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Appendix C Major Systems Overview
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Major Systems Overview Information from Sensor Networks Parameters Surface Observations Public Sector Network • ASOS deployed in early to mid-1990s by NWS and FAA • Replaced human observer in most locations • Located at airports, WSFOs, etc. • 813 FAA and NWS ASOS • 180 DOD ASOS sensors • 1300 Federal AWOS • ~500 Non-federal AWOS • Another ~8500 COOP sensors Private Sector Networks • Deployed over last 20 years • School networks, local and state municipalities, utilities, television stations, private met companies • In most cases, provider maintains ownership rights to data • Approximately 10,000 sensors deployed • Also, ~2500 road-weather sensors deployed Other Federal Government Networks • Deployed in last 20 years • BLM, USDA, USGS, DOE, EPA, COE • ~13,000 sensors Technology • ASOS contains a hygrothermometer, mid-1990s by NWS and FAA cloud height indicator, and precipitation identifier • Some sites have icing detectors used for reporting freezing rain • Thunderstorm information is also available at most sites ASOS • Provides dewpoint, temperature, present weather, and visibility • Measures continuously and updates data every minute, but does not transmit them • Transmits an observation when SPECI criteria are met • All observed data are used in the algorithms to create the final observation. The algorithms are complex and vary from sensor to sensor AWOS • Transmits an observation every 20 minutes Maintenance • All of the ASOS sensors are on a 90-day preventive maintenance schedule • The ASOS Operations and Monitoring Center monitors the ASOS 24/7 and opens trouble tickets for flagged or missing data • ASOS sensor outages vary from 24 to 120 hours depending on the type of outage and the level of activity of the airport • Human observers augment the observations at all federal towered airports while tower is open • At larger airports, dedicated weather observers are on duty 24 hours a day to augment and backup the ASOS • NCDC can acquire data from nearby cooperative observing stations to replace missing data
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Processing Collection and Dissemination Overview • The information from automated sensors is collected, quality controlled, and formatted according to WMO standards if contributing to the climatological records • This does not preclude the use of sensors in private networks for private use; however, those sensors candidates for the government network • It is possible for the 1-minute data to be transmitted via FAA circuits. The FAA has recently begun transmitting These data are taken, along with other information, and processed by algorithms to provide local warnings to controllers at airports • The new processor for the ASOS would allow for the 1-minute data to be captured and disseminated to an Internet server. AWOS should also be able to be modified to do this Miscellaneous • COOP sensors are not automated— they still require humans to take readings (this technology is in the process of being upgraded) • Not all sensors have the same manufacturer, model number, last time calibrated, etc. Information is important as metadata to normalize information with other sensors and for long-term record keeping. Sensors without metadata are not useful for climatology, etc. • Not all sensors in “other-federal” category have weather sensors Collection • ASOS sensors connected via fiber optic cable to data collection package, which broadcasts data to processors in the airport control tower • At NWS sites, observations are sent via modem and dial lines to NWS computers at the local forecast offices for transmission over the AWIPS network to the NWSTG • At FAA sites, they are sent via dedicated circuits to an ARTCC then to the FAA communication centers in Atlanta and Salt Lake City before being routed to the NWSTG Dissemination • Via the Family of Services 9600 baud connection • Via the NOAA Port 3-T1 satellite broadcast • Via ftp from the OSO server in Silver Spring, Md. • Via the 4800 baud FAA-604 line
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Information from Sensor Networks Parameters Update Cycle • Disseminated from the NWS-FAA sensor every 20 minutes and updated when conditions warrant • Raw data are available at the ASOS for up to 12 hours. Processed METARs and SPEC1 are available for 31 days at ASOS, but only by NWS headquarters personnel Upper-Air Observations Public Sector • Weather balloons (radiosondes) launched twice a day at ~50 stations nationwide • Deployed since 1950s • Implemented at a subset of WSFOs throughout the country and other NMHS offices throughout the world • Approximately 1500 observations per day globally NOAA Profiler Network Public Sector • First system deployed in August 1989 • Last system deployed in May 1992 • 35 systems total—most in central U.S. • Approximately one-third of systems have temperature profiling capability in addition to wind profiling • NOAA basic agreement defines cooperative program between OAR and NWS Technology • Temperature and humidity sensor attached to a balloon using GPS for position reports and transmitter to downlink information via NOAA satellites • Wind speed and direction determined from movement of balloon Content • Wind speed and direction • Temperature • Humidity • Pressure Update Cycle • Launched globally every 12 hours Technology •“Clear air radar” technology using relatively long wavelengths (74 cm or 67 cm) • Temperature profiling is provided by a Radio Acoustic Sounding System • Each system has a surface meteorological sensor package • Each system also has a GPS-IPWV subsystem, which uses the GPS satellites to measure the amount of integrated precipitable water vapor in the atmosphere above the site Content • Profiles of horizontal wind speed and direction • Profiles of vertical wind speed and turbulence • During each cycle, measured raw data
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Processing Collection and Dissemination Overview • These sensors carried on balloons are still among the few in situ sensors that to provide vertical profiles of the atmosphere throughout the tropopause and lower stratosphere. Although the basic technology has not changed in recent years, using GPS for more accurate positioning of the balloon has shown great success in improving the wind speed and direction measurement • There are also plans to improve the accuracy of the relative humidity as well as provide more frequent updates of the information in the next few years Overview • Wind profilers are designed to measure vertical profiles of horizontal wind speed and direction from near the surface to above the tropopause • Algorithms convert radar returns to winds and perform quality control on the data prior to release. Birds are a significant quality control issue. Current configuration has central data collection hub; hub operating costs are not supported by NWS operational funds • Each profiler operates and provides data on 6- and 60-minute cycles. For each cycle approximately 3000 bytes of information are produced. An additional 128 bytes of information are added to each cycle with the application of quality control Collection • Data are transmitted from the balloon a NOAA communications satellite and back down to the NWS Camp Springs, Md., facility Dissemination • Via the Family of Services 9600 baud connection • Via the NOAA Port 3-T1 satellite broadcast • Via ftp from the OSO server in Silver Spring, Md. Collection • Primary collection is via dedicated 9.6 kbaud landline circuits directly from site to central processing facility in Boulder, Colo., every 6 minutes • Secondary collection is via a NOAA GOES-DCP 1-minute time slot (transmission rate at 100 baud) once per hour • In case of communications failure, the on-site receiver can store up to 10 days of data for later transmission Dissemination • Processed, quality-controlled data (profiler spectral moments, winds, temperatures; surface meteorological measurements; and GPS-IPWV are transmitted hourly via dedicated 56 kbaud landline circuit from Boulder, Colo., to the NWSTG
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Information from Sensor Networks Parameters are processed on-site into 3 spectral moments for 72 range gates (heights). On-site processing consists of 10 major steps including Fourier analysis, spectral averaging, power spectra calculations, D.C. and ground clutter removal, spectral moment calculations, and some quality control processing Update Cycle • Profiler wind and temperature acquisition cycle is 6 minutes. Typically 10 cycles are “averaged” together to form a single 1-hour average • Surface sensor cycle is 6 minutes • GPS data cycle is 30 minutes • No calibration of the profiler system is required • Surface meteorological sensors are calibrated by the NWS every year or after replacement • Replacement of defective parts is performed by NWS technicians MDCRS Commercial Aircraft Data Private Sector • Deployed since late 1980s • Voluntarily collected by airline partners • The current agreement is that the airlines own the data for real-time domestic use • Participating airlines (AAL, NWA, UAL, UPS, DAL, Federal Express) get corporate advantage from the raw reports • Data are openly available for all government use as well as research use • The data are freely exchanged with other international NWP centers via GTS • The redistribution restrictions do not apply for post-real-time use Technology • Temperature, wind, and pressure sensors are fitted on the aircraft and connected to the communications downlink for automatic reporting Content • Wind speed and direction • Wind speed and direction • Pressure Update Cycle • Dependent on airline—cost of communication is high • 80,000 to 100,000 reports per day from 500 aircraft • The airlines pay approximately 1 cent per observation. This can cost several hundred thousand dollars per year • ECMWF monitors the quality of these reports in real time, including development of error statistics for
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Processing Collection and Dissemination • For 35 profilers each having 240 6-minute and 24 60-minute cycles per day, this produces approximately 28.9 megabytes per day • A secondary backup method using the the Internet can be activated if the dedicated circuit fails • From the NWSTG, data are sent to the AWIPS WAN, NCEP, NOAA Port, and other NOAA organizations including NCDC, the Family of Services, and theGTS • NWS primary use of disseminated data is in the operational numerical weather prediction models and by local forecasters • At times, transmission to NWSTG and its corresponding notification of receipt are significantly delayed twice a day due to high traffic load at NWSTG. During these events, the delay results in data not being used in the weather models • 6- and 60-minute numerical profiler data, along with graphical displays, are also available in real time to the public from <http://profiler.noaa.gov> Overview • Basic in situ sensors have been on aircraft for a number of years • Newer technologies are being developed to generate derived products such as turbulence. Automated (rather than pilot-generated) turbulence reports will be added. • More tuning of the algorithm is needed. It is a software modification to existing systems of the aircraft, so no mechanical upgrades are required, but the increased data rate must be agreed upon Collection • Data are transmitted over a 1200-2400 baud VHF connection between aircraft and ground—then routed to NCEP • Sufficient bandwidth is available • The data are transmitted from individual aircraft to ARINC, where they are processed into BUFR format and sent to NWS and FAA at 5-minute intervals (the interval can be changed if needed). This is done via a T-1 type communications circuit • Alternative backup communications are being established between ARINC and NWS to ensure that all data are collected. The current delivery rate is well above 99% Dissemination • Not mass disseminated per airline request • Primarily used at NCEP for
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Information from Sensor Networks Parameters each aircraft. When “bad” reports are identified, ARINC is notified and it reports to the appropriate airline Doppler Radar Public Sector • Deployed NEXRAD (WSR-88d) in early to mid-1990s • Replaced 1957 and 1974 generation radars • Joint program between DOC, DOT, and DOD Private Sector • Deployed since early 1990 • Television stations, corporate sponsors, etc. • Located throughout CONUS • More than 150 radars Technology • NEXRAD Doppler radars connected to a 1988 generation processing system for converting to derived products • Narrow beamwidth, high-power translating to very sensitive returns • Range is 460 km for reflectivity products, 230 km for radial velocity and spectrum width products • Commercial systems have limited range of about half that of NEXARD Content • Base data consist of spectral width, velocity, and reflectivity at 0.25-km resolution • Derived products include base reflectivity (1, 2, and 4 km); composite reflectivity (4 km); radial velocity (0.25, 0.5, and 1 km); and hourly, 3-hourly, and storm total rainfall • Up to 177 mbytes of data are captured per hour Update Cycle • 14, 9, or 5 tilts available every 5, 6, or 10 minutes depending on mode • Subset of tilts available every 5, 6, or 10 minutes for dissemination • Commercial radars offer 1- to 2-minute updates Quality Control • Clutter suppression and range unfolding are performed at the RDA • Radar calibrated to within 1 dB using a national standard. Automatic calibration check performed each volume scan. Preventative maintenance inspections ensure continued calibration of radar
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Processing Collection and Dissemination operational models and forwarded to NOAA’s FSL for model development • All observations received at NCEP and FSL are stored—80,000-100,000 per day Overview • Three major benefits of the NEXRAD radars are the spectral width and velocity (Doppler) readings, increased sensitivity, and the postprocessing, which generates more useful derived products • Universities and government research labs developed algorithms for derived products as part of the NWS modernization program. Public domain software then populated privately manufactured radars that were sold concurrently with the government’s roll-out of the NEXRAD network. Today those radars are quite popular and quite powerful • There is a push among universities and some private sector entities to access the NEXRAD base data in addition to the derived products. These data can be used in NWP applications as well as input to private sector enhancements to derived product algorithms that have been slow to change within the government. The challenge is how to efficiently collect and disseminate this T-1 of information from 147 sites so that it is useful when it reaches its destination • A project spearheaded by the University of Oklahoma (CRAFT) has successfully prototyped the collection of base data from 58 sites in near real time Collection • Derived data are transmitted from the Radar Product Generator through the AWIPS processor at the radar site to the AWIPS-WAN • 154 of the 158 sites produce a set of 18 derived products, which are sent to the NWS Central Radar server. The NWS sites record a set of Level 3 products, which are archived at NCDC • The base data (Level 2) are recorded on 8-mm tapes and archived at NCDC. Base data from about 58 sites are sent to NCDC in near real time via the CRAFT project • Private sector data are being collected over a private network (in a requestreply mode) Dissemination • Subset of derived products in unaltered format disseminated over NOAA Port broadcast satellite • Complete set in unaltered format is available over a dedicated T-1 connection to the Central Radar server in Silver Spring, Md. • Subset of derived products in image format is available on NWS web site • Base data from up to 58 sites are available through CRAFT (until November 2002) • Private sector data have not been made available for mass dissemination
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Information from Sensor Networks Parameters • Local site technicians repair the radar as required. No data collected while the radar is inoperative Ocean Observations Public Sector • Marine Observation Network operated by NOAA’s National Data Buoy Center • 60 U.S. moored buoys • 49 C-MAN stations • 10 U.S. drifting buoys and floats • 900 voluntary observing ships • 250 buoys worldwide, regional and other national stations Academia • Regional coastal buoy networks used mainly for research Private Sector • More than 200 coastal sensors throughout the U.S. Technology • MON Buoys, C-MAN, and other station sensors calibrated by NDBC Calibration Laboratory. Pre- and postdeployment calibrations Content from MON Network • Air temperature • Sea-surface temperature • Sea-level pressure • Wind speed and direction • Continuous wind record • Humidity, dewpoint • Solar radiation • Surface ocean currents • Ocean current vertical profiles • Ocean temperature profiles • Significant wave heights • Average and dominant wave • Wave direction and power spectra • Swell direction and power spectra • Regional networks record onboard or report to a central facility Update Frequency • Hourly (public sector) • Four times per hour (private sector) Lightning Detection Private Sector • Owns and operates the National Lightning Detection Network • Deployed in late 1970s to early 1980s • Two networks merged to form Global Atmospherics, Inc., recently purchased by Vaisala, a Finnish company Technology • Triangulated location detection by ground-based sensors • NLDN consists of more than 100 remote, ground-based sensing stations located across the U.S. that instantaneously detect the electromagnetic signals given off when lightning strikes the Earth’s surface Content • Flash data and stroke data with date, time, latitude and longitude of flash or stroke, signal polarity, multiplicity, and amplitude
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Processing Collection and Dissemination Overview • All moored buoys and C-MAN stations report in real time via NOAA GOES DAPS. All drifting buoy and float data report via NOAA POES • VOS data reported via INMARSAT AMVER SEAS • All MON data are automatically quality controlled at the NWSTG and released to NOAA’s weather forecast offices, AWIPS, NCEP, U.S. National Archive Centers, internationally via GTS and the World Wide Web Collection • Moored buoy, C-MAN, drifting buoy, and float data are transmitted via NOAA GOES and POES to NOAA downlink at Wallops Island from the buoy to a NOAA communications satellite and back down to the NWS Camp Springs facility Dissemination • Via the Family of Services 19200 baud connection • Via GTS under WMO bulletins • Via the NOAA Port 3-T1 satellite broadcast to EMWIN • Via ftp from the NWS OSO server in Silver Spring, Md. • Via NOAA Weather Radio broadcast • Via AWIPS LAN • Via NDBC home page Overview • In the mid-1970s, three University of Arizona scientists, E. Philip Krider, Burt Pifer, and Martin Uman, began researching lightning properties and behavior. Over the next decade their research and the contributions of others resulted in the development of the only U.S. national lightning detection system, NLDN. Since 1989, the NLDN has monitored 20 million to 25 million cloud-to-ground lightning strikes that occur every year across the contiguous 48 states. The network operates 24 hours a day, 365 days a year Collection • Data are transmitted from over 100 remote sensors via a satellite-based communications network to the Network Control Center operated by Vaisala-GAI, Inc., in Tucson, Ariz. Within seconds of a lightning strike, the NCC’s central analyzers process information on the location, time, polarity, and amplitude of each strike. The lightning information is then communicated to users across the country Dissemination • Via 9600 baud satellite feed
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Information from Sensor Networks Parameters Update Cycle • Event driven (tenths of a second) Satellites Public Sector • NOAA’s National Environmental Satellite, Data and Information Service operates the nation’s GOES and POES • NESDIS operates two geostationary satellites, one monitoring North and South America and the Atlantic Ocean and the other monitoring North America and the Pacific Ocean • Complementing GOES are two POES, circling the Earth in sun-synchronous orbit at an altitude of 450 miles • In cooperation with DOD, NASA, and NOAA, NPOESS is planned to begin operations in 2008 Technology • Geostationary satellites remain at a fixed point over the Earth’s equator at an altitude of 23,000 miles above the Earth’s surface. They detect and track severe weather, including hurricanes, thunderstorms, flood-producing systems, and extratropical cyclones Content • Vertical profiles of temperature and humidity • Visible and infrared images of clouds and the Earth’s surface • Ocean temperatures (polar orbiting satellites) • Radiation measurements • Vegetation indices • In 2000 the NESDIS archive exceeded 1 petabyte (10 15 bytes) Update Cycle • GOES observe the atmosphere and Earth’s surface continuously. The POES pass over a given point on the Earth twice a day, so the two POES ensure that every point on Earth is measured four times a day NOTE: AAL = American Airlines; ARTCC = Air Route Traffic Control Center; ARINC = Aeronautical Radio, Inc.; ASOS = Automated Surface Observing System; AWIPS = Advanced Weather Prediction System; AWOS = Automated Weather Observing System; BLM = Bureau of Land Management; C-MAN = Coastal-Marine Automated Network; COOP = Cooperative Observer Program; DAL = Delta Airlines; COE = U.S. Army Corps of Engineers; CRAFT = Collaborative Radar Acquisition Field Test; DAPS = automated processing system; DOD = Department of Defense; DOE = Department of Energy; ECMWF = European Centre for Medium-Range Weather Forecasts; EMWIN = Emergency Managers Weather Information Network; EPA = Environmental Protection Agency; FAA = Federal Aviation Administration; FSL = Forecast Systems Laboratory; GAI = Global Atmospherics, Inc.; GPS = Global Positioning System; GPS-IPWV = Integrated Precipitable Water Vapor; GTS = Global Telecommunications System; INMARSAT AMVER SEAS = International Mobile Satellite Organization Automated Mutual-Assistance Vessel Rescue System Shipboard Environmental Data Acquisition System;
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Processing Collection and Dissemination Overview • GOES and POES are essential parts of the global observing system. They provide very high horizontal resolution data over the entire globe. These observations complement in situ observations, which tend to be concentrated over land areas. Satellite observations are especially important in the Southern Hemisphere, which has a very sparse network of in situ sensors • Satellite data are used by the public, private, and academic sectors for a variety of applications, including weather forecasting and warnings, climate monitoring, ocean services, and research • Other nations also operate geostationary and polar orbiting satellites, and these data are generally shared under the provisions of WMO Resolution 40 Collection • Data are downloaded from the satellites to ground-receiving stations and from there to NCEP and other users via landlines. Many users also have their own ground-based satellite data receivers and process the data directly upon receipt for their own uses ITWS = Integrated Terminal Weather System; MDCRS = Meteorological Data Collection and Reporting System; METAR = aviation routine weather report; MON = Marine Observation Network; NCC = Network Control Center; NCDC = National Climatic Data Center; NCEP = National Centers for Environmental Prediction; NDBC = National Data Buoy Center; NESDIS = National Environmental Satellite, Data and Information Service; NEXRAD = NEXt generation weather RADar; NPOESS = National Polar-Orbiting Operational Environmental Satellite System; NWA = Northwest Airlines; NLDN = National Lightning Detection Network; NMHS = National Meteorological and Hydrological Services; NWS = National Weather Service; NWP = Numerical Weather Prediction; NWSTG = NWS Telecommunications Gate; OAR = Office of Oceanic and Atmospheric Research; RDA = Radar Data Acquisition; SPECI = Special Meteorological Aeronautical Report; UAL = United Airlines; UPS = U.S. Postal Service; USDA = U.S. Department of Agriculture; USGS = U.S. Geological Survey; WMO = World Meteorological Organization; WSFO = NWS Forecast Office.
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