Abstract

We describe a technique for measuring path-averaged rain parameters by analyzing the rainfall-induced scintillations of a laser beam. From the time-lagged covariance function of two vertically spaced line detectors, we determine the average rainfall rate and drop-size distribution along the optical path. This technique requires no prior assumption of the form of the drop-size distribution. Sample measurements on a 140-m path confirm that the path-averaged drop-size distribution of a steady rain follows a Marshall-Palmer distribution. The optically measured path-averaged rain rate also shows good agreement with conventional tipping-bucket rain-gauge data.

© 1977 Optical Society of America

Measurement of rain parameters by optical scintillation: computer simulation of the correlation method

Ting-i Wang and R. S. Lawrence
Appl. Opt. 16(12) 3176-3179 (1977)

Use of rainfall-induced optical scintillations to measure path-averaged rain parameters

Ting-i Wang and S. F. Clifford
J. Opt. Soc. Am. 65(8) 927-937 (1975)

Simplified optical path-averaged rain gauge

Ting-i Wang, K. B. Earnshaw, and R. S. Lawrence
Appl. Opt. 17(3) 384-390 (1978)

Laser rain gauge: near-field effect

Ting-i Wang, P. N. Kumar, and D. J. Fang
Appl. Opt. 22(24) 4008-4012 (1983)

Optical rain gauge using a divergent beam

Ting-i Wang, R. S. Lawrence, and M. K. Tsay
Appl. Opt. 19(21) 3617-3621 (1980)