The U.S. Climate Reference Network (USCRN) is managed by NOAA’s Air Resources Laboratory (ARL), and the responsibility for the maintenance and engineering for the 139 stations across the conterminous US (114 stations), Alaska (23 stations), and Hawaii (2 stations) lies with ARL’s Atmospheric Turbulence and Diffusion Division (ATDD) in Oak Ridge, TN. The USCRN provides the Nation with a climate-quality benchmark observing system that provides accurate and high-quality meteorological observations and forecasts to assess and adapt to current and potential threats associated with climate variability. Changes in the climate can influence economic prosperity, national security, and human and environmental health.

With respect to maintenance, there are two kinds: (1) Annual Maintenance Visits (AMV); and (2) Unscheduled Maintenance Visits (UMV). During normal times each USCRN station gets a once per year AMV where ATDD engineers and technicians ensure that (a) all sensors are operating within specifications; (b) repairs ranging from swapping out old instrumentation to repairing fencing and ancillary infrastructure from animal or storm damage are made; and (c) new firmware or on-site datalogger software are made. Coincidental with the restrictions imposed by the COVID-19 pandemic, it was required that all full AMVs ceased in March 2020.

Since weather and climate phenomena do not end due to a pandemic, it is important to try and maintain the set of USCRN stations in order to assure that the climate data record is as continuous and high-quality as possible. Fortunately, we have been able to keep the network updated and calibrated via the UMV maintenance option, and as such all USCRN stations are still operating and providing good data that exceeds the system’s performance measure for data receipt at the rate of 98%. While the pandemic continues and field engineers are not able to travel out to the field to maintain the stations, we have been able to keep stations maintained by working with our local site hosts who have been able to assist us with routine maintenance issues; this coupled with ATDD’s ability to make one-day trips from Oak Ridge, TN to sites within a day’s drive using approved NOAA COVID-19 extraordinary travel protocols. Additionally, for harder to reach stations in Alaska, we have a contract engineer who is based in Alaska, and is able to assist us with UMV maintenance visits as well as some limited modified AMVs at 10 stations in Alaska.

The only negative impact to the USCRN network has been in the completion of the full network build-up in Alaska, as such installation visits (which can only occur during the summer building season) require travel which is outside of current NOAA COVID-19 travel protocols. As such, ARL has also had to delay the planning and staging of the installation of 1-2 new stations in Alaska, and will likely see a longer-term delay in the completion of the final 6-7 new stations in ARL’s network in Alaska from 2023 to 2025. While we would like to restart our work in Alaska in the summer of 2021, it is more likely that we will be able to restart the installation of new stations in Alaska during the 2022 summer building season. For more information on USCRN please consult the websites at https://www.ncei.noaa.gov/access/crn and https://www.atdd.noaa.gov/crn.

For any questions related to the USCRN, please contact: Howard J. Diamond, PhD, U.S. Climate Reference Network Program Manager (howard.diamond@noaa.gov)