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Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)


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            title:  Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)
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                date:  2002-04-01
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                  Anchor:  DOI doi:10.7289/V5DR2SHD
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                code:  NCEI DSI 5909_01
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                code:  gov.noaa.ncdc:C00962
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                individualName:  Holub, Kirk
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                individualName:  Gutman, Seth
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        abstract:  The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based GPS receivers. The data contain observations from several hundred locations around the globe every 30 minutes from 2002-05-01 to 2016-11-28. However, most locations lie within the continental United States. The data set was formed in response to the need for improved moisture observations to support weather forecasting, climate monitoring, and research. The data set contains total precipitable water estimates, GPS total signal delay, GPS hydrostatic signal delay, GPS wet signal delay, surface temperature, surface pressure, mean-weighted surface temperature, and the wet delay mapping function. The GPS-IPW network processes data from both NOAA and other agency CORS (Continuously Operating Reference Sites) sites. All sites are equipped with a GPS receiver and many are equipped with a surface meteorological instrumentation package. GPS satellite observation are combined with GPS satellite orbit and earth orientation parameters to estimate GPS signal delay (Zenith Total Delay -- ZTD). Signal delays are then combined with surface meteorological information are used to estimate total precipitable water. For sites without surface meteorology sensors, data from nearby ASOS (Automated Surface Observing System) systems were used. Data set variables and their resolution: total precipitable water; 0.001 m, GPS total signal delay; 0.001m, GPS hydrostatic signal delay; 0.001m, GPS wet signal delay; 0.001m, surface temperature; 0.1 K, surface pressure; 0.1 hpa, mean-weighted surface temperature; 0.1 K, wet delay mapping function; 0.1 (dimensionless). Late updated in November 2016 with no plans for updating at this time due to funding.
        purpose:  The primary uses for the data set are to demonstrate the major aspects of an operational GPS integrated precipitable water vapor (IPW) monitoring system, facilitate assessments of the impact of these data on weather forecasts, assist in the transition of these techniques to operational use, and encourage the use of GPS meteorology for atmospheric research and other applications.
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            otherConstraints:  Cite as: Holub, Kirk L. and Gutman, Seth I. (2016):Ground-Based Global Positioning System (GPS) Meteorology, Version 1.0. NOAA National Centers for Environmental Information (NCEI). doi:10.7289/V5DR2SHD [access date].
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                title:  Rapid Retrieval and Assimilation of Ground Based GPS Precipitable Water Observations at the NOAA Forecast Systems Laboratory: Impact on Weather Forecasts
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                    code: http://doi.org/10.2151/jmsj.2004.351
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                            name:  Rapid Retrieval and Assimilation of Ground Based GPS Precipitable Water Observations at the NOAA Forecast Systems Laboratory: Impact on Weather Forecasts
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            associationType:  (DS_AssociationTypeCode) source
            initiativeType:  (DS_InitiativeTypeCode) sciencePaper
        spatialRepresentationType:  (MD_SpatialRepresentationTypeCode) textTable
        spatialResolution:  (MD_Resolution)
            distance:
              Distance:  10000
        language:  eng; USA
        topicCategory:  (MD_TopicCategoryCode) climatologyMeteorologyAtmosphere
        environmentDescription:  The network is controlled by a software system developed by ESRL/GSD in conjunction with the Scripps Institution of Oceanography (SIO) and the University of Hawaii at Manoa (UH). GPS precise predicted orbits from Scripps Orbit and Permanent Array Center (SOPAC) and data from individual sites (GPS and MET) are continuously downloaded by a server. At the beginning of a processing cycle, several processing nodes download the GPS data and predicted orbits for selected sites from the server. The GAMIT (GPS at MIT [http://www-gpsg.mit.edu/~simon/gtgk]) software package provided by the Massachusetts Institute of Technology (MIT) processes this data and produces Tropospheric Signal Delay (ZTD) values (illustrated below.) These values are then processed with Meteorology data from the sites to produce and Integrated Precipitable Water Values (IPW) which are then distributed to interested parties and made available online. The processing system incorporates an 8 hour sliding window technique, with two processing cycles for each hour starting at 02 and 32 minutes after the hour. Each cycle produces 16 individual IPW for each half hour within the sliding window. As the 8 hour sliding window progresses throughout the day, more IPW are produced for each half hour until that particular half hour is no longer within the sliding window. This produces a possibility of 16 values for each half hour. Within each half hour, two IPW are available, a first guess and median value. The first guess IPW is the first value for the half hour meeting the quality control criteria. The median IPW is the median of all results for that particular half hour. This result can be the median of 1 to 16 values depending upon quality control criteria.
        extent:  (EX_Extent)
            geographicElement:  (EX_GeographicBoundingBox)
                extentTypeCode:  1
                westBoundLongitude:  -180.0
                eastBoundLongitude:  180.0
                southBoundLatitude:  -90.0
                northBoundLatitude:  90.0
            temporalElement:  (EX_TemporalExtent)
                extent:
                  TimePeriod:
                    description:  ground condition
                    beginPosition:  2002-04-01
                    endPosition:  2016-11-29
                    timeInterval:  30
        supplementalInformation:  The near real-time estimates of IPW have a resolution is 30 minutes. They are based on GPS signal delay estimates and surface pressure and temperature observations.
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    distributionInfo:  (MD_Distribution)
        distributor:  (MD_Distributor)
            distributorContact:  (CI_ResponsibleParty)
                organisationName:  NOAA National Centers for Environmental Information
                contactInfo:  (CI_Contact)
                    address:  (CI_Address)
                        electronicMailAddress:  ncei.info@noaa.gov
                    onlineResource:  (CI_OnlineResource)
                        linkage: https://www.ncei.noaa.gov/contact
                        name:  NCEI Contact Information
                        description:  Information for contacts at NCEI.
                        function:  (CI_OnLineFunctionCode) information
                role:  (CI_RoleCode) distributor
            distributionOrderProcess:  (MD_StandardOrderProcess)
                fees:  In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
                orderingInstructions:  Contact NCEI for other distribution options and instructions.
            distributorFormat:  (MD_Format)
                name:  XML
                version: (missing)
            distributorFormat:  (MD_Format)
                name:  netCDF-3
                version: (missing)
            distributorTransferOptions:  (MD_DigitalTransferOptions)
                onLine:  (CI_OnlineResource)
                    linkage: https://doi.org/10.7289/V5DR2SHD
                    protocol:  HTTPS
                    applicationProfile:  Landing Page
                    name:  NCEI Dataset Landing Page
                    description:  Landing page for the dataset.
                    function:  (CI_OnLineFunctionCode) information
            distributorTransferOptions:  (MD_DigitalTransferOptions)
                transferSize: (missing)
                onLine:  (CI_OnlineResource)
                    linkage: https://www.ncei.noaa.gov/data/gpsmet/
                    protocol:  HTTPS
                    applicationProfile:  Download
                    name:  NOAA NCEI website for ESRL Ground-Based GPS Meteorology data
                    description:  NCEI website for downloading ESRL Ground-Based GPS Meteorology data
                    function:  (CI_OnLineFunctionCode) download
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    dataQualityInfo:  (DQ_DataQuality)
        scope:  (DQ_Scope)
            level:  (MD_ScopeCode) dataset
            extent:  #boundingExtent
        lineage:  (LI_Lineage)
            statement:  The purpose of the National Oceanic and Atmospheric Administration's (NOAA) Ground-Based GPS-IPW project (gpsmet) was to: Evaluate the engineering and scientific bases of surface-based GPS meteorology; demonstrate the feasibility and utility of using surface-based GPS observations for improved weather forecasting, climate monitoring, and satellite sensor calibration/validation; transfer this observing system technology to operational use. The Global Systems Division (GSD) Demonstration Branch (DB) (now Global Systems Division [GSD]) established the world's first GPS network dedicated to atmospheric remote sensing in 1994. This project was a collaboration between NOAA Research and several organizations and institutions including: NOAA's National Geodetic Survey (NGS) which manages the network of Continuously Operating Reference Stations (CORS); including some of the GSD/DB GPS-IPW network sites, NOAA's National Data Buoy Center (NDBC), The U.S. Department of Transportation Federal Highway Administration (DOT), The U.S. Coast Guard (USCG) International GPS Service (IGS) which maintains global network of tracking sites; including some of the GSD/DB GPS-IPW network sites, Scripps Institution of Oceanography (SIO) University of Hawaii at Manoa (UHhttp://lumahai.soest.hawaii.edu/Dept/meteorology/index.html), UNAVCO (UNAVCO) The Department of Energy Atmospheric Radiation Measurement (ARM) Program. All processing software and products used or created by the gpsmet processing system reside on GSD systems or at NCEI archives.
            processStep:  (LE_ProcessStep)
                description:  Estimation of IPW required two components; an estimate of ZTD and observations of the surface pressure and temperature. Estimation of ZTD began the acquiring GPS observation data from a collection of GPS CORS sites. These observations were used as inputs, along with earth orientation parameters (OEP) and internal terrestrial reference frame (ITRF) parameters, by GAMIT to estimate ZTD. Once ZTD had been estimated it separated into two components, wet and dry, using surface meteorological data. In the final step IPW was estimated by applying an empirical mapping parameter to the the estimated wet component.
                rationale:  Estimation of IPW required two components; an estimate of ZTD and observations of the surface pressure and temperature. ZTD cannot be directly observed by the GPS receivers. It must be obtained by processing the GPS observations.
                dateTime: (missing)
                processor:  (CI_ResponsibleParty)
                    organisationName:  DOC/NOAA/OAR/ESRL/GSD/ > Global Systems Division, Earth System Research Laboratory, OAR, NOAA, U.S. Department of Commerce
                    role:  (CI_RoleCode) processor
                source:  sd001
                source:  sd002
                processingInformation:  (LE_Processing)
                    identifier:  (MD_Identifier)
                        code:  gpsmet processing system
                    algorithm:  (LE_Algorithm)
                        citation:  (CI_Citation)
                            title:  A NEW COMPOSITE OBSERVING SYSTEM STRATEGY FOR GROUND-BASED GPS METEOROLOGY
                            date:  (CI_Date)
                                date:  2003-02-11
                                dateType:  (CI_DateTypeCode) publication
                            citedResponsibleParty:  (CI_ResponsibleParty)
                                organisationName:  DOC/NOAA/OAR/ESRL/GSD/ > Global Systems Division, Earth System Research Laboratory, OAR, NOAA, U.S. Department of Commerce
                                role:  (CI_RoleCode) author
                            citedResponsibleParty:  (CI_ResponsibleParty)
                                organisationName: (missing)
                                contactInfo:  (CI_Contact)
                                    onlineResource:  (CI_OnlineResource)
                                        linkage: https://ams.confex.com/ams/pdfpapers/54168.pdf
                                        protocol:  HTTPS
                                        applicationProfile:  Web Browser
                                        name:  A NEW COMPOSITE OBSERVING SYSTEM STRATEGY FOR GROUND-BASED GPS METEOROLOGY
                                        description:  Presented at AMS 12th Symposium on Meteorological Observations and Instrumentation
                                        function:  (CI_OnLineFunctionCode) information
                                role: (missing)
                        description:  See Algorithm Citation
            source:  (LE_Source)
                description:  GPS carrier phase observations
                sourceCitation:  (CI_Citation)
                    title:  GPS carrier phase observation
                    date:  (CI_Date)
                        date:  1994-01-01
                        dateType:  (CI_DateTypeCode) publication
                    citedResponsibleParty:  (CI_ResponsibleParty)
                        organisationName:  DOC/NOAA/NOS > National Ocean Service, NOAA, U.S. Department of Commerce
                        role:  (CI_RoleCode) distributor
                    citedResponsibleParty:  (CI_ResponsibleParty)
                        organisationName: (missing)
                        contactInfo:  (CI_Contact)
                            onlineResource:  (CI_OnlineResource)
                                linkage: http://www.ngs.noaa.gov/CORS
                                applicationProfile:  Web Browser
                                name:  GPS carrier phase observation
                                description:  GPS observation data
                                function:  (CI_OnLineFunctionCode) information
                        role: (missing)
                sourceExtent:  (EX_Extent)
                    geographicElement:  (EX_GeographicBoundingBox)
                        extentTypeCode:  1
                        westBoundLongitude:  180
                        eastBoundLongitude:  180
                        southBoundLatitude:  90
                        northBoundLatitude:  90
                    temporalElement:  (EX_TemporalExtent)
                        extent:
                          TimePeriod:
                            beginPosition:  2002-04-01
                            endPosition:  2016-11-29
                sourceStep:  ps001
            source:  (LE_Source)
                description:  Meteorological observations
                sourceCitation:  (CI_Citation)
                    title:  surface meteorological observations
                    date: (missing)
                    citedResponsibleParty:  (CI_ResponsibleParty)
                        organisationName:  DOT/FAA
                        role:  (CI_RoleCode) distributor
                    citedResponsibleParty:  (CI_ResponsibleParty)
                        organisationName: (missing)
                        contactInfo:  (CI_Contact)
                            onlineResource:  (CI_OnlineResource)
                                linkage: http://aviationweather.gov/adds/dataserver_current/current/
                                applicationProfile:  Web Browser
                                name:  surface meteorological observations
                                description:  surface meteorological observation from ASOS sites
                                function:  (CI_OnLineFunctionCode) information
                        role: (missing)
                sourceExtent:  (EX_Extent)
                    geographicElement:  (EX_GeographicBoundingBox)
                        extentTypeCode:  1
                        westBoundLongitude:  180
                        eastBoundLongitude:  180
                        southBoundLatitude:  90
                        northBoundLatitude:  90
                    temporalElement:  (EX_TemporalExtent)
                        extent:
                          TimePeriod:
                            beginPosition:  gco:nilReason="missing"/
                            endPosition:  2016-11-29
                sourceStep:  ps001
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    dataQualityInfo:  (DQ_DataQuality)
        scope:  (DQ_Scope)
            level:  (MD_ScopeCode) repository
            levelDescription:  (MD_ScopeDescription)
                other:  NOAA National Centers for Environmental Information
        lineage:  (LI_Lineage)
            processStep:  (LE_ProcessStep)
                description:  NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
                dateTime:
                  DateTime:  2015-04-22T00:00:00
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    metadataMaintenance:  (MD_MaintenanceInformation)
        maintenanceAndUpdateFrequency:  (MD_MaintenanceFrequencyCode) asNeeded
        maintenanceNote:  Bulk metadata change applied on 2023-06-23. See version control repository history for metadata change details.