ESA CALVAL Calibration Campaign Izaña 2013
During the month of November the final campaign of the European Space Agency (ESA) project CEOS CAL-VAL Intercalibration of Spectrophotometers and Lidars was held at the Izaña Observatory. This project started in 2009 with the objective to improve the quality of the ozone measurements of the european spectrophotometers and study some discrepancies found between ground based spectrophotometers Brewer and Dobson and the measurements of ESA satellites. The Brewer and Dobson are the reference instruments for ozone measurements, with more than 200 stations around the Globe.
The Brewer Spectrophotometer is a versatile instrument that not only can measure total column ozone (O3), but in addition can provide sulfur dioxide (SO2), spectral Ultraviolet (UV) radiation, Aerosol Optical Depth (AOD) within the UV range, as well as ozone vertical profiles. This campaign is focused on the calibration of the direct sun measurements of this instrument to derive aerosol measurements. The direct calibration is a key parameter to explain the differences between ground-based instruments and satellites which are important at high latitudes and in the tropics. For this purpose an automatic shading device was developed and manufactured by the SIELTEC company (Tenerife, the Canary Islands).
Two teams from the Finnish and the Danish Meteorological Institutes participate at the campaign with instruments from Sodankyla (Finland), Sonderstom (Greenland,) and Copenhagen (Denmark) stations. Five brewer spectrometers were installed at the observatory and used the facilities of the RBCC-E (Regional Brewer Calibration Center – Europe) to calibrate and characterize the instruments. This camping is complementary to the campaigns celebrated at high latitudes at the Sodankyla Arctic Observatory and allows the evaluation of the instruments in complete different environments.
The shadow dispositive tested on the top of the Brewer European Reference #157. The Brewer Spectrophotometer is a versatile instrument can measure total column ozone (O3), sulfur dioxide (SO2), spectral Ultraviolet (UV) radiation, Aerosol Optical Depth (AOD) within the UV range, as well as ozone vertical profiles.
Participants from Finland, Denmark and Spain during the setup of the instruments at Izaña Observatory calibration platform.
From right to left, Ana Parus (La Laguna University) , Virgilio Carreño (AEMET, RBCC-E), Nis Lepsen (Danish Meteorological Institute), Juha Karhu ,Tomi Karprimen and Pauli Hekinen (Finish Meteorological Institute) and Alberto Redondas (AEMET,RBCC-E).