Opening Statement
DSCOVR_EPIC_L2_AER_04 is the Deep Space Climate Observatory (DSCOVR) Enhanced Polychromatic Imaging Camera (EPIC) Level 2 UV Aerosol Version 4 data product. EPIC radiances measurements at 340 nm and 388 nm are used to derive near UV (ultraviolet) aerosol properties. The EPIC aerosol retrieval algorithm (EPICAERUV) uses a set of aerosol models to account for the presence of carbonaceous aerosols from biomass burning and wildfires (BIO), desert dust (DST), and urban-industrial (UIND) aerosols. These aerosol models are identical to those assumed in the OMI (Ozone Monitoring Instrument) algorithm (Torres et al., 2007; Jethva and Torres, 2011); however, adjusted to EPIC’s 340-nm wavelength The Oxygen-B band observations are used to derive the aerosol optical centroid height, which in turn is used to constrain the aerosol inversion at the UV wavelengths.
Mission/Campaign/Project Background
The Deep Space Climate Observatory (DSCOVR) and its aboard Earth Polychromatic Imaging Camera (EPIC) is a 10-channel spectroradiometer (317–780 nm) operating onboard the National Oceanic and Atmospheric Administration's (NOAA) DSCOVR spacecraft. The mission's primary objective is to provide a unique angular perspective of Earth from the Earth-Sun Lagrange-1 (L-1) point, enabling continuous full-disk imaging of the entire sunlit face of the Earth. EPIC's position at the L-1 point, combined with its 0.62-degree field of view and 2048×2048 pixel CCD detector coupled to a 30-cm aperture Cassegrain telescope, supports a broad range of Earth science applications. Due to DSCOVR's tilted (Lissajous) orbit about the L-1 point, the apparent angular size of Earth varies from 0.45 to 0.53 degrees within its 6-month orbital period, with a complete set of per-band images captured every 60 to 100 minutes depending on the season.
Data Products
Aerosol data products generated by the EPICAERUV algorithm are aerosol extinction optical depth (AOD) and single scattering albedo (SSA) at 340 nm and 388 nm for clear sky conditions. AOD of carbonaceous smoke and mineral dust absorbing aerosols above clouds is also reported (Jethva et al., 2018). Aerosol Optical Centroid Height (AOCH) is retrieved using the pair of observations made at 680 nm and 688 nm bands. In addition, the UV Aerosol Index (UVAI) is calculated from 340 and 388 nm radiances for all sky and all surface conditions. AOD is a dimensionless measure of the extinction of light by aerosols due to the combined effect of scattering and absorption. SSA represents the fraction of extinction solely due to aerosol scattering effects. The UVAI is a residual parameter that quantifies the difference in spectral dependence between measured and calculated near UV radiances, assuming a purely molecular atmosphere. Because most of the observed positive residuals are associated with absorbing aerosols, this parameter is commonly known as the UV Absorbing Aerosol Index. EPIC-derived aerosol parameters are reported at a 10 km (nadir) resolution. The UV Aerosol product covers entire sunlit side of the earth seen from L1 point and span the time range from June 15, 2015 to September 29, 2026.. This product data file is produced in HDF-EOS5 format.
Technical Details
| Parameter | Details |
|---|---|
| Spectral Coverage | 317–780 nm (10 narrow-band channels) |
| Detector | 2048×2048 pixel CCD |
| Telescope Aperture | 30-cm Cassegrain |
| Field of View | 0.62 degrees |
| Image Cadence | Every 60–100 minutes (season-dependent) |
| Processing Level | Level 1B |
| File Format | HDF5 |
| Spatial Coverage | Full sunlit disk of Earth |
| Platform Location | Earth-Sun L-1 Lagrange Point |
Access Information
For data access and more information, visit the DSCOVR EPIC Level 1B dataset landing page at Earthdata.
Access Methods
Users can access this data through:
Earthdata Search
User Support
For questions about this data release or assistance with data access, please contact the ASDC User Services team or visit the Earthdata Forum.