AVUELO

Airborne Validation Unified Experiment Land to Ocean (AVUELO)

The Campaign

AVUELO is a NASA project that aims to advance the validation and calibration of spaceborne imaging spectroscopy (hyperspectral) data for tropical ecosystems by combining airborne imaging spectroscopy for terrestrial and marine sites in Panama and Costa Rica with contemporaneous field measurements and data collected in February 2025.  This campaign was led and supported by NASA and the Smithsonian Tropical Research Institute (STRI) in Panama, with additional major contributions from other scientists and institutions.

NASA’s Airborne Visible-Infrared Imaging Spectrometer 3 (AVIRIS-3) was deployed on a King Air aircraft to collect hyperspectral imagery between February 6 and February 28, 2025. Terrestrial collections in Panama encompassed many intensively studied sites having a wide variation in soil type, geology, rainfall, and vegetation type. These included managed landscapes, secondary forests of varying ages, and old-growth forests in lowland, montane, and coastal habitats (e.g. mangroves). All areas were collected at 3 m spatial resolution, with intensively studied focal areas of particular interest collected at 1 m resolution. In Costa Rica, AVUELO focused on Rincon de la Vieja volcano to assess differences in vegetation growth due to natural CO2 enhancements. It also collected data over coastal waters off the Pacific to support calibration and validation of PACE, which is a hyperspectral satellite sensor focused partly on oceanic observations.

Associated terrestrial field work focused on acquiring data on the traits and taxonomic identity of canopy plant species captured in the airborne imagery.  An intensive program of canopy leaf collections took place close in time to the overflights. Over 900 samples of over 400 plant species were collected in central Panama. Reflectance spectra were measured on the collected samples, which were all identified to species by expert botanists. Currently leaf functional trait measurements are underway. Ongoing field work includes mapping crowns over >150 ha of mapped forest plots with high spatial precision, to enable linkage of pixels in the airborne data to species identity of canopy trees and lianas.

Stats – Terrestrial airborne campaign in Panama:

• Estimated total of 64 flight hours and approximately 20 terabytes of AVIRIS data collected.
• Acquired 3-meter airborne imagery over Smithsonian sites near the Panama Canal in early, mid and late February.
• Acquired 1-meter imagery on a single date for intensively studied focal sites in Panama:  Barro Colorado Island, Agua Salud, Parque Metropolitano canopy crane, San Lorenzo canopy crane, Parque Summit, and the Gigante fertilization experiment.
• Acquired one-time 3-m imagery data over additional sites of interests, including mangroves (blue carbon sites), montane forests, reforestation areas, agricultural sites, a world heritage site (Coiba Island), and more. 
• Acquired repeat airborne data over methane sources, including Gatun Lake and a large landfill near Panama City.

Stats – Terrestrial ground campaign in Panama:

• Completed 28 days of in situ terrestrial collections.
• Collected 941 plant samples from 457+ species—including 76+ species of lianas—across 304 genera and 95 families.
• Measured reflectance spectral measurements of all canopy leaves, and absorbance spectra of a subset of leaves. 
• Canopy leaf traits:  Leaf water content and leaf mass per area (LMA) measured on fresh leaves of all samples.  Measurements of leaf shape and venation and stomatal characteristics are in progress on the collected material or scans. Planned leaf chemical analyses include elemental composition, pigments, and carbohydrates. 

Stats – Marine campaign in Panama and Costa Rica

• Acquired data over coastal areas in support of PACE cal/val.
• Completed 4 days of coastal collections.
• Collected phytoplankton net samples and niskin bottle samples (HPLC, chlorophyll, CDOM, nutrients, bacteria) across 23 stations.
• Spectral measurements continuously gathered along boat transects.

Project Leads