The University of Arizona

Data Sources and Networks | CLIMAS

Data Sources and Networks

Weather and climate monitoring is accomplished by networks collecting data from a variety of sources, including satellites, thermometers, and rain gages. Stations are located in both rural and urban areas, including areas prone to fire. Many monitoring networks have been collecting data for more than 100 years. Temperature, precipitation, snow depth, and humidity are some of the types of data collected.

Most data is put through a degree of quality control, ranging from adjustments made by the observer to rigorous statistical algorithms. Some stations, however, have little or no quality control. Climate and weather monitoring provides researchers, farmers, ranchers, and businesses with information they need, whether it involves understanding climate change or deciding when to plan crop cycles. Some of the major data collection networks are the Cooperative Observer Program (COOP); Historical Climate Network (HCN); Arizona Meteorological Network (AZMET); Parameter-elevation Regressions on Independent Slopes Model (PRISM); and Remote Automated Weather Stations (RAWS). A brief description of these networks can be found below and is summarized in Figure 3.

Cooperative Observer Program (COOP)

The COOP network began collecting daily measurements of climate data in 1890. The majority of its 12,000 active monitoring stations are operated by volunteers. In the past there have been about 32,000 stations in the U.S. Some of the data provided by the stations include maximum and minimum daily temperatures, temperature at the time of observation, and precipitation and snowfall totals. The COOP network is a significant contributor to efforts to understand climate trends.

Historical Climate Network (HCN)

The HCN has 1,221 stations, making up a smaller subset of the COOP network. These stations have undergone minimal relocations and span 48 U.S. states, with 25 stations in Arizona and 28 in New Mexico. Dating back about 80 years, the HCN stations provide long and complete records where location of the data acquired has remained relatively constant. Like the COOP stations, HCN data include maximum and minimum daily temperatures, temperature at the time of observation, and daily precipitation and snowfall totals. The amount of data quality control sets the HCN apart from the COOP network; data from HCN stations undergoes a more vigorous quality control.

Arizona Meteorological Network (AZMET)

AZMET is a part of the Cooperative Extension at the University of Arizona. The roughly 28 active AZMET stations are located in both rural and urban areas of central and southern Arizona. Weather and climate variables recorded by AZMET stations are used for irrigation management, golf courses, agricultural practices, and researchers, among others. The data includes hourly measurements of air temperature, soil temperature at two depths, precipitation, wind speed and direction, solar radiation, and humidity. These measurements allow AZMET to calculate evapotranspiration and components that characterize plant life cycles. Although AZMET stations are well maintained and the data undergoes moderate quality control, their records are fairly short, spanning only 22 years, which limits their use for deriving long-term climate trends.

New Mexico State University Climate Network

New Mexico State University manages 18 weather stations and grants access to hourly and daily data from these and about 32 other stations around the state. This network was established primarily to  serve agriculture and aid agriculture extension efforts. The data includes precipitation, minimun and maximum temperature, wind speed and direction, solar radiation, and other climate and weather variables.

Remote Automated Weather Stations (RAWS)

This network was developed primarily to aid in the prediction of fire behavior and fuel conditions. These station sites are generally located in remote areas that are most susceptible to fires (i.e. extreme wind and sunlight intensity). Some of the data from RAWS are also used to monitor air quality and for research. Approximately 2,200 RAWS throughout the U.S. record weather conditions every minute to every hour. The data include temperature, precipitation, wind speed and direction, barometric pressure, and relative humidity; some stations also provide the moisture and temperature of fire fuels. Although the RAWS data is free and easy to access, there are some limitations. There is no quality control, many of the stations do not take readings during the winter, and some stations often are moved to a new location, depending on the micro climate of that area. The National Weather Service takes data collected from monitoring stations and incorporates it into models to help forecast weather.

Parameter-elevation Regressions on Independent Slopes Model (PRISM)

PRISM creates virtual data sites in areas where data is limited, essentially narrowing the gaps between established monitoring stations. PRISM uses measurements made at other monitoring stations combined with an observation-based statistical algorithm to generate climate data. This data generation results in a monthly climate record for a 2.5 x 2.5 mile (or four kilometer) grid that covers the continental United States and dates back to 1985 (Figure 2).

Related Links

  1. Cooperative Observer Program: (1) daily data via NCDC; (2) monthly data for New Mexico; (3) monthly data for Arizona
  2. U.S. Historical Climate Network: (1) monthly data via National Climatic Data Center; (2) monthly and daily data via Carbon Dioxide Information Analysis Center
  3. Arizona Meteorological Network
  4. New Mexico Climate Station Data
  5. Remote Automated Weather Stations: (1) via the Western Regional Climate Center; (2) via Forest Service
  6. PRISM: (1) via PRISM Group at Oregon State; (2) via Westmap with a more customizable Web interface