MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am equator crossing time) as part of NASA's Earth Observing System (EOS) mission. MODIS with its 2330 km viewing swath width provides almost daily global coverage. It acquires data in 36 high spectral resolution bands between 0.415 to 14.235 micron with spatial resolutions of 250m(2 bands), 500m(5 bands),and 1000m (29 bands). MODIS sensor counts, calibrated radiances, geolocation products and all derived geophysical atmospheric and ocean products are archived at various DAACs and has been made available to public since April 2000. The shortname for this level-3 MODIS aerosol product is MCDAODHD. The Naval Research Laboratory and the University of North Dakota developed this value-added aerosol optical depth dataset based on MODIS Level 2 aerosol products. MCDAODHD is a gridded product and is specifically designed for quantitative applications including data assimilation and model validation. It is available through LANCE-MODIS. It offers several enhancements over the MODIS Level 2 data on which it is based. These enhancements include stringent filtering to reduce outliers, eliminate cloud contamination, and exclude conditions where aerosol detection is likely to be inaccurate; reduction of systematic biases over land and ocean by empirical corrections; reduction of random variation in AOD values by spatial averaging; quantitative estimation of uncertainty for each AOD data point. The MxDAODHD granules are produced every six hours, and time-stamped 00:00, 06:00, 12:00, and 18:00 (all times UTC). Each granule includes MODIS observations from +/-3 hours from the timestamp (e.g. 12:00 product includes MODIS data from 09:00-15:00 UTC). Production is initiated as soon as the Level 2 inputs become available in the LANCE system. See the LANCE-MODIS page for more dataset information: https://earthdata.nasa.gov/earth-observation-data/near-real-time/download-nrt-data/modis-nrt

MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am equator crossing time) as part of NASA's Earth Observing System (EOS) mission. MODIS with its 2330 km viewing swath width provides almost daily global coverage. It acquires data in 36 high spectral resolution bands between 0.415 to 14.235 micron with spatial resolutions of 250m(2 bands), 500m(5 bands),and 1000m (29 bands). MODIS sensor counts, calibrated radiances, geolocation products and all derived geophysical atmospheric and ocean products are archived at various DAACs and has been made available to public since April 2000. The shortname for this level-3 MODIS aerosol product is MYDAODHD. The Naval Research Laboratory and the University of North Dakota developed this value-added aerosol optical depth dataset based on MODIS Level 2 aerosol products. The MYDAODHD is a gridded product and is specifically designed for quantitative applications including data assimilation and model validation. It is available through LANCE-MODIS. It offers several enhancements over the MODIS Level 2 data on which it is based. These enhancements include stringent filtering to reduce outliers, eliminate cloud contamination, and exclude conditions where aerosol detection is likely to be inaccurate; reduction of systematic biases over land and ocean by empirical corrections; reduction of random variation in AOD values by spatial averaging; quantitative estimation of uncertainty for each AOD data point. The MxDAODHD granules are produced every six hours, and time-stamped 00:00, 06:00, 12:00, and 18:00 (all times UTC). Each granule includes MODIS observations from +/-3 hours from the timestamp (e.g. 12:00 product includes MODIS data from 09:00-15:00 UTC). Production is initiated as soon as the Level 2 inputs become available in the LANCE system. See the LANCE-MODIS page for more dataset information: https://earthdata.nasa.gov/earth-observation-data/near-real-time/download-nrt-data/modis-nrt

The MODIS/Terra Aerosol Optical Thickness Daily L3 Global 0.05Deg CMA Neal Real Time (NRT) Product (MOD09CMA) is a daily level 3 and global product. It is in linear latitude and longitude (Plate Carre) projection with a 0.05Deg spatial resolution. This product is derived from MOD09IDN, MOD09IDT and MOD09IDS for each orbit by compositing the data on the basis of minimum band 3 (459 - 479 nm band) values (after excluding pixels flagged for clouds and high solar zenith angles).

The MCD19A2 Version 6.1 data product is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Multi-angle Implementation of Atmospheric Correction (MAIAC) Land Aerosol Optical Depth (AOD) gridded Level 2 product produced daily at 1 kilometer (km) pixel resolution. The MCD19A2 product provides the atmospheric properties and view geometry used to calculate the MAIAC Land Surface Bidirectional Reflectance Factor (BRF) or surface reflectance, MCD19A1 product. The MCD19A2 AOD data product contains the following Science Dataset (SDS) layers: blue band AOD at 0.47 µm, green band AOD at 0.55 µm, AOD uncertainty, fine mode fraction over water, column water vapor over land and clouds (in cm), smoke injection height (m above ground), AOD QA, AOD model at 1km, cosine of solar zenith angle, cosine of view zenith angle, relative azimuth angle, scattering angle, and glint angle at 5km. A low-resolution browse image is also included showing AOD of the blue band at 0.47 µm created using a composite of all available orbits. Each SDS layer within each MCD19A2 Hierarchical Data Format 4 (HDF4) file contains a third dimension that represents the number of orbit overpasses. This factor could affect the total number of bands for each SDS layer. Validation at stage 1 (https://landweb.modaps.eosdis.nasa.gov/cgi-bin/QA_WWW/newPage.cgi?fileName=maturity) has been achieved for the AOD SDS layers. Further details regarding MODIS land product validation for MCD19 data products are available from the MODIS Land Team Validation site (https://modis-land.gsfc.nasa.gov/ValStatus.php?ProductID=MOD19). Improvements/Changes from Previous Versions * The Version 6.1 Level-1B (L1B) products have been improved by undergoing various calibration changes that include: changes to the response-versus-scan angle (RVS) approach that affects reflectance bands for Aqua and Terra MODIS, corrections to adjust for the optical crosstalk in Terra MODIS infrared (IR) bands, and corrections to the Terra MODIS forward look-up table (LUT) update for the period 2012 - 2017. * A polarization correction has been applied to the L1B Reflective Solar Bands (RSB). * The MCD19 Version 6.1 products have added 250 m resolution bands. * The previous BRDF product (MCD19A3) was reported once every eight days and the new MCD19A3D is a daily product. * MCD19A3D introduces gap-filled NDVI and gap-filled 250 m NBAR. * Snow Fraction, Snow Fit, and Snow Grain size layers were moved from MCD19A1 to the MCD19A3D. * There are four additional Climate Modeling Grid (CMG) products: MCD19A1CMGL, MCD19A1GO, MCD19A2CMG, and MCD19A3CMG.

The new Collection 6.1 (C61) MODIS/Terra Aerosol 5 Min L2 Swath 3km (MOD04_3K) product is an improved version based on algorithm changes in Dark Target (DT) Aerosol retrieval over urban areas and uncertainty estimates for Deep Blue (DB) Aerosol retrievals. The MODIS level-2 atmospheric aerosol product provides retrieved ambient aerosol optical properties, quality assurance, and other parameters, globally over ocean and land. In Collection 5, and earlier collections, there was only one aerosol product (MOD04_L2) at 10km (at nadir) spatial resolution. Starting from C6, the Dark Target (DT) Aerosol algorithm team provided a new 3 km spatial resolution product (MOD04_3k) intended for the air quality community. The MOD04_3K product is based on the same algorithm and Look up Tables as the standard Dark Target aerosol product. Because of finer resolution, subtle differences are made in selecting pixels for retrieval and in determining QA. The only differences between the existing 10km algorithm and the new 3km algorithm are: 1) the size of the pixel-arrays defining each retrieval box ( 6x6 retrieval boxes of 36 pixels at 0.5km resolution for 3km algorithm as oppose to 20x20 retrieval boxes of 400 pixels at 0.5km resolution for 10km product); 2) the minimum percentage of "good" pixels required for a retrieval (a minimum of 5 pixels over ocean and 6 pixels over land instead of a minimum of 10 pixels over ocean or 12 pixels over land for 10km product retrieval); 3) the 10km algorithm attemptes a "poor quality" retrieval while 3km algorithm does not. Everything else is the same between two products. For more information on C6.1 changes and updates, visit the MODIS Atmosphere website at: https://modis-atmosphere.gsfc.nasa.gov/documentation/collection-61

The MODIS/Aqua Aerosol Optical Thickness Daily L3 Global 0.05-Deg CMA Near Real Time (NRT), short name MYD09CMA, is a daily level 3 global product. It is in linear latitude and longitude (Plate Carre) projection with a 0.05Deg spatial resolution. This product is derived from MYD09IDN, MYD09IDT and MYD09IDS for each orbit by compositing the data on the basis of minimum band 3 (459 - 479 nm band) values (after excluding pixels flagged for clouds and high solar zenith angles).

The Moderate Resolution Imaging Spectroradiometer (MODIS) Near Real Time (NRT) Combined Terra and Aqua Multi-Angle Implementation of Atmospheric Correction (MAIAC) Land Aerosol Optical Depth gridded Level 2 product (MCD19A2N) produced daily at 1 kilometer (km) pixel resolutions. The MCD19A2N product provides the atmospheric properties and view geometry used to calculate the MAIAC Land Surface Bidirectional Reflectance Factor (BRF) or surface reflectance, MCD19A1N product. The Version 6.1 Level-1B (L1B) products have been improved by undergoing various calibration changes that include: changes to the response-versus-scan angle (RVS) approach that affects reflectance bands for Aqua and Terra MODIS, corrections to adjust for the optical crosstalk in Terra MODIS infrared (IR) bands, and corrections to the Terra MODIS forward look-up table (LUT) update for the period 2012 - 2017. A polarization correction has been applied to the L1B Reflective Solar Bands (RSB).

The new Collection 6.1 (C61) MODIS/Aqua Aerosol 5 Min L2 Swath 3km (MYD04_3K) product is an improved version based on algorithm changes in Dark Target (DT) Aerosol retrieval over urban areas and uncertainty estimates for Deep Blue (DB) Aerosol retrievals. The MODIS level-2 atmospheric aerosol product provides retrieved ambient aerosol optical properties, quality assurance, and other parameters, globally over ocean and land. In Collection 5, and earlier collections, there was only one aerosol product (MYD04_L2) at 10km (at nadir) spatial resolution. Starting from C6, the Dark Target (DT) Aerosol algorithm team provided a new 3 km spatial resolution product (MYD04_3k) intended for the air quality community. The MYD04_3K product is based on the same algorithm and Look up Tables as the standard Dark Target aerosol product. Because of finer resolution, subtle differences are made in selecting pixels for retrieval and in determining QA. The only differences between the existing 10km algorithm and the new 3km algorithm are: 1) the size of the pixel-arrays defining each retrieval box ( 6x6 retrieval boxes of 36 pixels at 0.5km resolution for 3km algorithm as oppose to 20x20 retrieval boxes of 400 pixels at 0.5km resolution for 10km product); 2) the minimum percentage of "good" pixels required for a retrieval (a minimum of 5 pixels over ocean and 6 pixels over land instead of a minimum of 10 pixels over ocean or 12 pixels over land for 10km product retrieval); 3) the 10km algorithm attempts a "poor quality" retrieval while 3km algorithm does not. Everything else is the same between two products. For more information on C6.1 changes and updates, visit the MODIS Atmosphere website at: https://modis-atmosphere.gsfc.nasa.gov/documentation/collection-61

The MODIS/Terra Dark Target Aerosol 5-Min L2 Swath 10 km product, short-name XAERDT_L2_MODIS_Terra is provided at 10-km spatial resolution (at-nadir) and a 5-minute cadence that typically yields about 140 granules over the daylit hours of a 24-hour period. The Terra/MODIS L2 collection record spans from January 2019 through December 2022. The XAERDT_L2_MODIS_Terra product is a part of the Geostationary Earth Orbit (GEO)–Low-Earth Orbit (LEO) Dark Target Aerosol project under NASA’s Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, led by Robert Levy, uses a special version of the MODIS Dark Target (DT) aerosol retrieval algorithm to produce Aerosol Optical Depth (AOD) and other aerosol parameters derived independently from seven sensor/platform combinations, where 3 are in GEO and 4 are in LEO. The 3 GEO sensors include Advanced Baseline Imagers (ABI) on both GOES-16 (GOES-East) and GOES-17 (GOES-West), and Advanced Himawari Imager (AHI) on Himawari-8. The 4 LEO sensors include MODIS on both Terra and Aqua, and VIIRS on both Suomi-NPP and NOAA-20. Adding the LEO sensors reinforces a major goal of this project, which is to render a consistent science maturity level across DT aerosol products derived from both types and sources of orbital satellites. The XAERDT_L2_MODIS_Terra product, in netCDF4 format, contains 45 Science Data Set (SDS) layers that include 8 geolocation and 37 geophysical SDSs. For more information consult LAADS product description page at: https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/XAERDT_L2_MODIS_Terra Or, Dark Target aerosol team Page at: https://darktarget.gsfc.nasa.gov/

The MODIS Near Real Time (NRT) Combined Aqua and Terra Albedo, MCD43A3N is the daily L3 16-day composite global gridded tiled product that provides the black-sky albedo and the white-sky albedo at local solar noon for each of the 7 land bands, visible, near infra-red and the short wave bands. The albedo is retrieved for the current data day as identified in the product granule id using the BRDF/Albedo model parameters provided in the daily MCD43A1N product. The product also contains the mandatory QA dataset for each of the spectral albedo dataset in the file. The C61 NRT BRDF code has been modified to allow for an extra round of magnitude inversion, following a full inversion using the full set of inputs. This extra magnitude inversion will only use the set of 9 days that are overlapping between standard and NRT, with the highest weight being assigned to the last day. Additional information from MODIS Land Science Team website at: https://modis-land.gsfc.nasa.gov/brdf.html