A century of apparent atmospheric transmission over Davos, Switzerland

Lachat, D and Wehrli, C

Theoretical and Applied Climatology

2012

0177798X

539--547

110

Springer Science & Business Media

Issue Title: 125 Years of High-Mountain Research at Sonnblick Observatory (Austrian Alps) Pyrheliometer measurements have been carried out at the Physikalisches-Meteorologisches Observatorium Davos from 1909 to present which results in the longest stationary direct irradiance record worldwide. A variety of different instruments and measurement scales were homogenized and adjusted to the World Radiometric Reference. Following the pyrheliometric ratioing technique, a time-series of apparent atmospheric transmission was calculated and analyzed for possible trends in column transparency over Davos. In order to assess the trend found in the transmission record, the long-term annual cycle in apparent atmospheric transmission was used to deseasonalize the daily transmission data. The trends of early brightening, dimming and brightening were localized and found to be small but highly significant.[PUBLICATION ABSTRACT]

4

eng

Wien

Climate Change ; Meteorology ; Radiation ; Atmosphere