Resolved: Spurious trace precipitation in Primary Precipitation data product

A long-standing issue with NEON's weighing gauge precipitation sensors was frequent spurious measurements of trace precipitation. This issue is resolved with the publication of a new data product, DP1.00044.001: Precipitation – weighing gauge.

Precipitation measurements from NEON’s weighing gauge sensors were included in DP1.00006.001: Precipitation along with precipitation measurements collected by secondary and throughfall tipping buckets, which were unaffected. Data from the weighing gauges were published with "PRIPRE" in the file name. A new processing algorithm was developed by NEON scientists to detect and remove spurious precipitation from the output of the weighing gauge sensors. The new algorithm coincides with splitting NEON’s precipitation measurements into three different data products. See data notification: Precipitation (DP1.00006.001) to be split into three Data Products. Primary Precipitation is now referred to as Precipitation – weighing gauge, data product number DP1.00044.001, and published with “WEIPRE” in the file name.

In the original algorithm, sums of spurious precipitation ranged from < 0.05 mm/day to >0.5 mm/day, with higher sums generally corresponding to sites and time periods of greater evaporative demand. The underlying cause of the spurious trace precipitation was sensor noise and susceptibility to environmental variation. The new algorithm used in DP1.00044.001 is designed to robustly detect precipitation events within the background of this noise. Because of the additional uncertainty imposed by the sensor noise, the new algorithm reports hourly and daily precipitation totals along with their uncertainty, as opposed to the 5-min and 30-min totals produced by the previous algorithm.

In the coming days, the PRIPRE tables will be removed from DP1.00006.001: Precipitation, as well as the precipitation tables in DP4.00001.001: Summary Weather Statistics. Precipitation data sourced from the new DP1.00044.001 data product will be added back to DP4.00001.001 in 2025. Another data notification will be issued when this occurs, or a status update will be provided by June 1, 2025, whichever is sooner.

NEON is also working to replace the now obsolete Belfort AEPG 600M weighing gauge precipitation sensor with a new weighing gauge. These sensors will be installed in tandem at all sites and the new sensor and algorithm will result in a revision of the data product to DP1.00044.002. This is expected to begin in mid-2025 and continue over the course of one year.

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