1. NPI-NILU tasks (Ola Engelsen) •Further development of fast simulation tool for UV radiation (Fastrt) •Applications of fast simulation tool for quality assurance of UV spectra

2. Benefits •Complements on-site QA: obvious instrumental errors detected •Atmospheric indicators for UV data with little metadata available •Particularly relevant for data sources with automatic data recording

3. Principles •Fast simulations of representative scenarios •Comparison of measured UV spectra with simulations in UVA •Indicate most likely representative scenario (closest match) •Flag spectra which deviate far from representative scenarios

4. Generally speaking •- high radiation level: Snow, broken clouds or instrumental error •- low radiation level: Clouds, aerosols or instrumental error

5. Clouds and atmospheric anomalies •Cloud/cloudless flag •Optical thickness of clouds •High albedo •Broken clouds •Thick clouds •Clouds during scan period of spectra •Instrumental error

6. Limitations •Number of representative scenarios •Assumptions on radiative properties •Spectral response of instrument

7. Status •Main methodology in place •Accuracy and reliability testing remains •Modifications to meet speed requirements •Documentation must be updated