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Full catalog/MCD18A1
MCD18A1·v061·dataset

Sunlight energy hitting the surface (Terra+Aqua, 1 km)

MODIS/Terra+Aqua Surface Radiation Daily/3-Hour L3 Global 1km SIN Grid V061
land NASA LPCLOUD Level 3 HDF-EOS2
In plain English

What it measures. Estimates of how much solar energy reaches the land surface, covering the shortwave part of sunlight that the ground actually receives. It reports values every 3 hours across a global 1-kilometer grid.

How it's made. Built from MODIS instruments on NASA's Terra and Aqua satellites (plus geostationary satellite data), processed into a daily gridded product using a method that works out incoming sunlight from surface reflectance.

How & where you'd use it. Feeds land-surface and climate models that need to know how much sun is hitting the ground. Note: this Version 6.1 was retired in June 2024, with users pointed to the newer Version 6.2.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › REFLECTANCELAND SURFACE › SURFACE RADIATIVE PROPERTIES › ALBEDOLAND SURFACE › SURFACE RADIATIVE PROPERTIES › ANISOTROPYATMOSPHERE › ATMOSPHERIC RADIATION › SHORTWAVE RADIATION

Coverage & cadence

  • Time span2000-02-24 → 2024-06-01
  • Measured byTerra (MODIS) · Aqua (MODIS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS2
  • StatusDEPRECATED

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 MCD18A1 Version 6.1 dataset was decommissioned on June 1, 2024. Users are encouraged to use the [MCD18A1 Version 6.2 data product](https://doi.org/10.5067/MODIS/MCD18A1.062). The MCD18A1 Version 6.1 is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Downward Shortwave Radiation (DSR) gridded Level 3 product produced daily at 1 kilometer pixel resolution with estimates of DSR every 3 hours. DSR is incident solar radiation over land surfaces in the shortwave spectrum (300-4,000 nanometers) and is an important variable in land-surface models that address a variety of scientific and application issues. The MCD18 products are based on a prototyping algorithm that uses multi-temporal signatures of MODIS data to derive surface reflectance and then calculate incident DSR using the look-up table (LUT) approach. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination/viewing geometry. Global DSR products are generated from MODIS and geostationary satellite data. Additional details regarding the methodology used to create the data are available in the Algorithm Theoretical Basis Document (ATBD). Provided in the MOD18A1 product are layers for instantaneous DSR array for each individual MODIS overpass and 3-hour DSR array along with a View Zenith Angle 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=MODIS&sat=TerraAqua&as=61).

Get the data

mcd18a1_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MCD18A1",
    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.