Data coverage
The Long-Term Data Record (LTDR) produces, validates, and distributes a global land surface climate data record (CDR) that uses both mature and well-tested algorithms in concert with the best-available polar-orbiting satellite data from past to the present. The CDR is critically important to studying global climate change. The LTDR project is unique in that it serves as a bridge that connects data derived from the NOAA Advanced Very High Resolution Radiometer (AVHRR), the EOS Moderate resolution Imaging Spectroradiometer (MODIS), the Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS), and Joint Polar Satellite System (JPSS) VIIRS missions. The LTDR draws from the following eight AVHRR missions: NOAA-7, NOAA-9, NOAA-11, NOAA-14, NOAA-16, NOAA-18, NOAA-19, and MetOp-B. Currently, the project generates a daily surface reflectance product as the fundamental climate data record (FCDR) and derives daily Normalized Differential Vegetation Index (NDVI) and Leaf-Area Index/fraction of absorbed Photosynthetically Active Radiation (LAI/fPAR) as two thematic CDRs (TCDR). LAI/fPAR was developed as an experimental product. The NOAA-07 AVHRR Atmospherically Corrected Normalized Difference Vegetation Index (NDVI) Daily L3 Global 0.05 Deg CMG, short-name N07AVH13C1 is generated from GIMMS Advanced Processing System (GAPS) BRDF-corrected Surface Reflectance product (N07AVH01C1). The N07AVH13C1 product is available in HDF4 file format. AERDTL2VIIRSNOAA20 The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) NASA standard Level-2 (L2) dark target (DT) aerosol product provides satellite-derived measurements of Aerosol Optical Thickness (AOT) and their properties over land and ocean, and spectral AOT and their size parameters over oceans every 6 minutes, globally. The VIIRS incarnation of the DT aerosol product is based on the same DT algorithm that was developed and used to derive products from the Terra and Aqua missions’ Moderate Imaging Spectroradiometer (MODIS) instruments. Two separate and distinct DT algorithms exist. One helps retrieve aerosol information over ocean (dark in visible and longer wavelengths), while the second aids retrievals over vegetated/dark-soiled land (dark in the visible wavelengths). This orbit-level product (Short-name: AERDTL2VIIRSNOAA20) has an at-nadir resolution of 6 km x 6 km, and progressively increases away from nadir given the sensor’s scanning geometry and Earth’s curvature. Viewed differently, this product’s resolution accommodates 8 x 8 native VIIRS moderate-resolution (M-band) pixels that nominally have ~750 m horizontal pixel size. Hence, the Level-2 Dark Target Aerosol Optical Thickness data product incorporates 64 (750 m) pixels over a 6-minute acquisition. Version 2.1 constitutes the latest collection of the NOAA-20 VIIRS L2 Dark Target Aerosol product and contains improvements over its previous collection (v2.0). For more information consult LAADS product description page at: https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/AERDTL2VIIRSNOAA20 Or, Dark Target aerosol team Page at: https://darktarget.gsfc.nasa.gov/ FSNRADL2VIIRSCRISNOAA20 The VIIRS-CrIS Data Fusion Level-2 Product is designed to facilitate improved continuity in derived cloud and moisture products realized with the High Resolution Infrared Radiation Sounder (HIRS) and the Moderate resolution Imaging Spectroradiometer (MODIS) and to continue other applications that require IR absorption spectral bands. Based on data fusion with VIIRS (Visible Infrared Imaging Radiometer Suite) and CrIS (Cross-track Infrared Sounder), infrared (IR) absorption band radiances for VIIRS are constructed at 750m spatial resolution (i.e., M-band resolution). These spectral bands are similar to the MODIS spectral bands. The fusion radiances, and look-up tables required to compute the related brightness temperatures, are stored in compressed NetCDF4 files of 6-minutes duration. This L2 NOAA-20 VIIRS+CrIS product release relates to Version-2.0 (v2.0) collection, which has undergone some improvements over its previous version. In the v2.0 Fusion product, scanlines are checked for quality instead of the entire input granule as was done in the previous version of this product. Such a process has helped salvage and use granules with continuous blocks of good data with good calibration. The v2.0 product also includes a couple of improvements to the VIIRS-CrIS collocation. The first relates to how VIIRS scan sync loss events are addressed while the other correctly characterizes VIIRS pixels that should have been identified as falling within a CrIS Field-of-View. A final improvement in the v2.0 product attempts to correct an artifact detected over warm, dry surfaces in the water vapor channels that are derived using the MODIS Band-27 and -28 response functions that apparently manifest signs of surface features that should not exist for these channels. Check the User Guide for further details on these improvements. The L2 VIIRS+CrIS Fusion product has a horizontal pixel size of 750 m, which is the native VIIRS moderate-resolution (M) band pixel-size. Consult the VIIRS+CrIS Fusion product User Guide (https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/viirs/VIIRSCrISFusionUserGuidev1.11.pdf) for additional information regarding this product’s algorithm, file format, global and data-field attributes, quality control flags, etc. AERDTL2VIIRSNOAA21 The NOAA-21 Visible Infrared Imaging Radiometer Suite (VIIRS) NASA standard Level-2 (L2) dark target (DT) aerosol product provides satellite-derived measurements of Aerosol Optical Thickness (AOT) and their properties over land and ocean, and spectral AOT and their size parameters over oceans every 6 minutes, globally. The VIIRS incarnation of the DT aerosol product is based on the same DT algorithm that was developed and used to derive products from the Terra and Aqua missions’ Moderate Imaging Spectroradiometer (MODIS) instruments. Two separate and distinct DT algorithms exist. One helps retrieve aerosol information over ocean (dark in visible and longer wavelengths), while the second aids retrievals over vegetated/dark-soiled land (dark in the visible wavelengths). This orbit-level product (Short-name: AERDTL2VIIRSNOAA21) has an at-nadir resolution of 6 km x 6 km, and progressively increases away from nadir given the sensor’s scanning geometry and Earth’s curvature. Viewed differently, this product’s resolution accommodates 8 x 8 native VIIRS moderate-resolution (M-band) pixels that nominally have ~750 m horizontal pixel size. Hence, the Level-2 Dark Target Aerosol Optical Thickness data product incorporates 64 (750 m) pixels over a 6-minute acquisition. Version 2.1 constitutes the first collection of the L2 Dark Target Aerosol product derived from the NOAA-21 VIIRS observations. For more information consult LAADS product description page at: https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/AERDTL2VIIRSNOAA21 Or, Dark Target aerosol team Page at: https://darktarget.gsfc.nasa.gov/ FSNRADL2VIIRSCRISSNPP The VIIRS-CrIS Data Fusion Level-2 Product is designed to facilitate improved continuity in derived cloud and moisture products realized with HIRS and MODIS and to continue other applications that require IR absorption spectral bands. Based on data fusion with VIIRS (Visible Infrared Imaging Radiometer Suite) and CrIS (Cross-track Infrared Sounder), infrared (IR) absorption band radiances for VIIRS are constructed at 750m spatial resolution (i.e., M-band resolution). These spectral bands are similar to the MODIS spectral bands. This L2 SNPP VIIRS+CrIS product release relates to Version-2.0 (v2.0) collection, which has undergone some improvements over its previous version. In the v2.0 Fusion product, scanlines are checked for quality instead of the entire input granule as was done in the previous version of this product. Such a process h
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