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Simultaneous wind and rainfall detection by power spectrum analysis using a VAD scanning coherent Doppler lidar
Optics Express
|November 6, 2019
Summary
This study introduces a coherent Doppler lidar (CDL) for simultaneous wind and precipitation detection. The CDL accurately measures wind profiles even during rain, reducing false wind speed detections.
Area of Science:
- Atmospheric science
- Remote sensing technology
- Meteorological instrumentation
Background:
- Doppler wind lidar (DWL) offers high-resolution wind detection but struggles with accuracy during precipitation due to raindrop interference.
- Precise wind profile measurements are crucial for weather forecasting and atmospheric studies, yet challenging in adverse weather conditions.
Purpose of the Study:
- To develop and validate a compact all-fiber coherent Doppler lidar (CDL) for simultaneous wind and precipitation detection.
- To improve the reliability of wind profile measurements under rainy conditions by distinguishing between aerosol and precipitation signals.
Main Methods:
- Utilized a 1.5 µm all-fiber coherent Doppler lidar (CDL) capable of precise spectrum measurement.
- Analyzed Doppler spectrum width to identify precipitation events, observing a characteristic two-peak spectrum.
- Applied a two-component Gaussian model for spectrum fitting to obtain distinct aerosol and rainfall velocities.
- Employed the velocity-azimuth display (VAD) scanning technique for simultaneous wind and rainfall speed retrieval.
Main Results:
- The CDL successfully detected both aerosol (wind) and rainfall signals under rainy conditions.
- Precipitation events were identified by spectrum width, with a distinct two-peak Doppler spectrum observed.
- Simultaneous retrieval of wind speed and rainfall speed was achieved using the VAD technique.
- Validation against weather balloons confirmed the lidar's performance.
Conclusions:
- The developed CDL system enables accurate simultaneous measurement of wind and precipitation.
- Distinguishing between aerosol and rainfall signals significantly reduces false wind speed detection during rain.
- This technology enhances the capability of Doppler lidar for meteorological applications in various weather conditions.
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