A Micro-Pulse Differential Absorption Lidar Test Network

The National Center for Atmospheric Research (NCAR) and Montana State University (MSU) have developed a test network of five micro-pulse Differential Absorption Lidar (DIAL) instruments to continuously measure high-vertical-resolution water vapor in the lower atmosphere. The instruments are accurate, low-cost, operate unattended, and eye-safe – all key features to enable larger ‘national-scale’ networks needed to characterize atmo-spheric moisture variability which influences important processes related to weather and climate.

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Micro-pulse, differential absorption lidar (dial) network for measuring the spatial and temporal distribution of water vapor in the lower atmosphere

EPJ Web of Conferences ◽

10.1051/epjconf/201817605012 ◽

2018 ◽

Vol 176 ◽

pp. 05012

Author(s):

Scott Spuler ◽

Kevin Repasky ◽

Matt Hayman ◽

Amin Nehrir

Keyword(s):

Water Vapor ◽

Low Cost ◽

Temporal Distribution ◽

Lower Atmosphere ◽

Atmospheric Moisture ◽

Differential Absorption ◽

Atmospheric Research ◽

Weather And Climate ◽

High Vertical Resolution ◽

Key Features

The National Center for Atmospheric Research (NCAR) and Montana State Univeristy (MSU) are developing a test network of five micro-pulse differential absorption lidars to continuously measure high-vertical-resolution water vapor in the lower atmosphere. The instruments are accurate, yet low-cost; operate unattended, and eye-safe – all key features to enable the larger network needed to characterize atmospheric moisture variability which influences important processes related to weather and climate.

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Probabilistic Design of Wind Turbine Blades with Treatment of Manufacturing Defects as Uncertainty Variables in a Framework

10.5194/wes-2017-14 ◽

2017 ◽

Cited By ~ 1

Author(s):

Trey W. Riddle ◽

Jared W. Nelson ◽

Douglas S. Cairns

Keyword(s):

Wind Turbine ◽

Probabilistic Models ◽

Low Cost ◽

Turbine Blades ◽

Design Parameters ◽

State University ◽

Wind Turbine Blades ◽

Manufacturing Defects ◽

Montana State University ◽

Blade Failure

Abstract. Given that wind turbine blades are such large structures, the use of low-cost composite manufacturing processes and materials has been necessary for the industry to be cost competitive. Since these manufacturing methods can lead to inclusion of unwanted defects, potentially reducing blade life, the Blade Reliability Collaborative tasked the Montana State University Composites Group with assessing the effects of these defects. Utilizing the results of characterization and mechanical testing studies, probabilistic models were developed to assess the reliability of a wind blade with known defects. As such, defects were found to best be assessed as design parameters in a parametric probabilistic analysis allowing for establishment of a consistent framework to validate categorization and analysis. Monte Carlo simulations were found to adequately describe the probability of failure of composite blades with included defects. By treating defects as random variables, the approaches utilized indicate the level of conservation used in blade design may be reduced when considering fatigue. In turn, safety factors may be reduced as some of the uncertainty surrounding blade failure is reduced when analysed with application specific data. Overall, the results indicate that characterization of defects and reduction of design uncertainty is possible for wind turbine blades.

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Vertical 2-μm Heterodyne Differential Absorption Lidar Measurements of Mean CO2 Mixing Ratio in the Troposphere

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2008jtecha1070.1 ◽

2008 ◽

Vol 25 (9) ◽

pp. 1477-1497 ◽

Cited By ~ 37

Author(s):

Fabien Gibert ◽

Pierre H. Flamant ◽

Juan Cuesta ◽

Didier Bruneau

Keyword(s):

Optical Depth ◽

Mesoscale Model ◽

Co2 Absorption ◽

Free Troposphere ◽

State University ◽

Mixing Ratio ◽

Differential Absorption ◽

Differential Absorption Lidar ◽

Backscatter Signal ◽

Synoptic Conditions

Abstract Vertical mean CO2 mixing ratio measurements are reported in the atmospheric boundary layer (ABL) and in the lower free troposphere (FT), using a 2-μm heterodyne differential absorption lidar (HDIAL). The mean CO2 mixing ratio in the ABL is determined using 1) aerosol backscatter signal and a mean derivative of the increasing optical depth as a function of altitude and 2) optical depth measurements from cloud target returns. For a 1-km vertical long path in the ABL, 2% measurement precision with a time resolution of 30 min is demonstrated for the retrieved mean CO2 absorption. Spectroscopic calculations are reported in details using new spectroscopic data in the 2-μm domain and the outputs of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). Then, using both aerosols in the ABL and midaltitude dense clouds in the free troposphere, preliminary HDIAL measurements of mean CO2 mixing ratio in the free troposphere are also presented. The 2-μm HDIAL vertical measurements are compared to ground-based and airborne in situ CO2 mixing ratio measurements and discussed with the atmospheric synoptic conditions.

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Testing and Validation of a Micro-Pulse, Differential Absorption Lidar (DIAL) for Measuring the Spatial and Temporal Distribution of Water Vapor in the Lower Atmosphere

Light, Energy and the Environment ◽

10.1364/ee.2016.ew3a.5 ◽

2016 ◽

Cited By ~ 1

Author(s):

Scott Spuler ◽

Tammy Weckwerth ◽

Kevin Repasky ◽

Matt Hayman ◽

Amin Nehrir

Keyword(s):

Water Vapor ◽

Temporal Distribution ◽

Lower Atmosphere ◽

Spatial And Temporal Distribution ◽

Differential Absorption ◽

Differential Absorption Lidar

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MicroPulse DIAL (MPD) ground-based network for Thermodynamic Profiling in the Lower Troposphere

10.5194/egusphere-egu2020-10310 ◽

2020 ◽

Author(s):

Scott Spuler ◽

Robert Stillwell ◽

Matt Hayman ◽

Tammy Weckwerth ◽

Kevin Repasky

Keyword(s):

Water Vapor ◽

Weather Forecasting ◽

Low Cost ◽

Lower Troposphere ◽

Atmospheric Temperature ◽

Lower Atmosphere ◽

High Spectral Resolution ◽

Montana State University ◽

Aerosol Scattering ◽

Thermodynamic Variables

<p>The National Center for Atmospheric Research and Montana State University have developed a 5-unit ground-based test network of MicroPulse Differential Absorption Lidar (MPD) instruments to continuously measure high-vertical-resolution water vapor profiles in the lower atmosphere. These diode-laser-based instruments are accurate, low-cost, operate unattended, do not require external calibration, and eye-safe &#8211; all key features to enable larger 'national-scale' networks needed to characterize atmospheric moisture variability, which influences important processes related to weather and climate.&#160; Enhancements to the water vapor MPD architecture have been recently developed that enable quantitative aerosol measurements and atmospheric temperature profiling by simultaneously measuring O2 absorption and aerosol backscatter ratio. This combination of measurements allows for the first DIAL measurements of atmospheric temperature with useful accuracy. The MPD has been demonstrated to provide continuous, range-resolved measurements of atmospheric thermodynamic variables, water vapor and temperature, and quantitative measurements of aerosol scattering from a high spectral resolution (HSRL) channel.&#160; Thus, a network of these instruments shows promise to provide atmospheric profiling capabilities needed by both the climate and weather forecasting research communities.</p>

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Towards low-cost water-vapour differential absorption lidar

10.1117/12.804740 ◽

2008 ◽

Cited By ~ 1

Author(s):

Murray Hamilton ◽

Roger Atkinson ◽

Alex Dinovitser ◽

Eva Peters ◽

Robert A. Vincent

Keyword(s):

Water Vapour ◽

Low Cost ◽

Differential Absorption ◽

Differential Absorption Lidar

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Effects of defects in composite wind turbine blades – Part 3: A framework for treating defects as uncertainty variables for blade analysis

Wind Energy Science ◽

10.5194/wes-3-107-2018 ◽

2018 ◽

Vol 3 (1) ◽

pp. 107-120 ◽

Cited By ~ 1

Author(s):

Trey W. Riddle ◽

Jared W. Nelson ◽

Douglas S. Cairns

Keyword(s):

Wind Turbine ◽

Probabilistic Models ◽

Low Cost ◽

Turbine Blades ◽

Design Parameters ◽

State University ◽

Wind Turbine Blades ◽

Montana State University ◽

Large Structures ◽

Blade Failure

Abstract. Given that wind turbine blades are large structures, the use of low-cost composite manufacturing processes and materials has been necessary for the industry to be cost competitive. Since these manufacturing methods can lead to the inclusion of unwanted defects, potentially reducing blade life, the Blade Reliability Collaborative tasked the Montana State University Composites Group with assessing the effects of these defects. Utilizing the results of characterization and mechanical testing studies, probabilistic models were developed to assess the reliability of a wind blade with known defects. As such, defects were found to be best assessed as design parameters in a parametric probabilistic analysis allowing for establishment of a consistent framework to validate categorization and analysis. Monte Carlo simulations were found to adequately describe the probability of failure of composite blades with included defects. By treating defects as random variables, the approaches utilized indicate the level of conservation used in blade design may be reduced when considering fatigue. In turn, safety factors may be reduced as some of the uncertainty surrounding blade failure is reduced when analyzed with application specific data. Overall, the results indicate that characterization of defects and reduction of design uncertainty is possible for wind turbine blades.

Download Full-text