CL System for UV calibration explained
During early October 2018, we quietly launched our new Continuous Learning (CL) auto-calibration system for UV. The system is designed to evaluate the raw UV sensor data from your SKY, and apply calibration corrections if needed. The data science and back-end techniques involved are fairly sophisticated; here’s a simplified explanation:
The UV CL system begins by considering a daily upper threshold UV index based on your precise location, the time of year, and the satellite observed global ozone concentration. Each day of your SKY’s data is then quality controlled and analyzed by smart algorithms to determine if the sky was clear around local solar noon, and therefore if your location would have observed close to the possible upper limit. When a sufficient amount of data has been analyzed, a calibration is then computed by comparing your observed UV to the threshold value on those days. The calibration is unique to each station, stored locally on your HUB, and applied automatically to each subsequent observation keeping your data in alignment forever.
Fortunately, UV sensors do not tend to drift much but we still run the UV CL system for each station once per day. This ensures that your station will remain in near perfect calibration on an ongoing basis (unlike any other weather station on the market!).
If your UV calibration still seems suspiciously high or low, please let us know directly and we’ll dig into your data.