scholarly journals A Quasi-Simultaneous Dual Wavelength Water Vapor Differential Absorption Lidar Using PAS Cells.

1994 ◽  
Vol 22 (12) ◽  
pp. 1000-1006
Author(s):  
Chikao NAGASAWA ◽  
Makoto ABO ◽  
Kenji KIMIYAMA ◽  
Osamu UCHINO
Keyword(s):  
Water Vapor ◽  
Dual Wavelength ◽  
Differential Absorption ◽  
Differential Absorption Lidar

scholarly journals Differential absorption lidar measurements of water vapor by the High Altitude Lidar Observatory (HALO): Retrieval framework and validation

2021 ◽  
Author(s):  
Brian J. Carroll ◽  
Amin R. Nehrir ◽  
Susan Kooi ◽  
James Collins ◽  
Rory A. Barton-Grimley ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Altitude ◽  
Dynamic Range ◽  
Precipitable Water ◽  
Spatiotemporal Variability ◽  
High Spectral Resolution ◽  
Atmospheric Conditions ◽  
Differential Absorption ◽  
Differential Absorption Lidar ◽  
Wide Range

Abstract. Airborne differential absorption lidar (DIAL) offers a uniquely capable solution to the problem of measuring water vapor (WV) with high precision, accuracy, and resolution throughout the troposphere and lower stratosphere. The High Altitude Lidar Observatory (HALO) airborne WV DIAL was recently developed at NASA Langley Research Center and was first deployed in 2019. It uses four wavelengths at 935 nm to achieve sensitivity over a wide dynamic range, and simultaneously employs 1064 nm backscatter and 532 nm high spectral resolution lidar (HSRL) measurements for aerosol and cloud profiling. A key component of the WV retrieval framework is flexibly trading resolution for precision to achieve optimal data sets for scientific objectives across scales. A technique for retrieving WV in the lowest few hundred meters of the atmosphere using the strong surface return signal is also presented. The five maiden flights of the HALO WV DIAL spanned the tropics through midlatitudes with a wide range of atmospheric conditions, but opportunities for validation were sparse. Comparisons to dropsonde WV profiles were qualitatively in good agreement, though statistical analysis was impossible due to systematic error in the dropsonde measurements. Comparison of HALO to in situ WV measurements onboard the aircraft showed no substantial bias across three orders of magnitude, despite variance (R2 = 0.66) that may be largely attributed to spatiotemporal variability. Precipitable water vapor measurements from the spaceborne sounders AIRS and IASI compared very well to HALO with R2 > 0.96 over ocean and R2 = 0.86 over land.

scholarly journals Validation of a Water Vapor Micropulse Differential Absorption Lidar (DIAL)

2016 ◽  
Vol 33 (11) ◽  
pp. 2353-2372 ◽  
Author(s):  
Tammy M. Weckwerth ◽  
Kristy J. Weber ◽  
David D. Turner ◽  
Scott M. Spuler
Keyword(s):  
Water Vapor ◽  
Correlation Coefficient ◽  
Microwave Radiometer ◽  
Temporal Trends ◽  
Differential Absorption ◽  
Differential Absorption Lidar ◽  
Pearson’S Correlation ◽  
Pearson’S Correlation Coefficient ◽  
Pearson's Correlation ◽  
Pearson's Correlation Coefficient

AbstractA water vapor micropulse differential absorption lidar (DIAL) instrument was developed collaboratively by the National Center for Atmospheric Research (NCAR) and Montana State University (MSU). This innovative, eye-safe, low-power, diode-laser-based system has demonstrated the ability to obtain unattended continuous observations in both day and night. Data comparisons with well-established water vapor observing systems, including radiosondes, Atmospheric Emitted Radiance Interferometers (AERIs), microwave radiometer profilers (MWRPs), and ground-based global positioning system (GPS) receivers, show excellent agreement. The Pearson’s correlation coefficient for the DIAL and radiosondes is consistently greater than 0.6 from 300 m up to 4.5 km AGL at night and up to 3.5 km AGL during the day. The Pearson’s correlation coefficient for the DIAL and AERI is greater than 0.6 from 300 m up to 2.25 km at night and from 300 m up to 2.0 km during the day. Further comparison with the continuously operating GPS instrumentation illustrates consistent temporal trends when integrating the DIAL measurements up to 6 km AGL.

935 nm Differential Absorption Lidar System and Water Vapor Profiles in Convective Boundary Layer

2017 ◽  
Vol 37 (2) ◽  
pp. 0201003
Author(s):  
洪光烈 Hong Guanglie ◽  
李嘉唐 Li Jiatang ◽  
孔 伟 Kong Wei ◽  
葛 烨 Ge Ye ◽  
舒 嵘 Shu Rong
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Convective Boundary Layer ◽  
Differential Absorption ◽  
Lidar System ◽  
Differential Absorption Lidar ◽  
Convective Boundary

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.

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