Evaluation of the U.S. climate reference network as an operational example of climate monitoring principles

The Principles of Climate Monitoring were centralized into a coherent whole only within the past decade (National Research Council, 1999). Prior to this statement of principles, establishment of a national network for long-term climate monitoring begun in 1948 had not been successful due to a lack of a central mission statement, as well as a lack of a sustained calibration and periodic maintenance program. Without a central mission statement or positive external science underwriting NOAA did not perceive a priority need for a climate network that met the data precision and data completeness requirements of climate scientists.

The Climate Principles against which the CRN Team members measure the effectiveness and satisfaction of the CRN technology to operational principles are:

1. Control & Management Network Changes and Evolutions 2. Parallel Testing and Overlapping Operations 3. Complete Metadata and Annual Metadata Updates 4. Maintaining the Highest Data Quality, Homogeneity, and Continuity 5. Integration of Climate Data into Environmental Assessments 6. Incorporating Historical Values of Homogeneous Observing Systems 7. Inclusion of Complementary Data 8. Maintaining Climate Monitoring Requirements as Network Drivers 9. Continuity of Research To Operations through Network Lifecycle 10. Data and Metadata Access Maintained for All Data User Communities.

In 1999, joint planning for the U.S. Climate Network (USCRN) began among the National Climatic Data Center (NCDC), State Climate Offices, and the Regional Climate Centers of NOAA. The USCRN vision was a scientifically conservative network of 250 station pairs (500 stations total). Budget pragmatism reduced the network to 300 stations, then to 175, and finally to the present planned level of about 110 Stations in the Lower 48 States of the USA. Some additional stations are provided by some States and institutions to densify the network in some areas. At this time 74 CRN stations are in operation.