• Network weaknesses:

o Uneven exposures; many are not well-maintained.

o Dependence on schedules for volunteer observers.

o Slow entry of data from many stations into national archives.

o Data subject to observational methodology; not always documented.

o Manual measurements; not automated and not hourly.

The COOP network has long served as the main climate observation network in the U.S. Readings are usually made by volunteers using equipment supplied, installed, and maintained by the federal government. The observer in effect acts as a host for the data-gathering activities and supplies the labor; this is truly a “cooperative” effort. The SAO sites often are considered to be part of the cooperative network as well if they collect the previously mentioned types of weather/climate observations. Typical observation days are morning to morning, evening to evening, or midnight to midnight. By convention, observations are ascribed to the date the instrument was reset at the end of the observational period. For this reason, midnight observations represent the end of a day. The Historical Climate Network is a subset of the cooperative network but contains longer and more complete records.

G.7. Citizen Weather Observer Program (CWOP)

• Purpose of network: collect observations from private citizens and make these data available for homeland security and other weather applications, providing constant feedback to the observers to maintain high data quality.
• Primary management agency: NOAA MADIS program.
• Data Website: http://www.wxqa.com.
• Measured weather/climate elements:

o Air temperature.

o Dew point temperature.

o Precipitation.

o Wind speed and direction.

o Barometric pressure.

• Sampling frequency: 15 minutes or less.
• Reporting frequency: 15 minutes.
• Estimated station cost: unknown.
• Network strengths:

o Active partnership between public agencies and private citizens.

o Large number of participant sites.

o Regular communications between data providers and users, encouraging higher data quality.

• Network weaknesses:

o Variable instrumentation platforms.

o Metadata are sometimes limited.