Based on our numerical investigations, a method of remote determination of the outer scale L0 of atmospheric turbulence from the ratio of acoustic radiation powers scattered at angles q1 <= 30° and q2 > q1 from the range 30° <= q2 <= 70° has been proposed. The method is capable of measuring L0 in the range from several tens of centimeters to 20 m with satisfactory accuracy. Efficiency of this method is illustrated by a numerical experiment. Its accuracy is estimated, and limits of applicability are specified.