Observational Perspectives from U.S. Climate Reference Network (USCRN) and Cooperative Observer Program (COOP) Network: Temperature and Precipitation Comparison

Leeper, R.D., J. Rennie and M.A. Palecki, 2015: Observational Perspectives from U.S. Climate Reference Network (USCRN) and Cooperative Observer Program (COOP) Network: Temperature and Precipitation Comparison. Journal of Atmospheric and Oceanic Technology, 32. https://doi.org/10.1175/JTECH-D-14-00172.1

The U.S. Cooperative Observer Program (COOP) network was formed in the early 1890s to provide daily observations of temperature and precipitation. However, manual observations from naturally aspirated temperature sensors and unshielded precipitation gauges often led to uncertainties in atmospheric measurements. Advancements in observational technology (ventilated temperature sensors, well-shielded precipitation gauges) and measurement techniques (automation and redundant sensors), which improve observation quality, were adopted by NOAA’s National Climatic Data Center (NCDC) into the establishment of the U.S. Climate Reference Network (USCRN). USCRN was designed to provide high-quality and continuous observations to monitor long-term temperature and precipitation trends, and to provide an independent reference to compare to other networks. The purpose of this study is to evaluate how diverse technological and operational choices between the USCRN and COOP programs impact temperature and precipitation observations. Naturally aspirated COOP sensors generally had warmer (+0.48°C) daily maximum and cooler (−0.36°C) minimum temperatures than USCRN, with considerable variability among stations. For precipitation, COOP reported slightly more precipitation overall (1.5%) with network differences varying seasonally. COOP gauges were sensitive to wind biases (no shielding), which are enhanced over winter when COOP observed (10.7%) less precipitation than USCRN. Conversely, wetting factor and gauge evaporation, which dominate in summer, were sources of bias for USCRN, leading to wetter COOP observations over warmer months. Inconsistencies in COOP observations (e.g., multiday observations, time shifts, recording errors) complicated network comparisons and led to unique bias profiles that evolved over time with changes in instrumentation and primary observer.

Study type: Validation, Inhomogeneities

Inhomogeneities metadata
Study type: Network comparison
Instrument type: Liquid in Glass thermometer, Thermistor
Screen type (including Wild screen): Multiplate screen, Stevenson screen
Screen class (including early screens): Stevenson screen, multiplate
Analyzed: Temperature, Precipitation
Causes: Season, Wind speed, Observer, Temperature, Precipitation intensity, Instrumental error, Ground cover, Snow, Ground albedo,
Additional measurements: Solar radiation, Surface wind speed, Surface infra red temperature, Relative humidity, Soil moisture and temperature at various depths
Observation type: Manual, Automatic
Period: 8 Years
No locations: 12
Temporal resolution: Annual, Monthly, Daily, Hourly
Validation metadata
validation type: Comparison with another data quality

Tags: MMTS