Information about the OUV validation and online quality monitoring
The quality of the offline surface UV product is ensured by operational validation and online monitoring services provided by FMI. These services perform two different quality control mechanisms:
- Before OUV was declared ”operational” in May 2009, it was fully validated against quality-checked ground-based measurements. The results are provided in the latest validation report. Currently selected validation sites are listed below. More sites will be added to the list as they become available in order to obtain better global coverage when a new validation is performed in the future.
- The online quality monitoring of the OUV is performed to ensure that the product quality hasn't changed after the latest validation. When the daily OUV product is processed, two tracking values are recorded: global average of erythemal daily dose and global average of associated low quality flag. The first one produces graph with clear seasonal cycle where sudden changes would indicate problems with the satellite instruments or data processing. The second one is based on a ”low quality” flag (all quality flags are presented with the latest product), which is monitored to produce a graph where too high value (>0.5) indicates that too many pixels are either missing or their quality is poor otherwise. Both short-term (30 days) and long-term graphs of the tracking values are provided.
Ground-based measurement sites used for OUV validation:
| Site name | Country | Latitude | Longitude | Instrument | Data provider |
|---|---|---|---|---|---|
| Jokioinen | Finland | 60.81 N | 23.50 E | Brewer MkIII | FMI |
| Sodankylä | Finland | 67.37 N | 26.63 E | Brewer MkII | |
| Thessaloniki | Greece | 40.63 N | 22.96 E | Brewer MkIII | AUTH |
| Boulder | USA | 40.13 N | 105.24 W | Brewer MkIV | NEUBrew |
| Niwot Ridge | USA | 40.03 N | 105.53 W | Brewer MkIV | |
| Houston | USA | 29.72 N | 95.34 W | Brewer MkIV | |
| Bondville | USA | 40.05 N | 88.37 W | Brewer MkIV | |
| Raleigh | USA | 35.73 N | 78.68 W | Brewer MkIV | |
| Fort Peck | USA | 48.31 N | 105.10 W | Brewer MkIV | |
| Ushuaia | Argentina | 54.82 S | 68.32 W | SUV-100 | NSF |
| Summit | Greenland | 72.58 N | 38.45 W | SUV-150B | |
| San Diego | USA | 32.75 N | 117.18 W | SUV-100 | |
| Barrow | USA | 71.30 N | 156.78 W | SUV-100 |