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Measurement of rain parameters by optical scintillation
Applied Optics
|February 20, 2010
Summary
This study introduces a novel laser beam technique to measure rainfall rate and drop size distribution. The method accurately determines path-averaged rain parameters without assuming drop-size distribution forms.
Area of Science:
- Atmospheric Science
- Optical Remote Sensing
Background:
- Accurate measurement of rainfall parameters is crucial for hydrology and meteorology.
- Existing methods like tipping-bucket rain gauges provide point measurements, lacking path-averaged data.
Purpose of the Study:
- To develop and validate a new technique for measuring path-averaged rainfall rate and drop-size distribution.
- To assess the technique's performance against conventional methods.
Main Methods:
- Utilizing rainfall-induced scintillations of a laser beam.
- Analyzing the time-lagged covariance function of two vertically spaced line detectors.
- Determining path-averaged rain parameters without prior assumptions on drop-size distribution.
Main Results:
- The technique successfully determined path-averaged rainfall rate and drop-size distribution.
- Measurements on a 140-m path showed steady rain drop-size distribution aligns with the Marshall-Palmer distribution.
- Optically measured path-averaged rain rates closely matched tipping-bucket rain gauge data.
Conclusions:
- The laser scintillation technique offers a viable method for path-averaged rainfall measurement.
- This approach provides valuable data for understanding rainfall characteristics over extended paths.
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