MODIS Collection 6 Dark Target

World Meteorological Organization
MODIS Collection 6 "Dark Target"

The “dark-target” (DT) algorithm retrieves aerosol properties over oceans and primarily vegetated (“dark”) land surfaces. The quantitative products include total aerosol optical depth (AOD) over both ocean and land, and a measure of size distribution known as fine mode weighting (FMW) over ocean. Starting with Collection 6 (C6), the DT family includes products at two spatial resolutions: 10 x 10 km resolution (at nadir) (MxD04_L2; MOD04 for Terra and MYD04 for Aqua), 3 x 3 km product for air quality applications (MxD04_3K). MxD04 includes also other variables (derived aerosol properties, .e.g. Angstrom Exponent, columnar Mass Concentrations; diagnostics, e.g. Quality assurance, cloud fraction). MxD04_L2 also contains an additional AOD product with a statistical “merging” of the DT and the “deep-blue” (DB) AOD.

Example result / latest result (if near-real time)


EOS Terra / EOS Aqua


MODIS (Moderate-resolution Imaging Spectroradiometer)

Contact details



AOD, Angstrom exponent, fine mode ratio (over ocean)

Aerosol algorithm

“Dark-target” (DT); separate algorithm over ocean and land

Cloud screening

MOD35 + internal tests

Aerosol model

Ocean: Theoretical (pairing of fine and coarse modes with choice);

Land: derived from AERONET climatology (prescribed pairing of fine and coarse models)

Retrieval assumptions

Aerosol models: Bimodal (fine + coarse); flexible over ocean, prescribed over land.

Surface optical properties: Ocean: rough ocean a function of wind speed, Land: parameterized relationship between wavelength bands

Retrieval limitations

No retrieval over bright surfaces which include: ice/snow, glint over ocean and arid/desert regions over land

Spatial, temporal coverage

2000 - present (Terra), 2002 - present (Aqua), Standard and NRT, 2 day global

Spatial, temporal resolution

10 km and 3 km / 2330 km swath / 16 day repeat cycle

Operations status

Standard: operational / reprocessing (complete time series)

NRT: operational, latency of ~90 minutes

Validation status

2000-present online access to validation results

Quality control

pixel-wise quality assurance and confidence flags

last algorithm version

collection 6 (began 2014)

last validation



Algorithm description Product format description
Version explanation Validation summary


Product data access
Image / quicklook data access