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ASTER L2 Surface Reflectance VNIR and Crosstalk Corrected SWIR V004

The Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Surface Reflectance VNIR and Crosstalk Corrected SWIR (AST_07XT) dataset contains measures of the fraction of incoming solar radiation reflected from the Earth’s surface to the ASTER instrument corrected for atmospheric effects and viewing geometry for both the Visible and Near Infrared (VNIR) and Shortwave Infrared (SWIR) sensors. Both the VNIR and SWIR data are atmospherically corrected and are generated using the bands of the corresponding ASTER [L1B](https://doi.org/10.5067/ASTER/AST_L1B.004) image. The AST_07XT product has a spatial resolution of 15 meters (m) for the VNIR bands and 30 m for the SWIR bands.Known Issues* Level 2 products that are on the international date line/anti-meridian have incorrect bounding coordinates for the UTM zone defined in the file metadata.* SWIR data acquired after April 2008 may exhibit anomalous saturation and striping. Users should consult the ASTER SWIR User Advisory for additional details.Improvements/Changes from Previous Versions* SWIR Crosstalk Correction: Applies a correction to reduce stray light effects in the SWIR bands, enhancing data quality by minimizing artifacts. Enhanced Atmospheric Correction: Version 4 uses Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) data as the primary source for atmospheric parameters (ozone, water vapor, pressure, and temperature), improving the precision of emissivity calculations. Fallback Mechanisms: When MERRA-2 data are unavailable, the product employs Global Data Assimilation System (GDAS) data as a backup, with climatology data serving as a final fallback to ensure continuous processing. Radiometric Calibration Update: Version 4 applies Radiometric Calibration Coefficient Version 5 (RCC V5) to improve the radiometric accuracy of the raw DNs, based on research by [Tsuchida and others (2020)](https://doi.org/10.3390/rs12030427), published in Remote Sensing.

HLS Landsat Operational Land Imager Surface Reflectance and TOA Brightness Daily Global 30m v1.5

The HLSL30 V1.5 data product was decommissioned on January 4, 2022. Users are encouraged to use the improved [HLSL30 V2](https://doi.org/10.5067/HLS/HLSL30.002) data product.The Harmonized Landsat Sentinel-2 (HLS) project provides consistent surface reflectance (SR) and top of atmosphere (TOA) brightness data from the Operational Land Imager (OLI) aboard the joint NASA/USGS Landsat 8 satellite and the Multi-Spectral Instrument (MSI) aboard Europe’s Copernicus Sentinel-2A and Sentinel-2B satellites. The combined measurement enables global observations of the land every 2–3 days at 30-meter (m) spatial resolution. The HLS project uses a set of algorithms to obtain seamless products from OLI and MSI that include atmospheric correction, cloud and cloud-shadow masking, spatial co-registration and common gridding, illumination and view angle normalization, and spectral bandpass adjustment. The HLSL30 product provides 30-m Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) and is derived from Landsat 8 OLI data products. The [HLSS30](https://doi.org/10.5067/HLS/HLSS30.015) and HLSL30 products are gridded to the same resolution and Military Grid Reference System ([MGRS](https://hls.gsfc.nasa.gov/products-description/tiling-system/)) tiling system and thus are “stackable” for time series analysis.The HLSL30 product is provided in Cloud Optimized GeoTIFF (COG) format, and each band is distributed as a separate file. There are 10 bands included in the HLSL30 product along with one quality assessment (QA) band and four angle bands. For a more detailed description of the individual bands provided in the HLSL30 product, please see the User Guide.Provisional HLS V1.5 data have not been validated for their science quality and should not be used in science research or applications.Known Issues* HLSL30.015 products are based on input Landsat 8 L1TP (precision terrain corrected) products, which require identification of ground control targets for precision geometric correction. Images where ground control is not available (e.g., very cloudy images) cannot be processed to L1TP and are not included in the HLSL30 dataset.* Interruptions in data service occurred during a restaging of backlogged data between June 1 and June 15, 2021 for both HLSS30 and HLSL30 version 1.5 data products. During this time period increased errors in the processing workflow resulted in a significant number of data ingestion failures and thus, significant gaps in data availability. Given the pending release of the version 2.0, science quality HLS products, these missing data will not be filled for version 1.5. Users of the provisional version 1.5 products should be aware of the significant data gap in this two week window. The version 2.0 products will incorporate these data back into the archive. If you have any feedback or questions on the data please contact [Customer Services](https://www.earthdata.nasa.gov/centers/lp-daac/contact) or join our HLS conversion on the [Earthdata Forum](https://forum.earthdata.nasa.gov/viewtopic.php?f=7&t=618&hilit=hls&sid=95750d868b6448e0f4360a1473def234).

VIIRS/NPP Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V002

The Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance (VNP09GA) Version 2 product provides an estimate of land surface reflectance from the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS sensor. Data are provided for three imagery bands (I1-I3) at nominal 500 meter resolution (~463 meter) and nine moderate resolution bands (M1-M5, M7, M8, M10, M11) at nominal 1 kilometer (~926 meter) resolution. The 500 meter and 1 kilometer datasets are derived through resampling the native 375 meter and 750 meter VIIRS resolutions, respectively, in the Level 2 input product. These bands are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm are top-of-atmosphere reflectance for the VIIRS visible bands, the VIIRS cloud mask and aerosol product, aerosol optical thickness and atmospheric data obtained from the NOAA National Centers for Environmental Prediction (NCEP) reanalysis system. Along with the twelve reflectance bands are reflectance band quality, sensor azimuth angle, solar azimuth angle, sensor zenith angle, solar zenith angle, and observations layers. The reflectance layers from the VNP09GA data product are used as input data for many of the VIIRS land products. Known Issues* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS) and in Section 4.0 of the User Guide.Improvements/Changes from Previous Versions* Improved calibration algorithm and coefficients for entire Suomi NPP mission.* Improved geolocation accuracy and applied updates to fix outliers around maneuver periods.* Corrected the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid- to high-latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VNP13 Vegetation Indices and VNP43 Bidirectional Reflectance Distribution Function (BRDF)/Albedo.* Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data. * Replaced the land/water mask input product with the eight-class land/water mask from the VNP03 geolocation product that better aligns with MODIS.* Added secondary day-night flag to improve retrieval of Climate Modeling Grid (CMG) values over daytime pixels.* More details can be found in this [VIIRS Land V2 Changes document](https://landweb.modaps.eosdis.nasa.gov/data/userguide/VIIRS_Land_C2_Changes_09152022.pdf).

VIIRS/JPSS1 Surface Reflectance Daily L3 Global 0.05 Deg CMG NRT

The VJ109CMG_NRT is a Near Real Time (NRT) daily surface reflectance Climate Modeling Grid Version 2 product which provides an estimate of land surface reflectance from the NOAA-20 (previously called JPSS1) Visible Infrared Imager Radiometer Suite (VIIRS) sensor. Data are provided for three imagery bands (I1-I3) and nine moderate resolution bands (M1-M5, M7, M8, M10, M11) at 0.05 degree (~5,600 meter) resolution. The data are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. This product uses a weighted average of the best quality observation and is formatted as a CMG for use in climate simulation models. This product includes the twelve reflectance bands, five moderate resolution brightness temperature bands (M12-M16) and information layers representing relative azimuth angle, sensor zenith angle, solar zenith angle, reflectance band quality, time of day, and number mapping.Surface reflectance is obtained by adjusting top-of-atmosphere reflectance to compensate for atmospheric effects. Corrections are made for the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm include top-of-atmosphere reflectance for the VIIRS visible bands (VJ102MOD, VJ102IMG), the VIIRS cloud mask and aerosol product, aerosol optical thickness, and atmospheric data obtained from a reanalysis (surface pressure, atmospheric precipitable water, and ozone concentration).All surface reflectance products are produced for daytime conditions only. The product is produced under all atmospheric conditions except for night and oceans. Pixels when not produced are replaced by fill values in the Level-2 and Level-2G products.For more information read Suomi-NPP VIIRS Surface Reflectance User's Guide at https://viirsland.gsfc.nasa.gov/PDF/VIIRS_Surf_Refl_UserGuide_v2.0.pdfor visit VIIRS Land website at https://viirsland.gsfc.nasa.gov/Products/NASA/ReflectanceESDR.html

HLS Sentinel-2 Multi-spectral Instrument Surface Reflectance Daily Global 30m v1.5

The HLSS30 V1.5 data product was decommissioned on January 4, 2022. Users are encouraged to use the improved [HLSS30 V2](https://doi.org/10.5067/HLS/HLSS30.002) data product.The Harmonized Landsat Sentinel-2 (HLS) project provides consistent surface reflectance data from the Operational Land Imager (OLI) aboard the joint NASA/USGS Landsat 8 satellite and the Multi-Spectral Instrument (MSI) aboard the European Union’s Copernicus Sentinel-2A and Sentinel-2B satellites. The combined measurement enables global observations of the land every 2-3 days at 30 meter (m) spatial resolution. The HLS project uses a set of algorithms to obtain seamless products from OLI and MSI that include atmospheric correction, cloud and cloud-shadow masking, spatial co-registration and common gridding, illumination and view angle normalization, and spectral bandpass adjustment. The HLSS30 product provides 30 m Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) and is derived from Sentinel-2A and Sentinel-2B MSI data products. The HLSS30 and [HLSL30](https://doi.org/10.5067/HLS/HLSL30.015) products are gridded to the same resolution and Military Grid Reference System ([MGRS](https://hls.gsfc.nasa.gov/products-description/tiling-system/)) tiling system and thus are “stackable” for time series analysis.The HLSS30 product is provided in Cloud Optimized GeoTIFF (COG) format, and each band is distributed as a separate COG. There are 13 bands included in the HLSS30 product along with four angle bands and a quality assessment (QA) band. For a more detailed description of the individual bands provided in the HLSS30 product, please see the User Guide.Provisional HLS V1.5 data have not been validated for their science quality and should not be used in science research or applications.Known Issues* Interruptions in data service occurred during a restaging of backlogged data between June 1 and June 15, 2021 for both HLSS30 and HLSL30 version 1.5 data products. During this time period increased errors in the processing workflow resulted in a significant number of data ingestion failures and thus, significant gaps in data availability. Given the pending release of the version 2.0, science quality HLS products, these missing data will not be filled for version 1.5. Users of the provisional version 1.5 products should be aware of the significant data gap in this two week window. The version 2.0 products will incorporate these data back into the archive. If you have any feedback or questions on the data please contact [Customer Services](https://www.earthdata.nasa.gov/centers/lp-daac/contact) or join our HLS conversion on the [Earthdata Forum](https://forum.earthdata.nasa.gov/viewtopic.php?f=7&t=618&hilit=hls&sid=95750d868b6448e0f4360a1473def234).

Pre-Delta-X: L2 AVIRIS-NG Surface Spectral Reflectance across MRD, LA, USA, 2015-2016

This Level 2 (L2) dataset provides surface spectral reflectance data acquired over the Atchafalaya and Terrebonne basins of the Mississippi River Delta (MRD) of coastal Louisiana, USA, in 2015-2016. The data include georectified images with Lambertian-equivalent surface reflectance and composite mosaics with adjustments for Bidirectional Reflectance Distribution Function (BRDF) effects. The imagery was acquired by the Airborne Visible/Infrared Imaging Spectrometer - Next Generation (AVIRIS-NG), as part of the Pre-Delta-X campaign.

BOREAS RSS-01 PARABOLA SSA Surface Reflectance and Transmittance Data

The BOREAS RSS-01 team collected surface reflectance and transmittance data from three forested sites in the SSA. This data set contains averaged reflectance factors and transmitted radiances measured by the PARABOLA instrument at selected sites in the BOREAS SSA at different view angles and at three wavelength bands throughout the day. PARABOLA measurements were made during each of the three BOREAS IFCs during the growing season of 1994 at three SSA tower flux sites as well as during the FFC-T. Additional measurements were made in early and mid-1996 during the FFC-W and during IFC-2.

MODIS/Terra+Aqua Surface Reflectance (Bands 8-12) from MAIAC, Daily L3 Global 0.05Deg CMG V061

The MCD19A1CMGO Version 6.1 data product is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Multi-Angle Implementation of Atmospheric Correction (MAIAC) Surface Reflectance Level 3 (Bands 8-12) product produced daily in a 0.05 degree (5,600 meters at the equator) Climate Modeling Grid (CMG). The MCD19A1CMGO product is corrected for atmospheric gases and aerosols using a new MAIAC algorithm that is based on a time series analysis and a combination of pixel- and image-based processing. The MODIS MAIAC products provide an estimate of the surface spectral reflectance, also referred to as Bidirectional Reflectance Factor (BRF), as it would be measured at ground-level in the absence of atmospheric scattering or absorption. The Surface Reflectance dataset includes BRF, BRF normalized to a fixed geometry of solar zenith angle at 45° and nadir view, and Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) normalized to the nadir view and local sun angle at 1:30 pm.The MCD19A1CMGO MAIAC Surface Reflectance product for ocean bands includes 19 Science Dataset (SDS) layers: BRF for bands 8-12, BRF normalized to a fixed geometry for bands 8-12, NBAR for bands 8-12, Quality Assessment (QA) bits, cosine of solar zenith angle, cosine of view zenith angle, and relative azimuth angle. A low-resolution browse is also included.Known Issues* Known issues are described in Section 6 of the User Guide.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=TerraAqua&as=61).

MODIS/Aqua Surface Reflectance Daily L2G Global 250m SIN Grid V006

The MYD09GQ Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the [MYD09GQ Version 6.1](https://doi.org/10.5067/MODIS/MYD09GQ.061) data product.The MYD09GQ Version 6 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) 250 meter (m) bands 1 and 2, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Along with the 250 m bands are the Quality Assurance (QA) layer and five observation layers. This product is intended to be used in conjunction with the quality and viewing geometry information of the 500 m product (MYD09GA). Known Issues* The Collection 6 MODIS Land Surface Reflectance product (MYD09) may [incorrectly flag retrievals as ‘High Aerosol’](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=174) over brighter surfaces and at higher view angles. This will impact the downstream MODIS BRDF/Albedo (MCD43) and Vegetation Index (MOD13 and MYD13) data products which use the aerosol quantity flag to screen out high aerosol values.* [Corrections](https://landweb.modaps.eosdis.nasa.gov/data/userguide/LSRHighAerosolFlagFinal.pdf) were implemented in Collection 6.1 reprocessing.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Aqua&as=6).Improvements/Changes from Previous Versions* Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables.* Refinements to the internal snow, cloud, and cloud shadow detection algorithms. Uses Bidirectional Reflectance Distribution Function (BRDF) database to better constrain the different threshold used.* Processes ocean bands to create a new Surface Reflectance Ocean product and provides Quality Assurance (QA) datasets for these bands.* Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.

MODIS/Terra+Aqua Surface Reflectance (Bands 1-7) from MAIAC, Daily L3 Global 0.05Deg CMG V061

The MCD19A1CMGL Version 6.1 data product is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Multi-Angle Implementation of Atmospheric Correction (MAIAC) Surface Reflectance Level 3 (Bands 1-7) product produced daily in a 0.05 degree (5,600 meters at the equator) Climate Modeling Grid (CMG). The MCD19A1CMGL product is corrected for atmospheric gases and aerosols using a new MAIAC algorithm that is based on a time series analysis and a combination of pixel- and image-based processing. The MODIS MAIAC products provide an estimate of the surface spectral reflectance, also referred to as Bidirectional Reflectance Factor (BRF), as it would be measured at ground-level in the absence of atmospheric scattering or absorption. The Surface Reflectance dataset includes BRF, BRF normalized to a fixed geometry of solar zenith angle at 45° and nadir view, and Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Reflectance (NBAR) normalized to the nadir view and local sun angle at 1:30 pm.The MCD19A1CMGL MAIAC Surface Reflectance product for land bands includes 25 Science Dataset (SDS) layers: BRF for bands 1-7, BRF normalized to a fixed geometry for bands 1-7, NBAR for bands 1-7, Quality Assessment (QA) bits, cosine of solar zenith angle, cosine of view zenith angle, and relative azimuth angle. A low-resolution browse is also included.Known Issues* Known issues are described in Section 6 of the User Guide.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=TerraAqua&as=61).

MODIS/Terra Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V006

The MOD09GA Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the [MOD09GA Version 6.1](https://doi.org/10.5067/MODIS/MOD09GA.061) data product.The MOD09GA Version 6 product provides an estimate of the surface spectral reflectance of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Bands 1 through 7, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Provided along with the 500 meter (m) surface reflectance, observation, and quality bands are a set of ten 1 kilometer (km) observation bands and geolocation flags. The reflectance layers from the MOD09GA are used as the source data for many of the MODIS land products. Known Issues* Striping due to a dead detector is noticeable for bands 5, 6, and 7 in scenes acquired February 24 through October 31, 2000. Corrections were implemented to reduce the striping in data acquired after November 1, 2000. Users should always check the band quality for dead detectors even though reflectance values may be in the valid range. * The Collection 6 MODIS Land Surface Reflectance product (MOD09) may [incorrectly flag retrievals as ‘High Aerosol’](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=86) over brighter surfaces and at higher view angles. This will impact the downstream MODIS BRDF/Albedo (MCD43) and Vegetation Index (MOD13 and MYD13) data products which use the aerosol quantity flag to screen out high aerosol values.* [Corrections](https://landweb.modaps.eosdis.nasa.gov/data/userguide/LSRHighAerosolFlagFinal.pdf) were implemented in Collection 6.1 reprocessing.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Terra&as=6).Improvements/Changes from Previous Versions* Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables.* Refinements to the internal snow, cloud, and cloud shadow detection algorithms. Uses Bidirectional Reflectance Distribution Function (BRDF) database to better constrain the different threshold used.* Processes ocean bands to create a new Surface Reflectance Ocean product and provides Quality Assurance (QA) datasets for these bands.* Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.

VIIRS/NPP Surface Reflectance 8-Day L3 Global 500m SIN Grid V002

The 8-day Visible Infrared Imaging Radiometer Suite (VIIRS) Surface Reflectance (VNP09H1) Version 2 composite product provides an estimate of land surface reflectance from the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS sensor for three imagery bands (I1, I2, I3) at nominal 500 meter resolution (~463 meter). The 500 meter dataset is derived through resampling the native 375 meter VIIRS resolution in the L2 input product. The data are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. Each pixel represents the best possible Level 2G observation during an 8-day period, which is selected on the basis of high observation coverage, low sensor angle, the absence of clouds or cloud shadow, and aerosol loading. This product includes three reflectance bands, a state quality assurance (QA) layer, and a reflectance band quality layer. Known Issues* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS) and in Section 4.0 of the User Guide.Improvements/Changes from Previous Versions* Improved calibration algorithm and coefficients for entire Suomi NPP mission.* Improved geolocation accuracy and applied updates to fix outliers around maneuver periods.* Corrected the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid- to high-latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VNP13 Vegetation Indices and VNP43 Bidirectional Reflectance Distribution Function (BRDF)/Albedo.* Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data. * Replaced the land/water mask input product with the eight-class land/water mask from the VNP03 geolocation product that better aligns with MODIS.* Added secondary day-night flag to improve retrieval of Climate Modeling Grid (CMG) values over daytime pixels.* More details can be found in this [VIIRS Land V2 Changes document](https://landweb.modaps.eosdis.nasa.gov/data/userguide/VIIRS_Land_C2_Changes_09152022.pdf).

MODIS/Aqua Surface Reflectance Daily L3 Global 0.05Deg CMG V061

The MYD09CMG Version 6.1 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Bands 1 through 7, resampled to 5600 meter (m) pixel resolution and corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. The MOD09CMG data product provides 25 layers including MODIS bands 1 through 7; Brightness Temperature data from thermal bands 20, 21, 31, and 32; along with Quality Assurance (QA) and observation bands. This product is based on a Climate Modeling Grid (CMG) for use in climate simulation models. Known Issues* A [striping anomaly in Band 5](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=939) of the MYD09CMG V61 product has been identified, caused by a dead detector in the AQUA Band 5, affecting data accuracy throughout the Aqua MODIS mission. * For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Aqua&as=61).Improvments/Changes from Previous Version* 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).

VIIRS/JPSS1 Atmospherically Corrected Surface Reflectance 6-Min L2 Swath IP 375m, 750m NRT

The VJ109_NRT is a Near Real Time (NRT) Visible Infrared Imager Radiometer Suite (VIIRS) 375 m, 750 m Atmospherically Corrected Surface Reflectance product. The VIIRS surface reflectance products are estimates of surface reflectance in each of the VIIRS reflective bands I1-I3, M1-M5, M7, M8, M10, and M11. The VNP09 Level-2 surface reflectance product contains approximately 6 minutes' worth of data. Surface reflectance for each moderate-resolution (750m) or imagery-resolution (375m) pixel is retrieved separately for the Level-2 products. Surface reflectance is obtained by adjusting top-of-atmosphere reflectance to compensate for atmospheric effects. Corrections are made for the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm include top-of-atmosphere reflectance for the VIIRS visible bands (VJ102MOD, VJ102IMG), the VIIRS cloud mask and aerosol product, aerosol optical thickness, and atmospheric data obtained from a reanalysis (surface pressure, atmospheric precipitable water, and ozone concentration).All surface reflectance products are produced for daytime conditions only. The product is produced under all atmospheric conditions except for night and oceans. Pixels when not produced are replaced by fill values in the Level-2 and Level-2G products.For more information read Suomi-NPP VIIRS Surface Reflectance User's Guide at https://viirsland.gsfc.nasa.gov/PDF/VIIRS_Surf_Refl_UserGuide_v2.0.pdfor visit VIIRS Land website at https://viirsland.gsfc.nasa.gov/index.html

VIIRS/JPSS1 Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V002

The Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance (VJ109GA) Version 2 product provides an estimate of land surface reflectance from the NOAA-20 VIIRS sensor. Data are provided for three imagery bands (I1-I3) at nominal 500 meter resolution (~463 meter) and nine moderate resolution bands (M1-M5, M7, M8, M10, M11) at nominal 1 kilometer (~926 meter) resolution. The 500 meter and 1 kilometer datasets are derived through resampling the native 375 meter and 750 meter VIIRS resolutions, respectively, in the Level 2 input product. These bands are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm are top-of-atmosphere reflectance for the VIIRS visible bands, the VIIRS cloud mask and aerosol product, aerosol optical thickness and atmospheric data obtained from the NOAA National Centers for Environmental Prediction (NCEP) reanalysis system. Along with the twelve reflectance bands are reflectance band quality, sensor azimuth angle, solar azimuth angle, sensor zenith angle, solar zenith angle, and observations layers. The reflectance layers from the VJ109GA data product are used as input data for many of the VIIRS land products. Known Issues* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS) and in Section 4.0 of the User Guide.Improvements/Changes from Previous Version* Improved calibration algorithm and coefficients for entire NOAA-20 mission.* Improved geolocation accuracy and applied updates to fix outliers around maneuver periods.* Corrected the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid- to high-latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VNP13 Vegetation Indices and VNP43 Bidirectional Reflectance Distribution Function (BRDF)/Albedo.* Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data. * Replaced the land/water mask input product with the eight-class land/water mask from the VNP03 geolocation product that better aligns with MODIS.* Added secondary day-night flag to improve retrieval of Climate Modeling Grid (CMG) values over daytime pixels.* More details can be found in this [VIIRS Land V2 Changes document](https://landweb.modaps.eosdis.nasa.gov/data/userguide/VIIRS_Land_C2_Changes_09152022.pdf).

MODIS/Aqua Surface Reflectance 8-Day L3 Global 250m SIN Grid V006

The MYD09Q1 Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the [MYD09Q1 Version 6.1](https://doi.org/10.5067/MODIS/MYD09Q1.061) data product.The MYD09Q1 Version 6 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Bands 1 and 2, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Provided along with the 250 meter (m) surface reflectance bands are two quality layers. For each pixel, a value is selected from all the acquisitions within the 8-day composite period. The criteria for the pixel choice include cloud and solar zenith. When several acquisitions meet the criteria the pixel with the minimum channel 3 (blue) value is used. Known Issues* The Collection 6 MODIS Land Surface Reflectance product (MYD09) may [incorrectly flag retrievals as ‘High Aerosol’](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=174) over brighter surfaces and at higher view angles. This will impact the downstream MODIS BRDF/Albedo (MCD43) and Vegetation Index (MOD13 and MYD13) data products which use the aerosol quantity flag to screen out high aerosol values.* [Corrections](https://landweb.modaps.eosdis.nasa.gov/data/userguide/LSRHighAerosolFlagFinal.pdf) were implemented in Collection 6.1 reprocessing.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Aqua&as=6).Improvements/Changes from Previous Versions* Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables.* Refinements to the internal snow, cloud, and cloud shadow detection algorithms. Uses Bidirectional Reflectance Distribution Function (BRDF) database to better constrain the different threshold used.* Processes ocean bands to create a new Surface Reflectance Ocean product and provides Quality Assurance (QA) datasets for these bands.* Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.

MODIS/Aqua Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V006

The MYD09GA Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the [MYD09GA Version 6.1](https://doi.org/10.5067/MODIS/MYD09GA.061) data product.The MYD09GA Version 6 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Bands 1 through 7, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Provided along with the 500 meter (m) surface reflectance, observation, and quality bands are a set of ten 1 km observation bands and geolocation flags. The reflectance layers from the MYD09GA are used as the source data for many of the MODIS land products. Known Issues* The Collection 6 MODIS Land Surface Reflectance product (MYD09) may [incorrectly flag retrievals as ‘High Aerosol’](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=174) over brighter surfaces and at higher view angles. This will impact the downstream MODIS BRDF/Albedo (MCD43) and Vegetation Index (MOD13 and MYD13) data products which use the aerosol quantity flag to screen out high aerosol values.* [Corrections](https://landweb.modaps.eosdis.nasa.gov/data/userguide/LSRHighAerosolFlagFinal.pdf) were implemented in Collection 6.1 reprocessing.* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Aqua&as=6).Improvements/Changes from Previous Versions* Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables.* Refinements to the internal snow, cloud, and cloud shadow detection algorithms. Uses Bidirectional Reflectance Distribution Function (BRDF) database to better constrain the different threshold used.* Processes ocean bands to create a new Surface Reflectance Ocean product and provide Quality Assurance (QA) datasets for these bands.* Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.

ABoVE: Lake Growing Season Green Surface Reflectance Trends, AK and Canada, 1984-2019

This dataset provides an annual time series of Landsat green surface reflectance and the derived annual trend during the growing season (June and July) for 472,890 lakes across the ABoVE Extended Study Domain from 1984 to 2019. The reflectance data are from Landsat-5, Landsat-7, and Landsat-8 sensors for the green band (center wavelength 560 nm). Over 270,000 Landsat scenes were evaluated and quality assured to be cloud-free and over water. Lakes were selected from HydroLAKES, a global database of lakes of at least 10 ha. Lake surface reflectance was extracted from a 3-by-3-pixel area centered on each lake centroid from the selected Landsat scenes determined from lake polygons. This dataset demonstrates changes in lake color over time in the arctic and boreal regions of North America. Color is relevant for understanding physical, ecological, and biogeochemical processes in some of the world’s highest concentrations of lakes where climate change may have significant impacts.

MODIS/Aqua Atmospherically Corrected Surface Reflectance 5-Min L2 Swath 250m, 500m, and 1km

The MODIS/Aqua Atmospherically Corrected Surface Reflectance 5-Min L2 Swath 250m, 500m, 1km (MYD09) 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), Bidirectional Reflectance Distribution Function (BRDF), thermal anomaly, snow/ice, and Fraction of Photosynthetically Active Radiation/Leaf Area Index (FPAR/LAI).

MODIS/Terra Surface Reflectance Daily L2G Global 250m SIN Grid V061

The MOD09GQ Version 6.1 product provides an estimate of the surface spectral reflectance of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) 250 meter (m) bands 1 and 2, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Along with the 250 m surface reflectance bands are the Quality Assurance (QA) layer and five observation layers. This product is intended to be used in conjunction with the quality and viewing geometry information of the 500 m product (MOD09GA). Known Issues* For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=MODIS&sat=Terra&as=61).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).