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As part of the upcoming 2025 NEON Annual Release, AOP is in the process of updating data products with known quality issues, summarized in Table 1 and Table 2 below. We recommend holding off on downloading the AOP data products listed in Table 1 between January 10, 2025 and January 31, 2025, when RELEASE-2025 becomes available.

The majority of AOP data quality issues fall into one of two categories, listed below. Please refer to the data product issue logs on the Data Portal for additional details.

1. Mis-classified point clouds in the discrete lidar data, which resulted in artifacts in all AOP data products: the derived L3 lidar products (all raster models: DTM, DSM, CHM, Slope, and Aspect), as well as orthorectification issues in the RGB camera and reflectance data products, which rely on the DSM generated from the Lidar data. For example, dense atmospheric noise above the canopy would be classified as high vegetation, which presented as erroneously high canopy in the L3 Lidar data products (eg. CHM, DSM). In most cases, these noise issues were typically only present in small and isolated areas.
2. Mis-alignment in the line to line adjustments; a step in the Lidar L1 processing which adjusts adjacent flight lines; this data issue also affected all data products. Starting in 2020, AOP started using the software to perform these flightline adjustments, as it was found to provide better results than the software solution previously used. Some of the earlier (pre-2020) AOP collections were found to have high misalignment between lidar flight-lines, on the order of meters of vertical differences between lines.

In addition to these quality issues, some smaller data updates will be made, including colorizing lidar point clouds and fixing file names that do not follow the standard naming conventions.

 Table 1: Planned AOP data quality updates for RELEASE-2025 that are currently included in RELEASE-2024

 Table 2: Planned AOP data quality updates for RELEASE-2025 that are currently PROVISIONAL

As part of the upcoming Data Release, only discrete lidar data products (, , , ) and camera data products (, ) will be re-processed to correct for the known issues, continue reading for more information about the status of the AOP reflectance data products in 2025.

AOP Reflectance Data Products

As of 2024, NEON has begun to publish bidirectional reflectance data products, which include BRDF and topographic corrections. These corrected L1 reflectance and derived (L2-L3) reflectance data products are now available under a separate revision (.002) for AOP data acquired between 2022-2024. L1 directional reflectance will still be available () in addition to the bidirectional reflectance (). These bidirectional data will be available provisionally in 2025 and will not be included in RELEASE-2025 since they were generated within the past year. Starting in Feb 2025, AOP plans to back-process earlier years of reflectance data (2013-2021) to include the BRDF and topographic corrections; eventually all of the directional reflectance products will be replaced by the bidirectional reflectance data. As part of this planned re-processing effort, any original reflectance data products (.001 revisions) for the sites with known orthorectification data issues will be updated in 2025 and included in RELEASE-2026.

AOP Data Availability in Jan 2025

There will be a ~3 week period between January 10, 2025 and ~January 31, 2025 (when RELEASE-2025 becomes available) where the data availability chart may not reflect the true availability of the products on the portal for the released sites listed in Table 1. Neither the RELEASE-2024 tag nor the DOIs for the released data products listed will be applicable due to the changing content. We recommend holding off on downloading the listed AOP data products during this interim period, or using the NEON Contact Us form to request the status of a given data product, site, and year. The 2025 Release is estimated to be complete by the end of January 2025, and at that time, all AOP data from RELEASE-2024 will be Tombstoned and superseded by RELEASE-2025. For more information on the release process as it pertains to AOP, please refer to the AOP Release Process section of NEON's Data Product Revisions and Releases page.