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Global Navigation Satellite System (GNSS) IGS Real-Time Clock Combination of Real-Time Analysis Center (AC) Submissions Product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System satellite and receiver clock combination product (30-second granularity, daily files, generated daily) from the real-time IGS analysis center submissions available from NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. The CDDIS provides access to products generated from real-time data streams in support of the IGS Real-Time Service. The real-time observation data from a global permanent network of ground-based receivers are transmitted from the CDDIS in 1 to multi-second intervals in raw receiver or RTCM (Radio Technical Commission for Maritime Services) format. These real-time data are utilized to generate near real-time product streams. The real-time products consist of GNSS satellite orbit and clock corrections to the broadcast ephemeris. These correction streams are formatted according to the RTCM SSR standard for State Space Representation and are broadcast using the NTRIP protocol. IGS analysis centers (ACs) access GNSS real-time data streams to produce GNSS satellite and ground receiver clock values in real-time. The product streams are combination solutions generated by processing individual real-time solutions from participating IGS Real-time ACs. The IGS Real-Time Analysis Center Coordinator (RTACC) uses these individual AC solutions to generate this real-time IGS combined satellite and receiver clock product. The effect of combining the different AC solutions is a more reliable and stable performance than that of any single AC's product. This clock solution is a batch combination based on daily clock submissions by these IGS real-time analysis centers and have been provided since February 2009, shortly after real-time streams were routinely available through the IGS Real-Time Pilot Project and prior to the availability of real-time product streams. Clock solution files consist of decoded clock results from the real time stream at 30-second intervals. This combination is a daily solution available approximately one to three days after the end of the previous UTC day. All satellite and receiver clock solution files utilize the clock RINEX format and span 24 hours from 00:00 to 23:45 UTC.

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Global Navigation Satellite System (GNSS) IGS Analysis Center (AC) Final Station Positions/Velocities Product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Final Combined Station Positions/Velocities Product available from the Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce precise orbits identifying the position and velocity of the GNSS satellites as well as precise station positions and velocities for the network of GNSS receivers. The IGS Reference Frame Coordinator uses these individual AC solutions to generate the official IGS station position/velocity product. The final AC products consist of daily and weekly station position and velocity files in SINEX format, generated on a daily/weekly basis and are available approximately 11-17 days after the end of the solution week.

Global Navigation Satellite System (GNSS) IGS Final Analysis Center (AC) Earth Rotation Parameters (ERP) Product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Final Earth Rotation Parameter (ERP) Product from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to generate GNSS-based ERP products. The IGS Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS final ERP product. The final products are considered the most consistent and highest quality IGS solutions; they consist of daily orbit, clock, and ERP files, generated on a weekly basis with a delay up to 13 (for the last day of the week) to 20 (for the first day of the week) days. All ERP solution files utilize the IGS ERP file format and span 24 hours from 00:00 to 23:45 UTC.

LMOS UC-12 In-Situ Meteorological and Navigational Data

LMOS_MetNav_AircraftInSitu_UC12_Data_1 is the Lake Michigan Ozone Study (LMOS) in-situ meteorological and navigational data collected onboard the NASA UC-12 aircraft during the LMOS field campaign. This product is a result of a joint effort across multiple agencies, including NASA, NOAA, the EPA, Electric Power Research Institute (EPRI), National Science Foundation (NSF), Lake Michigan Air Directors Consortium (LADCO) and its member states, and several research groups at universities. Data collection is complete.Elevated spring and summertime ozone levels remain a challenge along the coast of Lake Michigan, with a number of monitors recording levels/amounts exceeding the 2015 National Ambient Air Quality Standards (NAAQS) for ozone. The production of ozone over Lake Michigan, combined with onshore daytime “lake breeze” airflow is believed to increase ozone concentrations at locations within a few kilometers off shore. This observed lake-shore gradient motivated the Lake Michigan Ozone Study (LMOS). Conducted from May through June 2017, the goal of LMOS was to better understand ozone formation and transport around Lake Michigan; in particular, why ozone concentrations are generally highest along the lakeshore and drop off sharply inland and why ozone concentrations peak in rural areas far from major emission sources. LMOS was a collaborative, multi-agency field study that provided extensive observational air quality and meteorology datasets through a combination of airborne, ship, mobile laboratories, and fixed ground-based observational platforms. Chemical transport models (CTMs) and meteorological forecast tools assisted in planning for day-to-day measurement strategies. The long term goals of the LMOS field study were to improve modeled ozone forecasts for this region, better understand ozone formation and transport around Lake Michigan, provide a better understanding of the lakeshore gradient in ozone concentrations (which could influence how the Environmental Protection Agency (EPA) addresses future regional ozone issues), and provide improved knowledge of how emissions influence ozone formation in the region.

Ground-Based Global Navigation Satellite System (GNSS)-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN) GPS daily antenna phase maps (meta data, 24-hour files) from NASA CDDIS

This product contains file names and URLs to files containing antenna phase map data used in the real-time GPS POD processing. In particular, the IGS ANTEX file name used for the processing is provided. Additional meta data items may include information that identifies the real-time filter source populating the GPS real-time POD products (see "pos", "quat", and "tdp" products). The product is generated at JPL's Global Differential GPS Operations Centers.

Global Navigation Satellite System (GNSS) IGS Combined Rapid Clock Solution Comparison Summary Product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Rapid Clock Product Summary from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce GNSS satellite and ground receiver clock values. The IGS Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS rapid combined satellite and receiver clock products. The rapid combination is a daily solution available approximately 17 hours after the end of the previous UTC day. All satellite and receiver clock solution files utilize the clock RINEX format and span 24 hours from 00:00 to 23:45 UTC. The solution summary file details information about the generation of the daily rapid combined clock products and comparison with the individual AC solutions. The reduced latency on availability of these products allows for significantly improved orbit predictions and reduced errors for user applications.

Ground-Based Global Navigation Satellite System (GNSS) Satellite-Based Augmentation System (SBAS) Broadcast Ephemeris Data (30-second sampling, hourly files) from NASA CDDIS

This dataset consists of ground-based Global Navigation Satellite System (GNSS) Satellite-Based Augmentation System (SBAS) Broadcast Ephemeris Data (hourly files) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLONASS. Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. The hourly SBAS broadcast ephemeris files contain one day of SBAS broadcast navigation data in RINEX format from a global permanent network of ground-based receivers, one file per site. More information about these data is available on the CDDIS website at https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/hourly_30second_data.html.

Global Navigation Satellite System (GNSS) IGS Final Analysis Center (AC) Troposphere Zenith Path Delay (ZPD) product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Final Troposphere Zenith Path Delay (ZPD) Product (daily files by station) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce troposphere ZPD estimates for stations of the IGS network. The primary troposphere products generated from ground-based GNSS data are estimates of total zenith path delay and north/east troposphere gradient. Ancillary measurements of surface pressure and temperature allow the extraction of precipitable water vapor from the total zenith path delay. The IGS Troposphere Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS troposphere ZPD estimates for many of the stations in the IGS network. The final AC products consist of daily files containing data from each observing station. All ZPD solution files utilize the Solution INdependent EXchange format for combination of TROpospheric estimates (SINEX_TRO) and span 24 hours from 00:00 to 23:45 UTC.

Global Navigation Satellite System (GNSS) IGS Rapid Orbit/Clock/Earth Rotation Parameters (ERP) Product Summary from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Rapid Orbit/Reference Frame Product Summary from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce GNSS satellite and ground receiver clock values. The IGS Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS rapid combined orbit, satellite and receiver clock, and ERP products. The rapid combination is a daily solution available approximately 17 hours after the end of the previous UTC day. All satellite and receiver clock solution files utilize the clock RINEX format and span 24 hours from 00:00 to 23:45 UTC. The solution summary file details information about the generation of the daily rapid products.

GPM GROUND VALIDATION NASA ER-2 NAVIGATION DATA MC3E

The GPM Ground Validation NASA ER-2 Navigation Data MC3E dataset contains information recorded by an on board navigation recorder (NavRec). In addition to typical navigation data (e.g. date, time, lat/lon and altitude) it contains outside meteorological parameters such as wind speed, wind direction, and temperature. These ASCII text files were recorded every second for the length of the flight. The Flight Summaries and Flight Track Imagery dataset which includes sonde maps, radar animation, and 5-minute KICT track snapshots is distributed with this dataset.

Ground-Based Global Navigation Satellite System (GNSS) GLObal NAvigation Satellite System (GLONASS) Hatanaka-Compressed Observation Data (30-second sampling, daily files) from NASA CDDIS

GNSS receivers collect the signals from orbiting satellites to determine their location in three dimensions and calculate precise time. GNSS receivers detect, decode, and process both pseudorange (code) and phase transmitted by the GNSS satellites. The satellites transmit the ranging codes on two or more radio-frequency carriers, allowing the locations of GNSS receivers to be determined with varying degrees of accuracy, depending on the receiver and post-processing of the data. The receivers also calculate current local time to high precision facilitating time synchronization applications.This dataset consists of ground-based Global Navigation Satellite System (GNSS) GLONASS Compact Observation Data (30 second sampling, daily, 24 hour files) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. The GLONASS data sets from ground receivers at the CDDIS consist of observations from the Russian GLObal NAvigation Satellite System (GLONASS); Russia's GLONASS is similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. The daily GLONASS compact observation data files contain one day of GLONASS observation (30-second sampling) data in RINEX format from a global permanent network of ground-based receivers, one file per site.

Ground-Based Global Navigation Satellite System (GNSS) Indian Regional Navigation Satellite System (IRNSS) Broadcast Ephemeris Data (30-second sampling, hourly files) from NASA CDDIS

This dataset consists of ground-based Global Navigation Satellite System (GNSS) Indian Regional Navigation Satellite System (IRNSS) Broadcast Ephemeris Data (hourly files) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLONASS. Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. The hourly IRNSS broadcast ephemeris files contain one hour of IRNSS broadcast navigation data in RINEX format from a global permanent network of ground-based receivers, one file per site.

ARCSIX Learjet In-Situ Meteorology and Navigation Data

ARCSIX_MetNav_AircraftInSitu_Learjet_Data is the in-situ meteorology and navigation data collected onboard the Learjet aircraft during the Arctic Radiation-Cloud-Aerosol-Surface Interaction EXperiment (ARCSIX) campaign. Data collection for this product is complete.The ARCSIX campaign is a NASA field investigation aimed at quantifying the contributions of surface properties, clouds, aerosol particles, and precipitation to the Arctic summer surface radiation budget and sea ice melt during the early melt season. Based out of Greenland, ARCSIX completed two deployments from May – June 2024 and July - August 2024 utilizing the NASA P-3B, LaRC G-III, and SPEC-Learjet aircraft. The P-3B was equipped with in situ and remote sensing payloads to acquire measurements of aerosols, cloud, and radiation properties. The high-flying LaRC G-III was equipped with remote sensing instrumentation, including the HALO, and HSRL, along with the AVAPS dropsonde system. The SPEC-Learjet acquired measurements of cloud microphysics. Data were also collected at the Thule High Arctic Atmospheric Observatory (THAAO) in Pituffik, Greenland. The primary objective of ARCSIX was to enhance long-term space-based monitoring and predictive capabilities of Arctic sea ice, cloud, and aerosols by validating and improving remote sensing algorithms and model parameterizations in the Arctic. ARCSIX science questions focused on examining the impact of the predominant summer Arctic cloud types on the radiative surface energy budget, what processes control the evolution and maintenance of the predominant cloud types in the summertime Arctic, and how do the two-way interactions between surface properties and atmospheric forcings affect sea ice evolution?

Global Navigation Satellite System (GNSS) IGS Final Combined Satellite and Receiver Clock Solution (5 minute resolution, daily files, generated weekly) product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System Final Satellite and Receiver Clock Product (5-minute granularity, daily files, generated weekly) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce GNSS satellite and ground receiver clock values. The IGS Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS final combined satellite and receiver clock products. The final products are considered the most consistent and highest quality IGS solutions; they consist of daily orbit files, generated on a weekly basis with a delay up to 13 (for the last day of the week) to 20 (for the first day of the week) days. All satellite and receiver clock solution files utilize the clock RINEX format and span 24 hours from 00:00 to 23:45 UTC.

Ground-Based Global Navigation Satellite System (GNSS)-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN) Galileo Earth Orientation Parameters (1-day sampling, 7-day files) from NASA CDDIS

This product contains a time series of Earth orientation parameters from the IERS Bulletin A for the Galileo constellation of satellites. The product is generated at JPL's Global Differential GPS Operations Centers.

CAMEX-3 DC-8 NAVIGATION (DADS) DATA

The CAMEX-3 DC-8 Navigation Data Acquisition and Distribution System (DADS) data files contain information recorded by navigation and data collection systems onboard the NASA DC-8 aircraft. These data files contain typical navigation data (e.g. date, time, lat/lon, altitude), and meteorological parameters (e.g. wind speed and direction, temperature, saturation vapor pressure) collected in support of the third field campaign in the Convection And Moisture EXperiment (CAMEX) series, CAMEX-3. This field campaign took place from August to September 1998 based out of Patrick Air Force Base in Florida, with the purpose of studying various aspects of tropical cyclones in the region. These data are available in ASCII file format with browse imagery available in GIF file format. Each file contains data recorded at one second intervals for each flight.

Ground-Based Global Navigation Satellite System (GNSS)-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN) GLONASS daily antenna phase centers (24-hour files) from NASA CDDIS

This product contains antenna phase center locations relative to the GLONASS satellite's center of mass. The product is generated at JPL's Global Differential GPS Operations Centers.

DEVOTE B-200 Aircraft In-Situ Meteorological and Navigational Data

DEVOTE_MetNav_AircraftInSitu_B200_Data are in-situ meteorological and navigational data collected onboard the B-200 aircraft as part of the Development and Evaluation of satellite Validation Tools by Experimenters (DEVOTE) sub-orbital project. Data from the NAV420 CrossBow Inertial Measurement Unit (IMU) Navigational Data and 2 Diode Laser Hygrometer (DLH) instruments are included in this product. Data collection is complete.The Development and Evaluation of satellite Validation Tools by Experimenters (DEVOTE) project investigated aerosols and clouds with the specific goals of satellite validation and the improvement of satellite data retrieval algorithms. Conducted in September and October 2011, DEVOTE scientists collected measurements of aerosols and cloud optical and microphysical properties using airborne sensors over ground sites and along satellite overpasses to demonstrate the use of airborne platforms in future scientific measurement campaigns. These measurements were used to validate and improve satellite data retrieval algorithms from missions including the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission and the Aerosol, Cloud, Ecosystems (ACE) Decadal Survey mission.DEVOTE scientists conducted eleven science flights based at the NASA Langley Research Center throughout the campaign. The flight plans were specifically designed to coordinate with CALIPSO satellite overpasses and to fly over the Aerosol Robotic Network (AERONET) ground network sites. The DEVOTE sampling strategy required two aircraft dedicated to remote sensing and in-situ observations, which flew in coordinated flight patterns. This was implemented through use of the NASA UC-12 and the NASA B-200 airborne platforms. The UC-12 had the following remote sensing payload: the Research Scanning Polarimeter (RSP) and High Spectral Resolution Lidar (HSRL) instruments. The B-200 had an in-situ payload including the Polarized Imaging Nephelometer (PI-Neph), the DLH, and Langley Aerosol Research Group Experiment (LARGE) instruments for aerosol microphysical and optical properties.DEVOTE was partly funded through the Hands-On Project Experience (HOPE) initiative. HOPE was a NASA development program designed to offer early career scientist opportunities to design, implement, and analyze small missions offering hands-on experience. Opportunities are increasingly limited for principal investigators, program managers, and system engineers to obtain mission life cycle training, and HOPE provides opportunities to those early on in their career or who are transitioning to a different field. Thus, DEVOTE had a focus on providing hands-on training in the mission life cycle to early career scientists in addition to its primary objective of using cloud and aerosol data collected from airborne sensors to validate and improve satellite data retrieval algorithms. Additionally, the information obtained from DEVOTE research was used to prepare for the implementation of ACE.

LISTOS NASA Aircraft Meteorological and Navigational Data

LISTOS_MetNav_AircraftInSitu_NASAAircraft_Data is the Long Island Sound Tropospheric Ozone Study (LISTOS) in-situ meteorological and navigational data collected onboard the NASA aircraft during the LISTOS field campaign. This product is a result of a joint effort across multiple agencies, including NASA, NOAA, the EPA Northeast States for Coordinated Air Use Management (NESCAUM), Maine Department of Environmental Protection, New Jersey Department of Environmental Protection, New York State Department of Environmental Conservation and several research groups at universities. Data collection is complete.The New York City (NYC) metropolitan area (comprised of portions of New Jersey, New York, and Connecticut in and around NYC) is home to over 20 million people, but also millions of people living downwind in neighboring states. This area continues to persistently have challenges meeting past and recently revised federal health-based air quality standards for ground-level ozone, which impacts the health and well-being of residents living in the area. A unique feature of this chronic ozone problem is the pollution transported in a northeast direction out of NYC over Long Island Sound. The relatively cool waters of Long Island Sound confine the pollutants in a shallow and stable marine boundary layer. Afternoon heating over coastal land creates a sea breeze that carries the air pollution inland from the confined marine layer, resulting in high ozone concentrations in Connecticut and, at times, farther east into Rhode Island and Massachusetts. To investigate the evolving nature of ozone formation and transport in the NYC region and downwind, Northeast States for Coordinated Air Use Management (NESCAUM) launched the Long Island Sound Tropospheric Ozone Study (LISTOS). LISTOS was a multi-agency collaborative study focusing on Long Island Sound and the surrounding coastlines that continually suffer from poor air quality exacerbated by land/water circulation. The primary measurement observations took place between June-September 2018 and include in-situ and remote sensing instrumentation that were integrated aboard three aircraft, a network of ground sites, mobile vehicles, boat measurements, and ozonesondes. The goal of LISTOS was to improve the understanding of ozone chemistry and sea breeze transported pollution over Long Island Sound and its coastlines. LISTOS also provided NASA the opportunity to test air quality remote sensing retrievals with the use of its airborne simulators (GEOstationary Coastal and Air Pollution Events (GEO-CAPE) Airborne Simulator (GCAS), and Geostationary Trace gas and Aerosol Sensory Optimization (GeoTASO)) for the preparation of the Tropospheric Emissions; Monitoring of Pollution (TEMPO) observations for monitoring air quality from space. LISTOS also helped collaborators in the validation of Tropospheric Monitoring Instrument (TROPOMI) science products, with use of airborne- and ground-based measurements of ozone, NO2, and HCHO.

Global Navigation Satellite System (GNSS) IGS Rapid High-Rate Ionosphere Vertical Total Electron Content (VTEC) Grid Product from NASA CDDIS

This derived product set consists of Global Navigation Satellite System a high-rate Ionosphere Vertical Total Electron Content (VTEC) product (daily files) from the NASA Crustal Dynamics Data Information System (CDDIS). The VTEC product files also include Delay Code Bias (DCB) values for GNSS satellites and ground receivers derived during the analysis. GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. GNSS observations from a global network can be utilized for atmospheric measurements. Analysis Centers (ACs) of the International GNSS Service (IGS) retrieve GNSS data on regular schedules to produce independently computed VTEC maps. The IGS Ionosphere Analysis Center Coordinator (ACC) uses these individual AC solutions to generate the official IGS VTEC maps. The high-rate VTEC maps are computed with a resolution of every hour or every quarter hour in UT, 5 degrees in longitude and 2.5 degrees in latitude; they are available with a one day latency.