Aerosol optical depths at BTN station

Measurements performed at BTN (Icaro Camp) in the austral summers 1988 and 1993
with the UVISIR-2 sun-photometer built at the FISBAT-Institute (cfr. References
below). Aerosol optical depth was evaluated taking into account molecular
scattering and gaseous absorption as H2O, O3 and NO2 (cfr. references below).
Aerosol optical depths were evaluated at 8 channels centered in the 400 - 1050
nm wavelength range. Because each scanning has the physical meaning of an
instantaneous picture of the atmosphere (with the sun at elevation h), we use a
single average time for each scanning . The scanning time interval is about
1.5 minutes. The relative optical air mass is also given. Data was taken under
clear-sky conditions. Legal maximum value of optical depth depends on
turbidity daily conditions and wavelength, ranging from 0.03 and 0.15.All
values are given with 3 digit. Missing data are indicated with a 999.000
value.