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The ASOS program is a joint effort of the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the Department of Defense (DOD) that began in the early 1990s. It was designed primarily to support weather forecast activities and aviation operations. ASOS routinely and automatically provides computer-generated voice observations directly to aircraft in the vicinity of airports, using FAA ground-to-air radio. ASOS also transmits a special report when conditions exceed preselected weather element thresholds, e.g., the visibility decreases to less than 3 miles. These messages are also available via a telephone dial-in port.
Up to 12 times per hour, ASOS sites report: air temperature, dew point temperature, wind speed and direction, wind gusts, sea level pressure, altimeter setting, accumulated precipitation, visibility (to at least 10 smi), sky conditions (cloud height and amount (clear, scattered, broken, overcast) up to 12,000 feet), and selected significant remarks including variable cloud height, variable visibility, precipitation beginning/ending times, rapid pressure changes, pressure change tendency, wind shift and peak wind.
The network was first established in 1991, with the network completed in 2004. Currently there are approximately 850 sites across the continental US.
The AWOS units are operated and controlled by the Federal Aviation Administration (FAA), as well as state and local governments and some private agencies. They generally report at 20-minute intervals and do not report special observations for rapidly changing weather conditions. Currently there are approximately 650 sites across the continental United States. There are six standard categories of AWOS depending upon the sensor systems installed:
This network was begun in the early 1980s and has expanded to cover many states in the High Plains region. Air temperature, relative humidity, wind direction and speed, precipitation, solar radiation, soil temperature (4 inches), and estimated potential evapotranspiration. The data is available through the High Plains Regional Climate Center:http://www.hprcc.unl.edu/awdn.php
CoCoRaHS, a non-profit, community-based network of volunteers working together to measure and map precipitation (rain, hail and snow) is based at Colorado State University and was first established in Colorado in 1998. The network has grown to more than 12,500 observers nationwide. It is currently sponsored by NOAA and the National Science Foundation (NSF). Low-cost, 4-inch rain gages are used to provide high quality precipitation data for natural resource, education and research applications. Measurements are generally taken in the morning at 7 a.m. local time. Evapotranspiration measurements are being added to the network. http://www.cocorahs.org/
Observations from Forts and volunteer observers were made during the 1800s. Surgeons in U.S. Army forts recorded daily weather observations starting in the early 1800s; in the mid-1800s, volunteer observer networks were managed by the Smithsonian Institution; later the Signal Corps under the Department of War made observations; finally the network was incorporated into the U.S. Weather Bureau in the U.S. Department of Agriculture, later to become the Department of Commerce NWS Cooperative Network. Data for 450 of the longest-reporting stations were digitized through NOAA's Climate Data Modernization Program. Temperature, precipitation and snow data were quality controlled for 350 of these stations, 326 in the lower 48 states. Data for 39 possible variables at various observing times were digitized. Daily precipitation and maximum and minimum temperatures have been incorporated into the Global Historical Climatology Network (GHCN) database. Pressure data have been incorporated into the 20c Reanalysis Program -v2 and -v3. The data are archived at the Midwestern Regional Climate Center FORTS Early American Weather section.
Near real-time marine (weather and sea state) data from Great Lakes buoys, coastal met stations, airports, and ships are archived at the NOAA Great Lakes Environmental Research Laboratory. The data are transmitted through the NOAAPORT system and are received continuously at NOAA/GLERL via satellite dish. Hourly observations of many variables are archived. Marine observations from the buoys include wind speed, wind gust, wind direction, air temperature, dew point, cloud cover, sea level pressure, water temperature, wave height, and wave period. Locations of buoys in this network are mostly near the coastlines of the Great Lakes with a few buoys located farther from shore.
The Hydrometeorological Automated Data System (HADS) is a real-time data acquisition and data distribution system operated by the NWS Office of Hydrologic Development. The system was developed primarily to support the Flood and Flash Flood Warning programs. The HADS system acquires raw hydrological and meteorological observation messages from Geostationary Operational Environmental Satellites (GOES) Data Collection Platforms (DCPs). The data from approximately 15,000 sites originates from DCPs owned and/or operated by more than 100 cooperators, including the Water Resources Division of the U.S. Geological Survey, the U.S. Army Corps of Engineers, the Tennessee Valley Authority, the Bureau of Land Management, the U.S. Forest Service, the Bureau of Reclamation, NWS, and departments of natural resources from numerous state and local agencies throughout the country. NOAA's National Environmental Satellite, Data Information Service (NESDIS) operates and maintains the GOES Data Collection System (DCS). After downloading, the raw data are translated into Standard Hydrometeorological Exchange Format (SHEF) products. Generally, the data consist primarily of precipitation and River Stage (15, 30 and/or 60 minute, sent from 5-min to 24-hour intervals), with some stations reporting air and water temperature, wind speed and relative humidity. There is no initial quality control of the real-time data. http://www.nws.noaa.gov/oh/hads/
The RAWS network began in the early 1980s in the western states and is operated by the U.S. Forest Service and the Bureau of Land Management, primarily to observe potential fire conditions. The network began to expanded eastward in the late 1990s and currently consists of about 1700 permanent (and several hundred temporary) solar powered units collecting data on an hourly basis: air temperature, relative humidity, wind direction and speed, precipitation, solar radiation, soil temperature, and estimated evapotranspiration. Fuel temperature and moisture measurements are also collected (temperature and relative humidity sensors embedded in a pine dowel placed 6-12 inches above the native fuel bed). Data are sent via satellite to the National Interagency Fire Center. The historical archive of data is maintained at the Western Regional Climate Center. http://www.raws.dri.edu/
SCAN is operated by the USDA National Water and Climate Center in the National Resources and Conservation Service. SCAN was initiated in 1991 with the installation of 21 sites with a goal of establishing a soil climate monitoring program. There are about 165 stations located in the lower 48 states. Sites are located primarily on federal-, state- or university-managed lands. Air temperature, relative humidity, wind direction and speed, barometric pressure, precipitation, solar radiation, soil temperature (2, 4, 8, 20, 40 inches), soil moisture (2, 4, 8, 20, 40 inches) and estimated potential evapotranspiration. Some stations also measure water level, water temperature and quality, and IR-measured soil temperatures. http://www.wcc.nrcs.usda.gov/scan/
The U.S. Cooperative Observer Program is the nation’s oldest currently-existing weather network, established in 1890 under the Weather Bureau in the U.S. Department of Agriculture. It is now operated by the National Weather Service of NOAA which is under the Department of Commerce. Nationwide, there are about 11,000 sites providing daily values of maximum and minimum temperature, precipitation, snowfall and snow depth. http://www.nws.noaa.gov/om/coop/
The System-Wide Monitoring Program (SWMP) was established by NOAA’s National Estuarine Research Reserve System (NERRS) (www.nerrs.noaa.gov) in 1995 to develop quantitative measurements of short-term variability and long-term changes in the water quality, biological systems, and land-use/land-cover characteristics of estuaries and estuarine ecosystems to support effective coastal zone management. Currently, there are 28 Reserves, each with at least four water quality monitoring stations and one station collecting meteorological data. Nutrient data are also collected nominally at one water-quality station and often at several others in the Reserve. Meteorological data are reported at 15-minute intervals and prior to 2007, hourly and daily average data were also reported. The meteorological stations record air temperature, relative humidity, precipitation, barometric pressure, average wind direction and speed, standard deviation of wind direction, maximum wind speed (with time), total photosynthetically active radiation, and total solar radiation. Water quality data include water temperature, depth, specific conductivity, dissolved oxygen, pH, turbidity and nutrients (ammonium, nitrite, nitrate, orthophosphate, and chlorophyll).
The USCRN was established in 2001 by NOAA and continues to be maintained and managed by NOAA. It consists of 106 stations across the continental US, with 6 sites in Alaska and 2 in Hawaii. Air temperature, wind speed and direction, IR-Temperature and solar radiation are averaged every 5 minutes, precipitation is accumulated in 15-minute increments, and data are transmitted hourly. The USCRN network was upgraded between April 2009 and August 2011 to include measurements of relative humidity, as well as soil moisture and soil temperature (except for Torrey, UT which is located on solid rock). At 82 of the sites 2, 4, 8, 20 and 40 inches are instrumented, and at the other 61 sites only the 2 and 4 inch levels are instrumented for soil moisture and temperature due to site limitations. http://www.ncdc.noaa.gov/crn/
RCRN stations are spaced more closely (130 km resolution) than the USCRN stations to provide for the detection of regional climate change signals, and focus solely on temperature and precipitation. The RCRN network currently includes 92 regional stations in the Southwestern U.S. and Alabama. The long-term vision is deployment of sites in each of the nine NOAA climate regions of the United States. As with the USCRN, RCRN stations have triple redundancy in temperature and precipitation measurements and are placed in pristine environments. Five-minute and hourly air temperature, plus precipitation data are collected. http://www.ncdc.noaa.gov/crn/img/maps/southwest-usrcrn.jpg