U.S. Climate Reference Network Reveals Emerging Capabilities
Not only have the data from the 10-year-old U.S. Climate Reference Network (USCRN) matched up extremely well with the data from the older and more populous U.S. Historical Climatology Network, but new measurements from the USCRN are offering significant capabilities for climate applications and use in climate studies. The triplicate sensors for air temperature, precipitation, and soil-moisture, the latter in place at all 114 USCRN stations since August 2011, have improved quality and continuity of measurements, especially in instances when data would not have been recorded if a site had a malfunctioning single sensor, thus extending the data record. Triplicate sensors also provide verification of data and indicate the possibility of a malfunctioning sensor. To further ensure data accuracy, NCDC scientists developed a new precipitation algorithm that overcame some of the previous limitations in gathering precipitation data, such as sensitivity to instrument noise and evaporation. The new formula better resolves precipitation accumulations at sub-hourly time scales and better assesses overall precipitation totals, especially during colder months.
Soil moisture and relative humidity are not the USCRN’s only new capabilities, however. Recent upgrades to the network’s performance and measurements are of interest to various business sectors, such as agriculture and energy. Since late 2012, most measurements by USCRN have become available at 5-minute resolution, including air temperature, precipitation, 5-centimeter soil moisture/temperature, relative humidity, surface infrared temperature, solar radiation, 1.5-meter wind speed, and wetness. Such temporal resolution permits deeper analysis of the factors that affect both sectors. USCRN soil temperature data during spring have been shown to predict vegetation green-up as seen from satellite-derived Normalized Difference Vegetation Index values at nearby locations. These soil temperatures can also be used to help establish that the soil has reached temperatures cold enough in the fall to safely apply anhydrous ammonia fertilizer. The detailed soil moisture data also are important for determining a climate region’s year-over-year percent differences, with major value to drought monitoring. For the energy sector, the new high temporal resolution 5-minute observations of surface infrared temperature and global solar radiation enhance understanding of factors governing heating and cooling demands, supplementing the 5-minute air temperature data already available.
To meet emerging needs, NCDC staff is developing verifiable soil moisture data and is preparing to conduct the first soil moisture field calibration studies in 2013. Team members also are participating in a study of site representativeness in cooperation with U.S. Department of Agriculture, NOAA’s Cooperative Remote Sensing Science and Technology Center, the Cooperative Institute for Climate and Satellites–Asheville, and National Aeronautics and Space Administration (NASA). Future work includes studying a new surface infrared temperature sensor from NASA that is expected to provide better accuracy. The team also will continue to collaborate with partner organizations on surface infrared temperature studies to produce long-term datasets.
Recently, USCRN team members authored several scientific papers about the achievements of the USCRN. They are:
- “U.S. Climate Reference Network after one decade of operations: status and assessment.” Accepted for publication in Bull. Amer. Meteor. Soc., doi:10.1175/BAMS-D-12-0017
- “U.S. Climate Reference Network Soil Moisture and Temperature Observations.” Accepted for publication in J. Hydrometeorol., doi:10.1175/JHM-D-12-0146.1