over 17 of the 20 NEON domains, covering field sites across the continental United States and Alaska. Starting this year, they will begin following a standard schedule of collecting data from each site on a rotating basis for the duration of the NEON project. Under the current plan, data will be collected for sites in the continental U.S. and Alaska three years out of every five, and in Puerto Rico and Hawaii every five years.
This year’s data collection schedule is planned to take the AOPs to 14 of the 20 NEON domains, including their first survey of the Guanica (GUAN) field site in Puerto Rico. The annual flyovers are scheduled during “peak greenness” for each domain. The 2018 data collection season starts in March with the first flight over the San Joaquin Experimental Range (SJER) in California (D17: Pacific Southwest). The planes will follow peak greenness cycles across Alaska, the lower 48 states and Puerto Rico, with the final run taking place in Florida in September.
Collection of AOP data is synchronized with data collected on the ground at each site. This allows scientists to develop a more comprehensive picture of how different observations scale and how measurements taken from airborne remote sensing instruments correlate with observations made on the ground.
Measurements taken from the AOPs include a range of physical, biological and biochemical data available both as flightlines and mosaics, including:
- Topography (elevation, slope and aspect)
- Canopy chemistry (lignin, nitrogen, water content, xanthophyll cycle)
- Ecosystem structure (canopy height and Leaf Area Index (LAI)
- Total biomass maps and vegetation indices
- High-resolution orthorectified camera imagery
NEON airborne remote sensing fills a critical hole in ecological data collection. Standardized, regular airborne data collection over the NEON field sites will allow scientists to monitor changes in vegetation patterns and canopy chemistry on a continental scale over an extended time period. These data will provide new insights into how invasive species are spreading over time and how changes in climate and land use impact forest health and their ability to sequester carbon.
NEON remote sensing data, along with tower sensors, soil sensors and observational field sampling, are freely available on the NEON data portal.
The data are already being used by scientists for a number of projects. A team led by Dr. Phil Townsend, an ecologist out of the University of Wisconsin, is using the data to build a spectral library of vegetation types that links physical and biochemical traits to spectral data. This will enable scientists to classify and map plant species using remote sensing data. At the Smithsonian Environmental Research Center (SERC), Dr. Jess Parker, a forest ecologist, plans to incorporate AOP data into his studies of tree growth and the exchange of carbon, radiation and moisture between forests and the atmosphere.
The airborne remote sensing team is working closely with the science community to optimize data collection for the needs of researchers. Two NEON Technical Working Groups (TWGs) have been formed to guide further data collection efforts, one on airborne sampling design and one on LiDAR. These advisory groups, along with additional discussions with researchers using NEON remote sensing data, will help refine data collection protocols and guide future decisions for expanded data collection or new instrumentation.
Learn more about NEON airborne remote sensing data, including the proposed 2018 flight plan and available data products from 2017 and earlier.