Abstract
From the observations of the long-wave solar radiation made by means of a silver disc pyrheliometer with and without a red filter R. G. 2, during the period from Dec. 1939 to Dec. 1940, have been Linke's turbidity factors for total solar radiation τ, for long-wave τ, and for shortwave radiations τ' computed.
The annual variation of the turbidity factors at Tokyo is shown in Fig. 2. We perceive some times lags between τ' and τ', i.e, maximum of τ' and τ' occurs in late spring and in early summer respectively.
On the other hand, the amount of precipitable water W was calculated from the result of simultaneous radio-sounding W varies, as a whole, nearly lineary with the water vapour at the earth's surface, but in some cases there are found considerble deviations. Comparing the turbidity for long wave solar radiations τ' and the precipitable water W, we can find that τ' increases as W increases, but this correlation depends on the blueness of the sky in some extent.
The turbidity τa due to the particles suspended in the atmosphere was also computed correcting for the influence of water vapour for τ' It was shown that this turbidity τa has a close connection with the type of the air masses in the neighbourhood of Japan.
