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Description

The MCD18A1 Version 6.2 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

Improvements/Changes from Previous Versions

  • MODIS shortwave infrared bands are included in the retrieval algorithm, which significantly reduces estimation uncertainties in cloud- and snow-covered pixels.
  • Inclusion of a new multispectral algorithm has been implemented to replace the blue band retrieval algorithm.
  • An improved climatology of surface spectral and broadband albedo was produced and used in the retrieval algorithm.

Product Summary

Platforms
Aqua,
Terra
Instruments
MODIS
Spatial Extent
N: 90 S: -90 E: 180 W: -180
Spatial Resolution
1000 Meters x 1000 Meters
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2000-02-24 to Present
Temporal Resolution
3 Hour
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
MODIS Adaptive Processing System, Terrestrial Information Systems Laboratory, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/MODAPS)
Concept ID
c2486249220-lpcloud
Data State
ACTIVE
Processing Level
3
Published
Updated

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Wang, D. (2024). MODIS/Terra+Aqua Surface Radiation Daily/3-Hour L3 Global 1km SIN Grid V062 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/MODIS/MCD18A1.062 Date Accessed: 2025-07-30

Data Center Citation

Dongdong Wang. 2024. MODIS/Terra+Aqua Surface Radiation Daily/3-Hour L3 Global 1km SIN Grid V062. Sioux Falls, South Dakota, USA: NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/MODIS/MCD18A1.062.

Documents

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) The ATBD provides physical theory and mathematical procedures for the calculations used to produce the data products.
GENERAL DOCUMENTATION The File Specification provides a description of the product file including Scientific Data Sets and their attributes.
PRODUCT QUALITY ASSESSMENT The LDOPE Land Product Quality Assessment website provides known issues, maneuvers, and product quality of the land products.
SCIENCE DATA PRODUCT VALIDATION Validation at stage 1 has been achieved for the MODIS Surface Radiation products.
SCIENCE DATA PRODUCT VALIDATION Further details regarding MODIS land product validation for the MCD18 data products are available from the MODIS Land Team Validation site.

Learning Resources

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