1. SAG UV Last meetings: Melbourne, Australia, Jul 2011 Next meeting: Hannover, May 2015 Susana Diaz (Chair)

2. Members  Susana Diaz (Chair)  Vitali Fioletov  Jay Herman  Serm Janjai  Craig Sinclair  Gunther Seckmeyer  Tetsuro Uekubo  Ann Webb (Former Chair)  Geir Brathen, Oksana Tarasova (WMO)

3. Data Quality Measurements Substantial improvement in the accuracy of measurements  Davos RCC became a World Calibration Center (WCC)  Calibration of European instruments with the traveling standard instrument of WCC (Qasume project, and within COST 726)

4. Data Archive UV data is submitted to  WOUDC in Toronto, Canada  European UV Data Base (EUVDB) (European)  NSF Polar UV network contain UV (Polar) Data exchange formats in data centers are focused rather on the needs of instrument and atmospheric experts.

5. Documents  A Practical Guide for Operating Spectral Instruments Measuring Spectral Solar Ultraviolet Irradiance. SOPs. Addendum GAW Report N o 125, 2014.  Rationalizing Nomenclature for UV Doses and Effects on Humans. Joint publication of CIE and WMO, CIE 209:2014 WMO/GAW Report No. 211, 2014.

6. Data Quality Satellites  Satellites UV reconstruction from satellite information.  For clear skies, Snow and Aerosols are a challenge.  For cloudy skies, it is worse because of clouds. Satellites good for climatology, seasonal, ocean coverage.

7. UV Effects on Humans  The focus is moving from negative effects (skin cancer and cataract) toward positive effects (Vitamin D and Immune system).

8. UVI Public site in EC check UVI anywhere http://exp-studies.tor.ec.gc.ca/cgi- bin/clf2/uv_index_calculator?lang=e&printerversion=false&printfullpag e=false&accessible=offhttp://exp-studies.tor.ec.gc.ca/cgi- bin/clf2/uv_index_calculator?lang=e&printerversion=false&printfullpag e=false&accessible=off ? Many Institutions provide UVI Nevertheless, the procedure to perform the forecast is not standardized, then, the indexes provided by different sources may not be comparable.

9. Future  In the past: UV increases consequence of ozone decreases  In the future: Effect of other factors, in addition to ozone (cloud cover and types, earth reflectivity, aerosols, etch) Also, due to ice melting, underwater UV at high-latitudes would increase, affecting aquatic ecosystems.

10. Future Future variations in UV, driven by climate change and stratospheric ozone, will be  Spectral,  Geographical  Seasonal The effects on human health and ecosystems will not vary evenly worldwide and changes will not affect all the effects equally. Then, there is a clear necessity for monitoring surface UV radiation and quantifying future changes.

11. UV Weighted Irradiance Geographic and Seasonal Change 2002- 2008 1980- 1986

12. Reduce Gaps Consider the possibility of applying existing methods to derive UV radiation from good quality broadband (pyranometer) GAW data. Reduce gaps Longer time series Higher spatial resolution:

13. Promote the use of UV data for human health and ecosystems studies.  So far, the data exchange formats in data centers (WOUDC, EUVDB, NSF) are focused rather on the needs of instrument and atmospheric experts. Medical and biological communities are far less interested in technical details of UV measurements. Data exchange in more friendly formats

14. Improve Data Quality  Evaluate the possibility of calibrating instruments in other continents using the travelling standard instrument of WCC, Davos This would represent an important progress in data quality, mainly in developing countries.  Encourage Regional Calibration Centers

15. UV Index Many sites provide UV Index forecasts  Extension of UVI Scale (WHO)  Determine which countries / organizations are making UVI forecasts, and the basis of the forecasts.  Encourage the application of techniques using sky camera at the site, satellite image and weather model, to forecast cloud, improving the reliability of the UVI forecasting.

16. Data Quality Satellite  The Semi-Analytical Cloud Retrieval Algorithm (SACURA). The background spectral albedo is properly specified and cloud parameters are derived from the satellite’s infrared sensors.  Geostationary satellite data, covering most parts of the world with 20-30 years of historical data, and algorithms for deriving UV from geostationary satellite data are available

17. Documents  SOPs for multifilter will be produce in the next period.  Document on spectral instruments will be updated to adding new achievements.

18. Main future goals of the UV component of GAW  Promote the continuity of existing networks  Reduce gaps expanding the observational base, mainly in the Tropics and the Southern Hemisphere and promoting the use of longer GAW broadband time series to derive UV  Encourage measurements of parameters that drive UV variation  Further improve the quality of UV data and homogeneization of the UVI forecast  Better integrate the ground-based networks with regards to data archiving and distribution of UV data  Promote the use of UV data for human health and ecosystems studies and for model and satellite validation