U.S. Climate Reference Network (USCRN): Applications of High Temporal Resolution Fan-Aspirated Temperature Observations

The U.S. Climate Reference Network (USCRN) is a sparsely distributed set of high quality climate observing systems located in the conterminous U.S., Hawaii, and Alaska. USCRN pursues the vision of measuring climate change with instrumentation and methods adhering to the NRC and GCOS Climate Monitoring Principles. The conterminous U.S. network of 114 stations was completed in 2008, and expansion of the network in Alaska commenced in 2009. Triplicate measurements of temperature with well shielded and ventilated platinum resistance thermometers calibrated using National Institute of Standards and Technology traceable standards yield extremely accurate temperature observations in pristine environments. The USCRN is successfully pursing its primary mission of measuring climate change and now provides independent verification of the U.S. temperature record from 2004 onward.

USCRN also has many attributes that provide a strong basis for the development of climate applications. Temperature data are available at 5-minute temporal resolution in the air at 1.5 m above the ground, at the surface, and 5-cm below the surface. Air temperatures are fan aspirated, giving a truer sampling of atmospheric extremes than naturally aspirated systems. This combination of high temporal resolution and high accuracy allows for potentially improved evaluation of many temperature statistics needed for climate applications, including maximum and minimum, daily range, and degree days. The counts of exceedences of extreme threshold temperatures over time will also be applied to understanding useful climate relationships. Overall, USCRN temperature measurements demonstrate many useful advances in applied climatology.