Brewer Intercomparison at Izaña
Published: Friday, November 11, 2011
At this moment, an interesting Brewer campaign is ongoing at the Regional Brewer Calibration Center for Europe (RBCC-E), Iberonesia, on Tenerife. As part of the ESA Cal/Val programme, instruments from the RBCC-E triad (AEMET, Spain) and instruments from the FMI (Finland) are being compared under different circumstances. The intercomparison has several goals.
These goals are to get a better characterisation of the instrument; learning more about the differences between the older MKII and MKIV models and the MKIII Brewers that we currently build; and also the campaign should provide more knowledge on absolute instrument calibrations, which are done for the regional and world standards. The picture below shows the instruments as they are waiting for sunrise to start measuring.
Earlier this year, the instruments were set up at a measurement campaign in northern Finland to measure at a high latitude. The station now used at the RBCC-E is close to the tropics. Due to the circulation of Ozone in the upper atmosphere, the conditions are very different at these sites. The station on Tenerife has stable Ozone all year round, with only small daily variations. The station in northern Finland instead has a big daily and seasonal variation. For instance, in spring the amount of Ozone is almost twice the amount in fall. Comparing the Ozone data derived from several instruments under such different circumstances will hopefully provide new insights that will make the Brewer spectrophotometer and Ozone measurements in general more accurate!
Thanks to Tapani Koskela from FMI for the picture.
http://www.iberonesia.net/index.php/Izana_esa_cal_val