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Full catalog/MCD19A3D
MCD19A3D·v061·dataset

Surface reflectance correction settings (Terra+Aqua, 1 km)

MODIS/Terra+Aqua BRDF Model Parameters Daily L3 Global 1km SIN Grid V061
land NASA LPCLOUD Level 3 active HDF-EOS2
In plain English

What it measures. For each 1-km square of land, this records the numbers that describe how the surface reflects sunlight from different angles, so the same patch can be compared fairly whether the sun is high or low. Where snow is present it also tracks snow grain size and how much of the square is snow-covered, and over snow-free land it includes a greenness index and corrected true-color reflectance.

How it's made. Built by combining views from the MODIS instruments on NASA's Terra and Aqua satellites, then processed into a daily gridded map using an atmospheric-correction method that filters out clouds and haze.

How & where you'd use it. It feeds work on vegetation monitoring, snow mapping and consistent surface-color comparisons over time; it is mainly a technical input that other, more finished products rely on rather than something most people read directly.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › REFLECTANCEBIOSPHERE › VEGETATION › VEGETATION INDEXCRYOSPHERE › GLACIERS/ICE SHEETS › FIRN › SNOW GRAIN SIZECLIMATE INDICATORS › CRYOSPHERIC INDICATORS › SNOW COVERBIOSPHERE › VEGETATION › VEGETATION INDEX › NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)

Coverage & cadence

  • Time span2000-02-24 → ongoing
  • Measured byTerra (MODIS) · Aqua (MODIS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS2
  • StatusACTIVE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The MCD19A3D Version 6.1 data product is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Bidirectional Reflectance Distribution Function (BRDF) Model Parameters gridded Level 3 product. Output daily at 1 kilometer (km) resolution, the Multi-angle Implementation of Atmospheric Correction (MAIAC) MCD19A3D product provides three coefficients (weights) of the RossThick/Li-Sparse (RTLS) BRDF model that can be used to describe the anisotropy of each pixel. The retrievals represent cloud-free and low aerosol conditions. When snow is detected, gap-filled snow grain size and sub-pixel snow fraction are computed. The gap-filling process retains the parameter in MAIAC’s memory for each grid cell until updated with the latest cloud-free observation. The number of days since the last update is provided in a separate layer. Over snow-free land, MAIAC also reports gap-filled Normalized Difference Vegetation Index (NDVI) at 1 km resolution and gap-filled Nadir BRDF-Adjusted Reflectance (NBAR) at 250 m resolution in the red and near-infrared (NIR) bands. The MCD19A3 BRDF Model Parameters product contains the following Science Dataset (SDS) layers: RTLS isotropic kernel parameter (Kiso) for bands 1-8, the RTLS volumetric kernel parameter (Kvol) for bands 1-8, RTLS geometric kernel parameter (Kgeo) for bands 1-8, three snow parameters, NDVI, NBAR, and three separate layers for the number of days since last update to current day. Known Issues * Known issues are described in Section 6 of the User Guide. * An artifact was discovered in the NDVI1km and NBAR_250m layers over the southern polar region. The affected region shows false retrieval of data during the summer months. The artifacts occurred over permanently snow-covered areas where no meaningful NDVI retrieval is expected. A software fix was implemented for forward processing in June 2023. Existing data products will not be reprocessed. Affected dates are listed on the [Land Data Operational Products Evaluation Quality Assessment note](https://landweb.modaps.eosdis.nasa.gov/displayissue?id=187). * 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).

Get the data

mcd19a3d_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MCD19A3D",
    version="061",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LPCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.