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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.

MLS/Aura Near-Real-Time L2 Temperature V005 (ML2T_NRT) at GES DISC

ML2T_NRT is the EOS Aura Microwave Limb Sounder (MLS) Near-Real-Time (NRT) product for temperature. This product contains temperature profiles derived from the 118 GHz region. The NRT data are typically available within 3 hours of observation and are broken into files containing about 15 minutes of data. The most recent 7 days of data are available online. Spatial coverage is near-global (-82 degrees to +82 degrees latitude), with each profile spaced 1.5 degrees or ~165 km along the orbit track (roughly 15 orbits per day). The vertical coverage is from 215 to 0.001 hPa. The MLS NRT algorithm uses a simplified fast forward model to meet Near Real Time data latency requirements and are therefore not as accurate as the retrievals that constitute the standard MLS products. Nevertheless the results are scientifically useful in selected regions of the Earth's atmosphere provided that the data are screened according to the recommendations in the MLS NRT User Guide and the MLS L2 Data Quality Document for Standard Products.

MODIS/Terra Near Real Time (NRT) L2 Surface Reflectance, 5-Min Swath 250m, 500m, and 1km

MODIS/Terra Near Real Time (NRT) L2 Surface Reflectance, 5-Min Swath 250m, 500m, and 1km (MOD09). This product is computed from the MODIS Level 1B land bands 1, 2, 3, 4, 5, 6, and 7 (centered at 648 nm, 858 nm, 470 nm, 555 nm, 1240 nm, 1640 nm, and 2130 nm, respectively). The product is an estimate of the surface spectral reflectance for each band as it would have been measured at ground level if there were no atmospheric scattering or absorption. The surface-reflectance product is the input for product generation for several land products: vegetation Indices (VIs), BRDF, thermal anomaly, snow/ice, and Fraction of Photosynthetically Active Radiation/Leaf Area Index (FPAR/LAI).

MODIS/Aqua Near Real Time (NRT) Temperature and Water Vapor Profiles 5-Min L2 Swath 5km

The level-2 MODIS Temperature and Water Vapor Profile Product MYD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature and moisture profiles, total atmospheric water vapor, and total ozone. All of these parameters are produced for both daytime and nighttime conditions at 5-km pixel resolution when at least 9 FOVs are cloud free. The atmospheric profiles are produced at 20 vertical atmospheric levels (5., 10., 20., 30., 50., 70., 100., 150., 200., 250., 300., 400., 500., 620., 700., 780., 850., 920., 950., 1000. mbar) The water vapor parameter is an estimate of the total tropospheric column water vapor made from integrated MODIS infrared retrievals of atmospheric moisture profiles in clear scenes. The thermal band 9.6 micron is used for retrieving total ozone burden. The shortname for this Level-2 MODIS atmospheric profile product is MYD07_L2 and the principal investigator for this product is MODIS scientist Dr. Paul Menzel ( paulm@ssec.wisc.edu).The MODIS atmospheric profile (MYD07_L2) product contains data that has a spatial resolution (pixel size) of 5 x 5 kilometers (at nadir). Each MYD07_L2 product file covers a five-minute time interval, which means the MYD07_L2 output grid is 270 5-km pixels in width and 406 5-km pixels in length for nine consecutive granules. Every tenth granule has an output grid size of 270 by 408 pixels. MYD07_L2 product files are stored in Hierarchical Data Format(HDF-EOS). Twenty eight of the 30 gridded cloud parameters(5-kilometer pixel resolution) are stored as Scientific Data Sets (SDS) within the file, the remaining two algorithmic static parameters (band number and presure level) are stored as Vdata(table arrays). Cloud Mask SDS, derived from the 1-km MOD35_L2 Cloud Mask parameter, is remapped to 5-km resolution, by using only the center 1-km pixel in the 5x5 pixel retrieval array. The remaining two (band number and static pressure levels) are stored as Vdata(table arrays) Each file is roughly 8 MB in size, and the total data volume is approximately 2 GB/day. MYD07_L2 Data Group and Parameters: Spatial &amp; Temporal Resolution:Latitude &amp; LongitudeScan start time Solar and Sensor Viewing Geometry:Solar zenith &amp; Solar azimuth angleSensor zenith &amp; Sensor azimuth angle Static Algorithm Parameters:MODIS band numberPressure levels Atmospheric &amp; Surface Pressure:Retrieved Geopotential Height ProfileTropopause HeightSurface Elevation, Surface Pressure Atmospheric &amp; Surface Temperature:Guess &amp; Retrieved Temperature ProfilesBrightness Temperature and Skin Temperature Atmospheric Moisture:Guess Mixing ratio ProfileRetrieved Dew Point Temperature Profile Atmospheric Stability Indices:Total Totals, Lifted Index, and K-index Atmospheric Trace Gases:Total Ozone BurdenTotal Column Precipitable Water Vapor - IR RetrievalTotal Column Precipitable Water Vapor - Direct IR RetrievalWater Vapor(Low &amp; High)Retrieved Water Vapour Mixing Ratio Profile Quality Assurance &amp; Statistical Parameters:Quality Assurance ParametersRun time QA flagsMODIS Cloud MaskProcessing Flag These parameters are very essential in the characterization of the atmosphere, atmospheric correction of remotely sensed surface parameters, and prediction of convective clouds and thunderstorms. For more information about the MYD07_L2 product, visit the MODIS-Atmosphere site at:http://modis-atmos.gsfc.nasa.gov/MOD07_L2/

AIRS/Aqua L1B Near Real Time (NRT) AMSU (A1/A2) geolocated and calibrated brightness temperatures V005 (AIRABRAD_NRT) at GES DISC

The AMSU-A Level 1B Near Real Time (NRT) product (AIRABRAD_NRT_005) differs from the routine product (AIRABRAD_005) in 2 ways to meet the three hour latency requirements of the Land Atmosphere NRT Capability Earth Observing System (LANCE): (1) The NRT granules are produced without previous or subsequent granules if those granules are not available within 5 minutes, (2) the predictive ephemeris/attitude data are used rather than the definitive ephemeris/attitude. The consequences of these differences are described in the AIRS Near Real Time (NRT) data products document. The Atmospheric Infrared Sounder (AIRS) is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors. The AMSU-A instrument is co-aligned with AIRS so that successive blocks of 3 x 3 AIRS footprints are contained within one AMSU-A footprint. AMSU-A is primarily a temperature sounder that provides atmospheric information in the presence of clouds, which can be used to correct the AIRS infrared measurements for the effects of clouds. This is possible because non-precipitating clouds are for the most part transparent to microwave radiation, in contrast to visible and infrared radiation which are strongly scattered and absorbed by clouds. AMSU-A1 has 13 channels from 50 - 90 GHz and AMSU-A2 has 2 channels from 23 - 32 GHz. The AIRABRAD_NRT_005 products are stored in files (often referred to as "granules") that contain 6 minutes of data, 30 footprints across track by 45 lines along track.

MLS/Aura Near-Real-Time L2 Carbon Monoxide (CO) Mixing Ratio V005 (ML2CO_NRT) at GES DISC

ML2CO_NRT is the EOS Aura Microwave Limb Sounder (MLS) Near-Real-Time (NRT) product for carbon monoxide (CO). This product contains CO profiles derived from the 240 GHz region. The NRT data are typically available within 3 hours of observation and are broken into files containing about 15 minutes of data. The most recent 7 days of data are available online. Spatial coverage is near-global (-82 degrees to +82 degrees latitude), with each profile spaced 1.5 degrees or ~165 km along the orbit track (roughly 15 orbits per day). The vertical coverage is from 215 to 0.1 hPa. The MLS NRT algorithm uses a simplified fast forward model to meet Near Real Time data latency requirements and are therefore not as accurate as the retrievals that constitute the standard MLS products. Nevertheless the results are scientifically useful in selected regions of the Earth's atmosphere provided that the data are screened according to the recommendations in the MLS NRT User Guide and the MLS L2 Data Quality Document for Standard Products.

AIRS/Aqua L1B Near Real Time (NRT) Infrared (IR) geolocated and calibrated radiances V005 (AIRIBRAD_NRT) at GES DISC

WARNING: On 2021/09/23 the EOS Aqua executed a Deep Space Maneuver (DSM). In the DSM, the spacecraft is turned such that the normal Earth field of regard is deep space. The thermal impact of the DSM caused a shift of the centroids of spectral response functions (SRF) of about 1% of the width of the SRF, equivalent to a frequency shift of 9 parts per million. This shift is reflected in the “spectral_freq” parameter (observed frequencies) in the L1b v5 files for each 6 minute granule. The magnitude of the effect on brightness temperatures (BT) depends on the spectral gradient of each channel. Maximum BT shifts are approximately +- 0.5 K, although many channels experience far smaller BT shifts. Approximately 1803 channels have BT shifts of less than 0.1 K and 575 channels are now shifted in BT by more than 0.1 K, while 231 of these channels have BT shifts greater than 0.2 K. Users of the L1b v5 product who are concerned that these shifts may impact their science investigations and applications are encouraged to switch to the AIRS L1c v6.7.4 product, which, among many other improvements, converts the spectra to a fixed frequency grid. END OF WARNING. The AIRS Level 1B Near Real Time (NRT) product (AIRIBRAD_NRT_005) differs from the routine product (AIRIBRAD_005) in 2 ways to meet the three hour latency requirements of the Land Atmosphere NRT Capability Earth Observing System (LANCE): (1) The NRT granules are produced without previous or subsequent granules if those granules are not available within 5 minutes, (2) the predictive ephemeris/attitude data are used rather than the definitive ephemeris/attitude. The consequences of these differences are described in the AIRS Near Real Time (NRT) data products document. The Atmospheric Infrared Sounder (AIRS) is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors. The AIRS Infrared (IR) level 1B data set contains AIRS calibrated and geolocated radiances in milliWatts/m^2/cm^-1/steradian for 2378 infrared channels in the 3.74 to 15.4 micron region of t he spectrum. The AIRS instrument is co-aligned with AMSU-A so that successive blocks of 3 x 3 AIRS footprints are contained within one AMSU-A footprint. The AIRIBRAD_NRT_005 products are stored in files (often referred to as "granules") that contain 6 minutes of data, 90 footprints across track by 135 lines along track.

MODIS/Terra Near Real Time (NRT) Calibrated Radiances 5-Min L1B Swath 500m

The 500 meter MODIS Level 1B Near Real Time (NRT) data set contains calibrated and geolocated at-aperture radiances for 7 discrete bands located in the 0.45 to 2.20 micron region of the electromagnetic spectrum. These data are generated from the MODIS Level 1A scans of raw radiance and in the process converted to geophysical units of W/(m^2 um sr). In addition, the Earth Bi-directional Reflectance Distribution Function (BRDF) may be determined for these solar reflective bands through knowledge of the solar irradiance (e.g., determined from MODIS solar diffuser data, and from the target illumination geometry). Additional data are provided including quality flags, error estimates and calibration data. Visible, shortwave infrared, and near infrared measurements are only made during the daytime, while radiances for the thermal infrared region (bands 20-25, 27-36) are measured continuously. Channel locations for the MODIS 500 meter data are as follows: Band Center Wavelength (um) Primary Use ---- ---------------------- ----------- 1 0.620 - 0.670 Land/Cloud Boundaries 2 0.841 - 0.876 Land/Cloud Boundaries 3 0.459 - 0.479 Land/Cloud Properties 4 0.545 - 0.565 Land/Cloud Properties 5 1.230 - 1.250 Land/Cloud Properties 6 1.628 - 1.652 Land/Cloud Properties 7 2.105 - 2.155 Land/Cloud Properties Channels 1 and 2 have 250 m resolution, channels 3 through 7 have 500 m resolution. However, for the MODIS L1B 500 m product, the 250 m band radiance data and their associated uncertainties have been aggregated to 500 m resolution. Thus the entire channel data set has been co-registered to the same spatial scale in the 500 m product. Separate L1B products are available for the 250 m resolution channels (MOD02QKM) and 1 km resolution channels (MOD021KM). For the latter product, the 250 m and 500 m channel data (bands 1 through 7) have been aggregated into equivalent 1 km pixel values. Spatial resolution for pixels at nadir is 500 km, degrading to 2.4 km in the along-scan direction at the scan extremes. However, thanks to the overlapping of consecutive swaths and respectively pixels there, the resulting resolution at the scan extremes is about 1 km. A 55 degree scanning pattern at the EOS orbit of 705 km results in a 2330 km orbital swath width and provides global coverage every one to two days. A single MODIS Level 1B 500 m granule will contain a scene built from 203 scans sampled 2708 times in the cross-track direction, corresponding to approximately 5 minutes worth of data; thus 288 granules will be produced per day. Since an individual MODIS scan will contain 20 along-track spatial elements for the 500 m channels, the scene will be composed of (2708 x 4060) pixels, resulting in a spatial coverage of (2330 km x 2040 km). Due to the MODIS scan geometry, there will be increasing scan overlap beyond about 20 degrees scan angle. To summarize, the MODIS L1B 500 m data product consists of: 1. Calibrated radiances, uncertainties and number of samples for (2) 250 m reflected solar bands aggregated to 500 m resolution 2. Calibrated radiances and uncertainties for (5) 500 m reflected solar bands 3. Geolocation for 1km pixels, that must be interpolated to get 500 m pixel locations. For the relationship of 1km pixels to 500m pixels, see the Geolocation ATBD http://modis.gsfc.nasa.gov/data/atbd/atbd_mod28_v3.pdf . 4. Calibration data for all channels (scale and offset) 5. Comprehensive set of file-level metadata summarizing the spatial, temporal and parameter attributes of the data, as well as auxiliary information pertaining to instrument status and data quality characterization The MODIS L1B 500 m data are stored in the Earth Observing System Hierarchical Data Format (HDF-EOS) which is an extension of HDF as developed by the National Center for Supercomputer Applications (NCSA) at the University of Illinois. A typical file size will be approximately 170 MB. Environmental information derived from MODIS L1B measurements will offer a comprehensive and unprecedented look at terrestrial, atmospheric, and ocean phenomenology for a wide and diverse community of users throughout the world. The Shortname for this product is MOD02HKM

MODIS/Terra Near Real Time (NRT) Surface Reflectance Daily L2G Global 250m SIN Grid

The MODIS Near Real Time (NRT) Surface Reflectance products are an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption. Low-level data are corrected for atmospheric gases and aerosols, yielding a level-2 basis for several higher-order gridded level-2 (L2G) and level-3 products. MOD09GQ provides Bands 1 and 2 at a 250-meter resolution in a daily gridded L2G product in the Sinusoidal projection. Science Data Sets provided for this product include reflectance for Bands 1 and 2 a quality rating observation coverage and observation number. This product is meant to be used in conjunction with MOD09GA where important quality and viewing geometry information is stored.Additional information at LPDAAC:https://lpdaac.usgs.gov/dataset_discovery/modis/modis_products_table

Sentinel-5P TROPOMI Near-Real-Time (NRT) Radiance product band 5 (NIR detector) L1B 5.5km x 3.5km V2 (S5P_L1B_RA_BD5_HiR_NRT) at GES DISC

The Sentinel-5P TROPOMI Near Real Time (NRT) Radiance product band 5 (NIR detector) L1B 5.5km x 21km V2 (S5P_L1B_RA_BD5_HiR_NRT) product at GES DISC is the near real time version of the offline S5P_L1B_RA_BD4_HiR data product. These data are typically available within three hours of measurement as required by the Land Atmosphere NRT Capability Earth Observing System (LANCE). These data are intended for a rapid turnaround assessment and are only archived for up to ten days. Users who require a longer data record, or wish to conduct rigorous analysis should use the offline version of this product S5P_L1B_RA_BD5_HiR. The Copernicus Sentinel-5 Precursor (Sentinel-5P or S5P) satellite mission is one of the European Space Agency's (ESA) new mission family - Sentinels, and it is a joint initiative between the Kingdom of the Netherlands and the ESA. The sole payload on Sentinel-5P is the TROPOspheric Monitoring Instrument (TROPOMI), which is a nadir-viewing 108 degree Field-of-View push-broom grating hyperspectral spectrometer, covering the wavelength of ultraviolet-visible (UV-VIS, 270nm to 495nm), near infrared (NIR, 675nm to 775nm), and shortwave infrared (SWIR, 2305nm-2385nm). TROPOMI Level-1B (L1B) product is generated by the Koninklijk Nederlands Meteoroligisch Instituut (KNMI) TROPOMI L01B processor from Level-0 input data and auxiliary data products with the netCDF-4 enhanced model. It provides users with radiance, irradiance, calibration and engineering products. Data are stored in individual files, or granules, that contain one orbit of information. The data are stored in netCDF4 data format and files and complete files are ~0.650 GB.

MODIS/Terra Near Real Time (NRT) Snow Cover 5-Min L2 Swath 500m, Version 6

MODIS/Terra Near Real Time (NRT) Snow Cover 5-Min L2 Swath 500m (MOD10_L2) contains snow cover and quality assurance (QA) data, latitudes, and longitudes in HDF-EOS format, along with corresponding metadata. Latitude and longitude geolocation fields are at 5 km resolution, while all other fields are at 500 m resolution. Version 5 (V005) has two separate snow cover fields: one incorporating the original cloud mask, and another using a less cloud-conservative mask. MODIS/Terra V005 data extend from 24 February 2000 to present. MODIS snow cover data are based on a snow mapping algorithm that employs a Normalized Difference Snow Index (NDSI) and other criteria tests. The only data available for Version 5 (V005) is the Golden Month, which is a sample of V004 data covering the time period 29 August 2002 (day of year 241) through 7 October 2002 (day of year 280). The Golden Month is only available by special request by contacting NSIDC User Services. Please note that NSIDC now has a complete series of Version 5 data, which is the highest version number now available and represents the best quality of data.

AIRS/Aqua L2 Near Real Time (NRT) Support Retrieval (AIRS-only) V006 (AIRS2SUP_NRT) at GES DISC

The Atmospheric Infrared Sounder (AIRS) Level 2 Near Real Time (NRT) Support Retrieval (AIRS-only) product (AIRS2SUP_NRT_006) differs from the routine product (AIRS2SUP_006) in four ways to meet the three hour latency requirements of the Land Atmosphere NRT Capability Earth Observing System (LANCE): (1) The NRT granules are produced without previous or subsequent granules if those granules are not available within 5 minutes, (2) the predictive ephemeris/attitude data are used rather than the definitive ephemeris/attitude, (3) if the forecast surface pressure is unavailable, a surface climatology is used, and (4) no ice cloud properties retrievals are performed. The consequences of these differences are described in the AIRS Near Real Time (NRT) data products document. The Atmospheric Infrared Sounder (AIRS) is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors. This product is product produced using AIRS IR only because the radiometric noise in AMSU channel 4 started to increase significantly (since June 2007). The Support Product includes higher vertical resolution profiles of the quantities found in the Standard Product, plus intermediate outputs (e.g., microwave-only retrieval), research products such as the abundance of trace gases, and detailed quality assessment information. The Support Product profiles contain 100 levels between 1100 and .016 mb; this higher resolution simplifies the generation of radiances using forward models, though the vertical information content is no greater than that in the Standard Product profiles. The intended users of the Support Product are researchers interested in generating forward radiance or in examining research products, and the AIRS algorithm development team. The Support Product is generated at all locations as Standard Products. An AIRS granule has been set as 6 minutes of data, 30 footprints cross track by 45 scanlines. There are 240 granules per day, with an orbit repeat cycle of approximately 16 day.

MODIS/Terra Near Real Time (NRT) Surface Reflectance Rolling-8-Day L3 Global 500m SIN Grid

The MODIS Near Real Time (NRT) product, MOD09A1N provides Bands 1-7 at 500-meter resolution in a daily rolling 8-day gridded level-3 product in the Sinusoidal projection. Each MOD09A1N pixel contains the best possible L2G observation during an 8-day period as selected on the basis of high observation coverage, low view angle, the absence of clouds or cloud shadow, and aerosol loading. Science Data Sets provided for this product include reflectance values for Bands 1-7, quality assessment, and the day of the year for the pixel along with solar, view, and zenith angles.

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Ground-Based Global Navigation Satellite System (GNSS)-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN) Near Real-Time Ionospheric Total Electron Count (5-second sampling, 24-hour files) from NASA CDDIS

Developed at JPL, GUARDIAN is a near-real-time (NRT) ionospheric monitoring software (Martire et al.). Its main products are NRT total electronic content (TEC) time series, allowing users to explore ionospheric TEC perturbations due to natural and anthropogenic events on Earth. The NRT GUARDIAN time series are validated against well-established post-processing methods. Currently, time series are computed for more than 90 GNSS ground stations distributed around the Pacific Ring of Fire, which monitor the four main GNSS constellations (GPS, Galileo, BDS, and GLONASS).

MODIS/Aqua Near Real Time (NRT) Cloud Mask and Spectral Test Results 5-Min L2 Swath 250m and 1km

The MODIS level-2 cloud mask product is a global product generated for both daytime & nighttime conditions at 1-km spatial resolution (at nadir) and for daytime at 250-m resolution. The algorithm employs a series of visible and infrared threshold and consistency tests to specify confidence levels that an unobstructed view of the Earth's surface is observed. An indication of shadows affecting the scene is also provided. The 250-m cloud mask flags are based on the visible channel data only. Radiometrically accurate radiances are required, so holes in the cloud mask will appear wherever the input radiances are incomplete or of poor quality. The shortname for this Level-2 MODIS cloud mask product is MYD35_L2 and the principal investigator for this product is MODIS scientist Dr. Paul Menzel ( paulm@ssec.wisc.edu). MYD35_L2 product files are stored in Hierarchical Data Format (HDF-EOS). Each of the 9 gridded parameters is stored as a Scientific Data Set (SDS) within the HDF-EOS file. The Cloud Mask and Quality Assurance SDS's are stored at 1 kilometer pixel resolution. All other SDS's (those relating to time, geolocation, and viewing geometry) are stored at 5 kilometer pixel resolution. MYD35_L2 Data Group & Parameters Spatial & Temporal Resolution: Latitude & Longitude Scan start time Solar and Sensor Viewing Geometry: Solar zenith & Solar azimuth angle Sensor zenith & Sensor azimuth angle Science Parameters Cloud Mask (1km) Cloud Mask (250 m) Quality Assurance Parameters: Quality Assurance Flags (1km) Link to the MODIS homepage for more data set information: http://modis-atmos.gsfc.nasa.gov/MOD35_L2/

Global Navigation Satellite System (GNSS) IGS Decoded Orbit Solution (30-second) from IGS Real-Time Product Streams from NASA CDDIS

This derived product set consists of Global Navigation Satellite System satellite orbit products (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.These orbit products are 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. The product streams are combination solutions generated by processing individual real time solutions from participating IGS Real-time Analysis Centers (ACs). The effect of combining the different AC solutions is a more reliable and stable performance than that of any single AC's product. This derived product solution is one of the RTS solutions generated by decoding the real-time product streams. These files use the real-time data streams that are referred to the satellite center-of-mass (CoM). These orbit products have been provided in support of the IGS Real-Time Service (previously Real-Time Pilot Project) since February 2009, prior to the availability of real-time product streams. This combination is a daily solution available approximately one to three days after the end of the previous UTC day. All orbit solution files utilize the SP3 format and span 24 hours from 00:00 to 23:45 UTC.

MODIS/Terra Near Real Time (NRT) Calibrated Radiances 5-Min L1B Swath 1km

The MODIS Level 1B Near Real Time (NRT) data set contains calibrated and geolocated at-aperture radiances for 36 discrete bands located in the 0.4 to 14.4 micron region of electromagentic spectrum. These data are generated from the MODIS Level 1A scans of raw radiance and in the process converted to geophysical units of W/(m^2 um sr). In addition, the Earth Bi-directional Reflectance Distribution Function (BRDF) may be determined for the solar reflective bands (1-19, 26) through knowledge of the solar irradiance (e.g., determined from MODIS solar diffuser data, and from the target illumination geometry). Additional data are provided including quality flags, error estimates and calibration data. Visible, shortwave infrared, and near infrared measurements are only made during the daytime, while radiances for the thermal infrared region (bands 20-25, 27-36) are measured continuously. Channel locations for MODIS are as follows: Band Center Wavelength (um) Primary Use---- ---------------------- -----------1 0.620 - 0.670 Land/Cloud Boundaries2 0.841 - 0.876 Land/Cloud Boundaries3 0.459 - 0.479 Land/Cloud Properties4 0.545 - 0.565 Land/Cloud Properties5 1.230 - 1.250 Land/Cloud Properties6 1.628 - 1.652 Land/Cloud Properties7 2.105 - 2.155 Land/Cloud Properties8 0.405 - 0.420 Ocean Color/Phytoplankton9 0.438 - 0.448 Ocean Color/Phytoplankton10 0.483 - 0.493 Ocean Color/Phytoplankton11 0.526 - 0.536 Ocean Color/Phytoplankton12 0.546 - 0.556 Ocean Color/Phytoplankton13 0.662 - 0.672 Ocean Color/Phytoplankton14 0.673 - 0.683 Ocean Color/Phytoplankton15 0.743 - 0.753 Ocean Color/Phytoplankton16 0.862 - 0.877 Ocean Color/Phytoplankton17 0.890 - 0.920 Atmospheric Water Vapor18 0.931 - 0.941 Atmospheric Water Vapor19 0.915 - 0.965 Atmospheric Water Vapor20 3.660 - 3.840 Surface/Cloud Temperature21 3.929 - 3.989 Surface/Cloud Temperature22 3.929 - 3.989 Surface/Cloud Temperature23 4.020 - 4.080 Surface/Cloud Temperature24 4.433 - 4.498 Atmospheric Temperature25 4.482 - 4.549 Atmospheric Temperature26 1.360 - 1.390 Cirrus Clouds27 6.535 - 6.895 Water Vapor Profile28 7.175 - 7.475 Water Vapor Profile29 8.400 - 8.700 Water Vapor Profile30 9.580 - 9.880 Ozone Overburden31 10.780 - 11.280 Surface/Cloud Temperature32 11.770 - 12.270 Surface/Cloud Temperature33 13.185 - 13.485 Cloud Top Altitude34 13.485 - 13.785 Cloud Top Altitude35 13.785 - 14.085 Cloud Top Altitude36 14.085 - 14.385 Cloud Top Altitude Channels 1 and 2 have 250 m resolution, channels 3 through 7 have 500m resolution, and the rest have 1 km resolution. However, for the MODIS L1B 1 km product, the 250 m and 500 m band radiance data and their associated uncertainties have been aggregated to 1km resolution. Thus the entire channel data set is referenced to the same spatial and geolocation scales. Separate L1B products are available for the 250 m channels (MOD02QKM) and 500 m channels (MOD02HKM) that preserve the original resolution of the data. Spatial resolution for pixels at nadir is 1 km, degrading to 4.8 km in the along-scan direction at the scan extremes. However, thanks to the overlapping of consecutive swaths and respectively pixels there, the resulting resolution at the scan extremes is about 2km. A 55 degree scanning pattern at the EOS orbit of 705 km results in a 2330km orbital swath width and provides global coverage every one to two days. A single MODIS Level 1B granule will nominally contain a scene built from 203 scans (or swaths) sampled 1354 times in the cross-track direction, corresponding to approximately 5 minutes worth of data. Since an individual MODIS scan (or swath) will contain 10 along-track spatial elements, the scene will be composed of (1354 x 2030) pixels, resulting in a spatial coverage of (2330 km x 2030 km). Due to the MODIS scan geometry, there will be increasing overlap occurring beyond about 25 degrees scan angle. To summarize, the MODIS L1B 1 km data product consists of: 1. Calibrated radiances and uncertainties for (2) 250 m reflected solar bands aggregated to 1km resolution 2. Calibrated radiances and uncertainties for (5) 500 m reflected solar bands aggregat

MODIS/Terra Near Real Time (NRT) Clouds 5-Min L2 Swath 1km and 5km

The level-2 MODIS cloud product consists of cloud optical and physical parameters. These parameters are derived using remotely sensed infrared, visible and near infrared solar reflected radiances. MODIS infrared channel radiances are used to derive cloud top temperature, cloud top height, effective emissivity, cloud phase (ice vs. water, opaque vs. non-opaque), and cloud fraction under both daytime and nighttime conditions. MODIS visible radiances are used to derive cloud optical thickness and effective particle radius and cloud shadow effects. Near infrared solar reflected radiance provides additional information in the retrieval of cloud particle phase (ice vs. water, clouds vs. snow). The shortname for this level-2 MODIS cloud product is MOD06_L2.MOD06_L2 consists of parameters at a spatial resolution of either 1- km or 5-km (at nadir). Each MOD06_L2 product file covers a five-minute time interval. This means that for 5-km resolution parameters, the output grid is 270 pixels in width by 406 pixels in length. Every tenth granule has an output grid size of 270 by 408 pixels. For 1-km resolution parameters, the output grid is 1354 pixels in width by 2030 pixels in length and every tenth granule has an output grid size of 1354 by 2040 pixels.MOD06_L2 product files are stored in Hierarchical Data Format (HDF-EOS). All gridded cloud parameters are stored as Scientific Data Sets (SDS) within the file, except two (band number and statistics). These are stored as Vdata(table arrays). Approximately 288 files are produced daily. Nighttime files are smaller than their daytime counterparts since only cloud top properties are retrieved at night.The Collection 6 cloud-top property product changes include new 1 km SDSs in addition to the legacy 5 km SDSs, and a new physical cloud height dataset. New 1 km products include cloud top pressure, IR cloud emissivity, cloud height, overshooting cloud top flag, and cloud phase. The 1 km IR phase product is generated using an updated algorithm while the other 1 km products were designed to be as similar as possible to the 5 km version.And, the Collection 6 Cloud optical/microphysical product changes include expanded/improved pixel-level retrieval uncertainty calculations that are intended to be used in lieu of retrieval QA assignments that are no longer assigned (legacy QA bits are now set to a value of 3 for all successful retrievals). Retrievals are now attempted on a pixel flagged as likely to have a partly cloudy field of view by the so-called clear sky restoral algorithm introduced in C5 processing. Successful retrievals from this pixel population have similar SDS names as the non-flagged pixel population but with ???_PCL??? (for Partly CLoudy) appended to the end of the parameter name; an exception is the uncertainty SDSs where both PCL and non-PCL retrieval uncertainties are kept. Metrics for unsuccessful retrievals (those outside the look-up table solution space) are now provided as well (Retrieval_Failure_Metric_*). Finally, absolute retrievals are provided for the other visible and near-infrared (VNIR) and shortwave infrared band pairs (VNIR and 1.6 ??m, VNIR and 3.7 ??m) instead of as differences relative to the VNIR/2.1 ??m retrieval. For more details regarding dataset changes read the document at http://modis-atmos.gsfc.nasa.gov/products_C006update.html.MOD06_L2 Data Category & ParametersSpatial and Temporal Resolution:latitude,longitudescan start timeSolar and Sensor Viewing Geometry:Solar_Azimuth(daytime,nighttime,all), Solar_Zenith(daytime,nighttime,all), Sensor_Azimuth(daytime,nighttime,all), Sensor_Zenith(daytime,nighttime,all)Cloud Top Parameters (5km):Cloud_Effective_Emissivity_(Day, Night, Nadir, Nadir_Day,Nadir_Night, All), Cloud_Fraction_(Day, Night, Nadir, Nadir_Day,Nadir_Night, All), Cloud_Height_Method, Cloud_Phase_Infrared_(day, night, all), Cloud_Top_Height_(Day, Night, Nadir, Nadir_Day,Nadir_Night, All), cloud_top_method_1km, Cloud_Top_Pressure_From_Ratios, Cloud_Top_Pressure_Infrared, Cloud_Top_Pressure_(Day, Night, Nadir, Nadir_Day,Nadir_Night, All), Cloud_Top_Temperature_(Day, Night, Nadir, Nadir_Day,Nadir_Night, All)Cloud Top Parameters (1km):cloud_top_height_1km, cloud_top_pressure_1km, cloud_top_temperature_1km, , cloud_emiss(11, 12, 13, 85, All)_1km, IRW_Low_Cloud_Temperature_From_COPCloud Optical Properties (1km):Above_Cloud_Water_Vapor_094, Cloud_Effective_Radius_(PCL, 16, 16_PCL,1621, 1621_PCL,37,37_PCL, All) , Cloud_Optical_Thickness_(PCL, 16, 16_PCL,1621, 1621_PCL,37,37_PCL, All), Cloud_Phase_Infrared_1km, Cloud_Phase_Optical_Properties, Cloud_Water_Path_(PCL, 16, 16_PCL,1621, 1621_PCL,37,37_PCL, All)Radiation Parameters:Radiance_Variance, Brightness_Temperature, Spectral_Cloud_Forcing, Surface_Pressure, Surface_Temperature, surface_temperature_1km, Atm_Corr_Refl, Cirrus_ReflectanceQuality Assurance Parameters:Processing flag for 5 km resolution, Cloud_Multi_Layer_Flag, cirrus reflectance flag for 1 km resolution, quality assurance flag f

Global Navigation Satellite System (GNSS) IGS Decoded Clock Solution (10-second) from IGS Real-Time Product Streams from NASA CDDIS

This derived product set consists of Global Navigation Satellite System satellite and receiver clock products (10-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. These clock products are 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. The product streams are combination solutions generated by processing individual real time solutions from participating IGS Real-time Analysis Centers (ACs). The effect of combining the different AC solutions is a more reliable and stable performance than that of any single AC's product. This derived product solution is one of the RTS solutions generated by decoding the real-time product streams. These files use the real-time data streams that are referred to the satellite center-of-mass (CoM). These clock products have been provided in support of the IGS Real-Time Service (previously Real-Time Pilot Project) since February 2009, prior to the availability of real-time product streams. 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.

MODIS/Aqua Near Real Time (NRT) Calibrated Radiances 5-Min L1B Swath 500m

The 500 meter MODIS Level 1B Near Real Time (NRT) data set contains calibrated and geolocated at-aperture radiances for 7 discrete bands located in the 0.45 to 2.20 micron region of the electromagnetic spectrum. These data are generated from the MODIS Level 1A scans of raw radiance and in the process converted to geophysical units of W/(m^2 um sr). In addition, the Earth Bi-directional Reflectance Distribution Function (BRDF) may be determined for these solar reflective bands through knowledge of the solar irradiance (e.g., determined from MODIS solar diffuser data, and from the target illumination geometry). Additional data are provided including quality flags, error estimates and calibration data. Visible, shortwave infrared, and near infrared measurements are only made during the daytime, while radiances for the thermal infrared region (bands 20-25, 27-36) are measured continuously. Channel locations for the MODIS 500 meter data are as follows: Band Center Wavelength (um) Primary Use ---- ---------------------- ----------- 1 0.620 - 0.670 Land/Cloud Boundaries 2 0.841 - 0.876 Land/Cloud Boundaries 3 0.459 - 0.479 Land/Cloud Properties 4 0.545 - 0.565 Land/Cloud Properties 5 1.230 - 1.250 Land/Cloud Properties 6 1.628 - 1.652 Land/Cloud Properties 7 2.105 - 2.155 Land/Cloud Properties Channels 1 and 2 have 250 m resolution, channels 3 through 7 have 500 m resolution. However, for the MODIS L1B 500 m product, the 250 m band radiance data and their associated uncertainties have been aggregated to 500 m resolution. Thus the entire channel data set has been co-registered to the same spatial scale in the 500 m product. Separate L1B products are available for the 250 m resolution channels (MYD02QKM) and 1 km resolution channels (MYD021KM). For the latter product, the 250 m and 500 m channel data (bands 1 through 7) have been aggregated into equivalent 1 km pixel values. Spatial resolution for pixels at nadir is 500 km, degrading to 2.4 km in the along-scan direction at the scan extremes. However, thanks to the overlapping of consecutive swaths and respectively pixels there, the resulting resolution at the scan extremes is about 1 km. A 55 degree scanning pattern at the EOS orbit of 705 km results in a 2330 km orbital swath width and provides global coverage every one to two days. A single MODIS Level 1B 500 m granule will contain a scene built from 203 scans sampled 2708 times in the cross-track direction, corresponding to approximately 5 minutes worth of data; thus 288 granules will be produced per day. Since an individual MODIS scan will contain 20 along-track spatial elements for the 500 m channels, the scene will be composed of (2708 x 4060) pixels, resulting in a spatial coverage of (2330 km x 2040 km). Due to the MODIS scan geometry, there will be increasing scan overlap beyond about 20 degrees scan angle. To summarize, the MODIS L1B 500 m data product consists of: 1. Calibrated radiances, uncertainties and number of samples for (2) 250 m reflected solar bands aggregated to 500 m resolution 2. Calibrated radiances and uncertainties for (5) 500 m reflected solar bands 3. Geolocation for 1km pixels, that must be interpolated to get 500 m pixel locations. For the relationship of 1km pixels to 500m pixels, see the Geolocation ATBD http://modis.gsfc.nasa.gov/data/atbd/atbd_mod28_v3.pdf . 4. Calibration data for all channels (scale and offset) 5. Comprehensive set of file-level metadata summarizing the spatial, temporal and parameter attributes of the data, as well as auxiliary information pertaining to instrument status and data quality characterization The MODIS L1B 500 m data are stored in the Earth Observing System Hierarchical Data Format (HDF-EOS) which is an extension of HDF as developed by the National Center for Supercomputer Applications (NCSA) at the University of Illinois. A typical file size will be approximately 170 MB. Environmental information derived from MODIS L1B measurements will offer a comprehensive and unprecedented look at terrestrial, atmospheric, and ocean phenomenology for a wide and diverse community of users throughout the world. The Shortname for this product is MYD02HKM