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Wind-bias correction method for narrowband sodium Doppler lidars using iodine absorption spectroscopy
Tao Yuan1, Jia Yue, Chiao-Yao She
1Department of Physics, Colorado State University, Fort Collins, Colorado 80523, USA. titus@lamar.colostate.edu
Applied Optics
|July 14, 2009
Summary
We developed a new method to measure laser frequency chirp in sodium lidar systems. This corrects wind bias, enabling accurate atmospheric temperature and wind measurements.
Area of Science:
- Atmospheric Science
- Laser Spectroscopy
- Remote Sensing
Background:
- Laser pulse amplification in lidar systems can introduce frequency chirp.
- This chirp leads to systematic errors in radial wind measurements.
- Accurate wind profiling in the mesopause region requires chirp correction.
Purpose of the Study:
- To present a novel technique for measuring laser frequency chirp in a sodium lidar system.
- To correct for the radial wind bias caused by this chirp.
- To enable simultaneous measurements of temperature and horizontal wind in the mesopause.
Main Methods:
- Utilized an iodine absorption line near the lidar's operating wavelength (589.16 nm).
- Implemented real-time monitoring and measurement of the frequency chirp.
- Validated the technique through laboratory characterization and field testing.
Main Results:
- Successfully measured the frequency chirp introduced during laser pulse amplification.
- Demonstrated the effectiveness of the iodine cell method for chirp correction.
- Enabled accurate, simultaneous measurements of temperature and horizontal wind.
Conclusions:
- The developed technique effectively measures and corrects for frequency chirp in sodium lidar.
- This method is crucial for obtaining unbiased wind measurements from the mesopause region.
- Facilitates improved atmospheric studies of the upper mesosphere.
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