We have recently discovered multiple instances where timestamps became out of sync between the Picarro G2131 and L2130 instruments and computers, and what was assigned to the data points upon transmission to NEON Headquarters. This has resulted in offsets ranging from 20 seconds to 12 minutes in data products DP1.00036 Atmospheric CO2 isotopes and DP1.00037 Atmospheric H2O isotopes. Many sites and time periods have been affected, we will update with specific instances by the end of July 2020.
There are two root causes:
- The instrument becomes out of sync with the location controller at the site. This issue has been resolved and is not expected to impact data going forward.
- The instrument becomes out of sync with its computer. When detected, this can be resolved by a hard restart of the instrument. We are working with the manufacturer on further troubleshooting and to find a permanent resolution.
When this problem occurs, it often leads to high variance and offset mean values in reference gas measurements because the averaging window in data processing covers two span gasses.
We are raising the science review flag for the affected time periods and investigating the possibility of data correction. Please use the data portal contact form for further inquiries; select DP1.00036 or DP1.00037 in the Data Product dropdown list and include the term “PRB0040670“ in the body of your request