scholarly journals Eye-Safe Diode-Laser-Based Micropulse Differential Absorption Lidar (DIAL) for Water Vapor Profiling in the Lower Troposphere

2011 ◽  
Vol 28 (2) ◽  
pp. 131-147 ◽  
Author(s):  
Amin R. Nehrir ◽  
Kevin S. Repasky ◽  
John L. Carlsten
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Second Generation ◽  
Continuous Wave ◽  
Single Photon ◽  
Average Power ◽  
Lower Troposphere ◽  
Master Oscillator ◽  
Differential Absorption ◽  
Differential Absorption Lidar

Abstract A second-generation diode-laser-based master oscillator power amplifier (MOPA) configured micropulse differential absorption lidar (DIAL) instrument for profiling of lower-tropospheric water vapor is presented. The DIAL transmitter is based on a continuous wave (cw) external cavity diode laser (ECDL) master oscillator that is used to injection seed two cascaded tapered semiconductor optical power amplifiers, which deliver up to 2-μJ pulse energies over a 1-μs pulse duration at 830 nm with an average power of ∼40 mW at a pulse repetition frequency of 20 kHz. The DIAL receiver utilizes a commercial 28-cm-diameter Schmidt–Cassegrain telescope, a 250-pm narrowband optical filter, and a fiber-coupled single-photon-counting Avalanche photodiode (APD) detector, yielding a far-field full-angle field of view of 170 μrad. A detailed description of the second-generation Montana State University (MSU) DIAL instrument is presented. Water vapor number density profiles and time–height cross sections collected with the water vapor DIAL instrument are also presented and compared with collocated radiosonde measurements, demonstrating the instruments ability to measure night- and daytime water vapor profiles in the lower troposphere.

scholarly journals Water Vapor Profiling Using a Widely Tunable, Amplified Diode-Laser-Based Differential Absorption Lidar (DIAL)

2009 ◽  
Vol 26 (4) ◽  
pp. 733-745 ◽  
Author(s):  
Amin R. Nehrir ◽  
Kevin S. Repasky ◽  
John L. Carlsten ◽  
Michael D. Obland ◽  
Joseph A. Shaw
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Incident Angle ◽  
Scattered Light ◽  
Optical Filter ◽  
External Cavity ◽  
Lower Troposphere ◽  
Differential Absorption ◽  
Differential Absorption Lidar ◽  
Laser Transmitter

Abstract A differential absorption lidar (DIAL) instrument for automated profiling of water vapor in the lower troposphere has been designed, tested, and is in routine operation at Montana State University. The laser transmitter for the DIAL instrument uses a widely tunable external cavity diode laser (ECDL) to injection seed two cascaded semiconductor optical amplifiers (SOAs) to produce a laser transmitter that accesses the 824–841-nm spectral range. The DIAL receiver utilizes a 28-cm-diameter Schmidt–Cassegrain telescope; an avalanche photodiode (APD) detector; and a narrowband optical filter to collect, discriminate, and measure the scattered light. A technique of correcting for the wavelength-dependent incident angle upon the narrowband optical filter as a function of range has been developed to allow accurate water vapor profiles to be measured down to 225 m above the surface. Data comparisons using the DIAL instrument and collocated radiosonde measurements are presented demonstrating the capabilities of the DIAL instrument.

scholarly journals Field-deployable diode-laser-based differential absorption lidar (DIAL) for profiling water vapor

2015 ◽  
Vol 8 (3) ◽  
pp. 1073-1087 ◽  
Author(s):  
S. M. Spuler ◽  
K. S. Repasky ◽  
B. Morley ◽  
D. Moen ◽  
M. Hayman ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Temporal Resolution ◽  
Filter Design ◽  
Wide Field ◽  
Atmospheric Conditions ◽  
Differential Absorption ◽  
Differential Absorption Lidar ◽  
Atmospheric Sciences ◽  
Range Resolution

Abstract. A field-deployable water vapor profiling instrument that builds on the foundation of the preceding generations of diode-laser-based differential absorption lidar (DIAL) laboratory prototypes was constructed and tested. Significant advances are discussed, including a unique shared telescope design that allows expansion of the outgoing beam for eye-safe operation with optomechanical and thermal stability; multistage optical filtering enabling measurement during daytime bright-cloud conditions; rapid spectral switching between the online and offline wavelengths enabling measurements during changing atmospheric conditions; and enhanced performance at lower ranges by the introduction of a new filter design and the addition of a wide field-of-view channel. Performance modeling, testing, and intercomparisons are performed and discussed. In general, the instrument has a 150 m range resolution with a 10 min temporal resolution; 1 min temporal resolution in the lowest 2 km of the atmosphere is demonstrated. The instrument is shown capable of autonomous long-term field operation – 50 days with a > 95% uptime – under a broad set of atmospheric conditions and potentially forms the basis for a ground-based network of eye-safe autonomous instruments needed for the atmospheric sciences research and forecasting communities.

scholarly journals Advances in Diode-Laser-Based Water Vapor Differential Absorption Lidar

2016 ◽  
Vol 119 ◽  
pp. 02003 ◽  
Author(s):  
Scott Spuler ◽  
Kevin Repasky ◽  
Bruce Morley ◽  
Drew Moen ◽  
Tammy Weckwerth ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Differential Absorption ◽  
Differential Absorption Lidar

scholarly journals Field deployable diode-laser-based differential absorption lidar (DIAL) for profiling water vapor

2014 ◽  
Vol 7 (11) ◽  
pp. 11265-11302 ◽  
Author(s):  
S. M. Spuler ◽  
K. S. Repasky ◽  
B. Morley ◽  
D. Moen ◽  
M. Hayman ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Temporal Resolution ◽  
Filter Design ◽  
Wide Field ◽  
Atmospheric Conditions ◽  
Differential Absorption ◽  
Differential Absorption Lidar ◽  
Atmospheric Sciences ◽  
Range Resolution

Abstract. A field deployable water vapor profiling instrument that builds on the foundation of the preceding generations of diode-laser-based differential absorption lidar (DIAL) laboratory prototypes has been constructed and tested. Significant advances are discussed, including: a unique shared telescope design that allows expansion of the outgoing beam for eye-safe operation with opto-mechanical and thermal stability, multi-stage optical filtering enabling measurement during daytime bright-cloud conditions, rapid spectral switching between the online and offline wavelengths enabling measurements during changing atmospheric conditions, and enhanced performance at lower ranges by the introduction of a new filter design and the addition of a wide field-of-view channel. Performance modeling, testing and intercomparisons have been performed and are discussed. In general, the instrument has 150 m range resolution with 10 min temporal resolution – 1 min temporal resolution in the lowest 2 km of the atmosphere is demonstrated. The instrument was shown capable of autonomous long term field operation – 50 days with a >95% uptime – under a broad set of atmospheric conditions and potentially forms the basis for a ground-based network of eye-safe autonomous instruments needed for the atmospheric sciences research and forecasting communities.

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