Consistency of Total Column Ozone Measurements Between the Brewer
Consistency of total column ozone measurements between the Brewer and Dobson spectroradiometers of the LKO Arosa and PMOD/WRC Davos Julian Gröbner1, Herbert Schill1, Luca Egli1, and René Stübi2 1 Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, PMOD/WRC, Davos, Switzerland 2 MeteoSwiss, Payerne, Switzerland Introduction The world's longest continuous total column ozone time series was initiated in 1926 at the Lichtklimatisches Observatorium (LKO), at Arosa, in the Swiss Alps with Dobson D002 (Staehelin, et al., 2018). Currently, three Dobson (D051, D062, D101) and three Brewer (B040, B072, B156) spectroradiometers are operated continuously. Since 2010, the spectroradiometers have been successively relocated to the PMOD/WRC, located in the nearby valley of Davos (1590~m.a.s.l.), at 12 km horizontal distance from Arosa (1850~m.a.s.l.). The last two instruments, Brewer B040 and Dobson D062 have been transferred in February 2021, successfully completing the transfer of the measurements from LKO Arosa to PMOD/WRC, Davos. Figure 3. View inside the MeteoSwiss with the Figure 1. Yearly (red), 11-year (burgundy and Gaussian-filtered Figure 2. The MeteoSwiss Brewer and Dobson automated Dobson spectroradiometer triad. 11-year (light green) averages of homogenized total column spectroradiometers in operation at PMOD/WRC. ozone at Arosa. Below are the timelines for the different instruments in operation at LKO Arosa and PMOD/WRC Davos. The problem The total column ozone measurements between Dobson and Brewer spectroradiometers show a significant seasonal variation of 1.6%, which is correlated to the effective ozone temperature. The effective ozone temperature is on average 225.2 K at PMOD/WRC, with a seasonal variation of amplitude 5.7 K.
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