U.S. Climate Reference Network, Part 3: Station Selection Criteria and Station Siting Standards

The U.S. Climate Reference Network (CRN) is being created to meet the challenge of improving the monitoring of climate and the detection of climate change, and to place current and future climate anomalies into historical perspective. That is, the scientific objective of the CRN is improved quantification and detection of climatic change and placement of current/future climatic anomalies and extreme events into historical perspective. The fundamental purpose of the network is to provide homogeneous data sets of air temperature and precipitation that can be used to analyze climate variations and climate change on decade to century time--scales. Station selection criteria have been developed to ensure the stations will be located to represent the regional climate and minimize local biases. Another criterion is data continuity. Thus CRN stations also will be located near to or co-located with existing stations that have been carefully analyzed for long-term homogeneity. Rigorous transfer functions will be developed relating the data from the new instrumentation to data from the existing instrumentation. In this paper, we will discuss station selection criteria and the methods for creating long-term homogeneous time series of temperature and precipitation.