1988 Volume 21 Pages 21-28
This paper describes a practical method of determining Angstrom's turbidity parameters and the precipitable water by using spectroradiometric data of direct solar irradiance both on the earth and in outer space. Atmospheric water vapor measurements have been performed for 21 different days from May 1986 to January 1987 in Kisarazu. Obtained valus were compared with those computed from radiosonde measurements data at Tateno, and the both were in good agreement. Conclusions are as follows : (1) Turbidity parameters in the spectral region of 375-650 nm differ from those in the 710-1000 nm region. The differences widen with the increasing water vapor contents. (2) The precipitable water on a clear day can be obtained from a terrestrial water vapor density, provided it is limited to daytime of ten to fifteen o'clock. The average rate of conversion is 1.6 mm to 1x10-6g/立法センチメ-トル.
