Apparent Transmission Time Series
The apparent transmission, is derived from broadband (0.2 to 4.0 µm) direct solar irradiance observations. Data are for clear-sky mornings between solar elevations of 11.3 and 30º (Ellis and Pueschel, 1971).
Ellis, H. T. and Pueschel, R. F. 1971. Solar radiation: absence of air pollution trends at Mauna Loa,Science, 172,845-846.