Special Session: Sustained Surface Meteorological Networks to Monitor Climate Variability and Change

Air temperature is a critical variable in the US Climate Reference Networks (USCRN). The USCRN air temperature measurement consists of an aspirated radiation shield and a platinum resistance thermometer (PRT). To detect the air temperature signal, the air temperature sensor must be in equilibrium with the air sensor’s physical body, which is achieved through complete coupling between the atmosphere and the temperature sensor. The air temperature measurement errors have two components: electrical-induced error from the electrical components and circuitry in the measurement system (including sensor’s error and data acquisition error) and microclimate-induced error caused by incomplete coupling between the atmosphere and the sensor’s body (including radiative error and errors related to the ventilation rate). Both errors are equally important for the air temperature data of high quality and fidelity. In this study, we explore the uncertainty of air temperature measurements in the USCRN based on the electrical analysis and yearlong field observations taken in Lincoln, NE. The electrical analysis is based on the measurement process implemented through the sensor and data logger. The yearlong observations are analyzed by an inter comparison with two precision aspirated air temperature systems: R. M. Young air temperature system (RMY) and Precision Meteorological Thermometer system (PMT), in which the observations were taken during 2002 and 2003. The results will illustrate the uncertainty of the USCRN air temperature system.