降下ばいじん量と降水量の間の関係について

Abstract

Based on the data acquired from dust-fall measurement during the period April 1982-March 1983,we have considered the relation between the dust-fall (M, t/(km)^2・mo) and the rain-water caught simultaneously (V, lit/mo); although the data utilized are only part of those that have been collected in the last 10 years or more and subsequent measurement are in progress, we believe our study to be interesting enough to report now. The findings are : (1) A plot of M/V against V is of hyperbolic shape, whereas that of M/V against l/V gives a straight line the slope of which is approximately equal to the annual average of M. (2) If we take M as ordinate and V as abscissa, we obtain a nearly linear relation which might be expressed by an equation M=m+αV-βV^2,where m is a constant independent of rain, while α and β are constants relating to the collection efficiency of a rain-drop for a dust-particle. (3) Using the values of α and β determined by the methed of least squares, the efficiency as averaged over the dust-fall measurement period has been estimated to be of the order of magnitude (10)^<-2> or so under some such meteorological conditions as rain-fall intensity 0.1 to 1.0mm/hr and rain-drop diameter 0.5-1.0mm.