Photosynthetically Active Radiation (quantum line) algorithm updates
January 8, 2024
Photosynthetically Active Radiation (quantum line), DP1.00066.001, has been reprocessed using NEON’s new instrument processing pipeline. NEON is very excited to announce the debut of the new processing pipeline; please stay tuned for more information! All provisional data have been updated, and data for all time and all sites will be updated in RELEASE-2024 (expected to be issued in late January 2024).
The main differences between previous and newly published data are the use of different formulations for computing the skewness and kurtosis statistics (data columns “linePARSkewness” and “linePARKurtosis”, respectively). Previously, these statistics were computed with the Apache Commons Mathematics Library version 3.6.1, which uses special unbiased formulations and not those described in the Algorithm Theoretical Basis Document (ATBD), which cites the standard formulations. The ATBD is available on the data product landing page and is included in each download package if selected. Differences in data values between previous and reprocessed data for the skewness statistic are typically < 1% for 30-min averages and <10% for 1-min averages. Differences for the kurtosis statistic are much larger, as the previous version reported excess kurtosis which subtracts a value of three so that a normal distribution is equal to zero. Thus, new values for kurtosis are typically greater by 3 ± 1% for 30-min averages and 3 ± 10% for 1-min averages.
Other changes are minor, including:
Slight increase in data coverage for various sites and time periods
Quality metrics (expanded download package) are now reported as decimal values and no longer rounded to the nearest integer.
Quality metrics indicating the use of a valid sensor calibration (“validCalPassQM”, “validCalFailQM”, and “validCalNAQM” columns) are now populated in the expanded download package. See the variables file included in the download package for full descriptions of these metrics. Note that these are informational quality metrics and do not impact the computation of the final quality flag.
The number of points in the averaging interval (“linePARNumPts” column) during periods of missing data are now populated with zero (0) instead of empty.
All code used to generate the Photosynthetically Active Radiation (quantum line) data product is open-source and available in the NEONScience/NEON-IS-data-processing Github repository. For questions or more information please Contact Us. Select DP1.00066.001 in the data product dropdown list.
