Surface UV data record
Description
The surface ultraviolet (UV) radiation data record contains the following important quantities of solar radiation related to human health: solar noon UV index, daily maximum dose rates and daily maximum dose rates obtained by different biological weighting functions (action spectra) including erythemal, DNA damage, generalized plant damage, vitamin D synthesis, integrated UV-B and UV-A radiation. In addition, photolysis frequencies of ozone and nitrogen dioxide are included for air quality applications.
Type
Data record
Satellites and instruments
Multi-mission product. Total ozone column from GOME-2/Metop-A and/or GOME-2/Metop-B, cloud optical depth from AVHRR-3 onboard Metop-A, Metop-B, NOAA-18 and NOAA-19.
Algorithm version
2.2
Time period
01/06/2007 - 31/05/2017
Theoretical basis
The surface UV products are derived by radiative transfer modelling from the AC SAF total ozone column product and Advanced Very High Resolution Radiometer (AVHRR-3) reflectances, therefore combining data from two different instruments onboard the Metop satellites. Sampling of the diurnal cloud cycle is improved by using additional AVHRR-3 data from the NOAA satellites.
Processing
The data record was generated at FMI. The dose rates and photolysis frequencies are interpolated from a precomputed look-up table. Daily doses are obtained by integrating over the sunlit part of the day.
Units and spatial resolution
Daily doses are given in (kJ/m2), daily maximum dose rates in (mW/m2) and the photolysis frequencies in (s-1). The UV index is a unitless scale representing the risk level of skin damage due to UV exposure. All offline UV products are calculated in a 0.5° × 0.5° grid.
Validation
This data record is validated by FMI. The validation is based on detailed comparison of satellite data with ground-based measurements.
Archiving and dissemination
This product is archived at the FMI and available via data record access page.
File format and size
Files are in HDF5 format, each file containing global coverage for one day. The size of a single product file is approx. 18 MB.