EPIC UV Aerosol Products

A variety of aerosol and aerosol-related products are derived from EPIC's observations. EPIC extends the multi-decadal long UV Aerosol Index (UVAI) record started in 1979 with TOMS and currently available from OMI observations. The EPIC UVAI detects carbonaceous aerosols, desert dust particles, and volcanic ash over the oceans and the continents under both clear and partly cloudy conditions, as well as over extremely bright backgrounds such as snow/ice surfaces and cloud decks. In addition to the qualitative UVAI product, EPIC observations yield aerosol optical depth (AOD) in the UV-VIS range, and near-UV single scattering albedo for both absorbing and non-absorbing aerosol types under cloud-free conditions using a modified version of the OMI aerosol algorithm. Because of the sensor's coarse spatial resolution, sub-pixel cloud contamination affects both the frequency of retrievals and the quality of the retrieved aerosol parameters. Figure A1 shows retrievals of UVAI, aerosol optical depth, single scattering albedo and absorption optical depth associated with smoke and desert dust events in Africa.

Recently developed retrieval approaches are applied to EPIC observations to obtain the optical depth of aerosol layers above clouds, as well as the cloud optical depth unaffected by aerosol absorption effects. Additionally, radiance measurements in the oxygen A- and B-bands are used to simultaneously derive the optical depth and the height of elevated desert dust and smoke aerosol layers over the oceans.

The EPIC UV aerosol products are available at the Atmospheric Science Data Center (ASDC) at NASA Langley Research Center: https://asdc.larc.nasa.gov/project/DSCOVR/DSCOVR_EPIC_L2_AER_03

See also https://asdc.larc.nasa.gov/data/DSCOVR/EPIC/L2_AER_03/.

Aerosol Index

Figure A1. EPIC derived UV aerosol index (top left), 388 nm aerosol optical depth (top right), 388 nm single scattering albedo (bottom left) and aerosol absorption optical depth (bottom right) derived from observations on August 7, 2016, 10:25 UTC.

Stratospheric Smoke Plume

Animation of a Smoke Plume

The movie above shows Stratospheric Injection of a Massive Smoke Plume from the Canadian Boreal Fires seen by DSCOVR/EPIC in August 2017. Unprecedented amounts of tropospheric carbonaceous aerosols generated by wildfires in British Columbia (BC) in Aug. 2017 were injected into the stratosphere. This event was observed by EPIC onboard DSCOVR. EPIC’s characterization of the BC plume was carried in terms of the UV Aerosol Index (UVAI) as the plume travelled above tropospheric clouds and in completely clear skies. The unusually high UVAI values (in excess of 20) recorded by EPIC for this plume pointed to an elevated aerosol layer between 12 and 16 km as confirmed by CALIOP (black lines). The resulting stratospheric carbonaceous aerosol layer was quickly moved eastward across the Atlantic Ocean, reaching Europe and Asia in about five days.