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

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 – all key features to enable larger 'national-scale' networks needed to characterize atmospheric moisture variability, which influences important processes related to weather and climate.  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.  Thus, a network of these instruments shows promise to provide atmospheric profiling capabilities needed by both the climate and weather forecasting research communities.</p>

scholarly journals MicroPulse DIAL (MPD) – a diode-laser-based lidar architecture for quantitative atmospheric profiling

2021 ◽  
Vol 14 (6) ◽  
pp. 4593-4616
Author(s):  
Scott M. Spuler ◽  
Matthew Hayman ◽  
Robert A. Stillwell ◽  
Joshua Carnes ◽  
Todd Bernatsky ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diode Laser ◽  
Quantitative Methods ◽  
Weather Forecasting ◽  
Cost Effective ◽  
Lower Atmosphere ◽  
High Spectral Resolution ◽  
Background Suppression ◽  
National Scale ◽  
Sensing Technology

Abstract. Continuous water vapor and temperature profiles are critically needed for improved understanding of the lower atmosphere and potential advances in weather forecasting skill. Ground-based, national-scale profiling networks are part of a suite of instruments to provide such observations; however, the technological method must be cost-effective and quantitative. We have been developing an active remote sensing technology based on a diode-laser-based lidar technology to address this observational need. Narrowband, high-spectral-fidelity diode lasers enable accurate and calibration-free measurements requiring a minimal set of assumptions based on direct absorption (Beer–Lambert law) and a ratio of two signals. These well-proven quantitative methods are known as differential absorption lidar (DIAL) and high-spectral-resolution lidar (HSRL). This diode-laser-based architecture, characterized by less powerful laser transmitters than those historically used for atmospheric studies, can be made eye-safe and robust. Nevertheless, it also requires solar background suppression techniques such as narrow-field-of-view receivers with an ultra-narrow bandpass to observe individual photons backscattered from the atmosphere. We discuss this diode-laser-based lidar architecture's latest generation and analyze how it addresses a national-scale profiling network's need to provide continuous thermodynamic observations. The work presented focuses on general architecture changes that pertain to both the water vapor and the temperature profiling capabilities of the MicroPulse DIAL (MPD). However, the specific subcomponent testing and instrument validation presented are for the water vapor measurements only. A fiber-coupled seed laser transmitter optimization is performed and shown to meet all of the requirements for the DIAL technique. Further improvements – such as a fiber-coupled near-range receiver, the ability to perform quality control via automatic receiver scanning, advanced multi-channel scalar capabilities, and advanced processing techniques – are discussed. These new developments increase narrowband DIAL technology readiness and are shown to allow higher-quality water vapor measurements closer to the surface via preliminary intercomparisons within the MPD network itself and with radiosondes.

scholarly journals Why Scanning Instruments Are a Necessity for Constraining Temperature and Humidity Fields in the Lower Atmosphere

2014 ◽  
Vol 31 (11) ◽  
pp. 2462-2481 ◽  
Author(s):  
David Themens ◽  
Frédéric Fabry
Keyword(s):  
Water Vapor ◽  
Microwave Radiometer ◽  
Three Dimensional ◽  
Optimal Estimation ◽  
Lower Atmosphere ◽  
Temperature Fields ◽  
Vertical Profiling ◽  
Thermodynamic Variables ◽  
Free Environment ◽  
Measurement Strategies

AbstractThe ability of different ground-based measurement strategies for constraining thermodynamic variables in the troposphere, particularly at the mesoscale, is investigated. First, a preliminary assessment of the capability of pure-vertical sounders for constraining temperature and water vapor fields in clear-sky conditions to current accuracy requirements is presented. Using analyses over one month from the Rapid Refresh model as input to an optimal estimation technique, it is shown that the horizontal density of a network of nonexisting, ideal vertical profiling instruments must be greater than 30 km in order to achieve accuracies of 0.5 g kg−1 for water vapor and 0.5 K for temperature. Then, an assessment of a scanning microwave radiometer’s capability for retrieving water vapor and temperature fields in a cloud-free environment over two- and three-dimensional mesoscale domains is also presented. The information content of an elevation and azimuthal scanning microwave radiometer is assessed using the same optimal estimation framework. Even though, in any specific pointing direction, the scanning radiometer does not provide much information, it is capable of providing considerably more constraints on thermodynamic fields, particularly water vapor, than a near-perfect vertical sounder. These constraints on water vapor are largely located within 80 km of the radiometer and between 1000- and 7000-m altitude, while temperature constraints are limited to within 35 km of the instrument at altitudes between the ground and 1500 m. The findings suggest that measurements from scanning radiometers will be needed to properly constrain the temperature and especially moisture fields to accuracies needed for mesoscale forecasting.

scholarly journals Simulated Multispectral Temperature and Atmospheric Composition Retrievals for the JPL GEO-IR Sounder

2021 ◽  
Author(s):  
Vijay Natraj ◽  
Ming Luo ◽  
Jean-Francois Blavier ◽  
Vivienne H. Payne ◽  
Derek J. Posselt ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Thermal Emission ◽  
Weather Forecasting ◽  
Lower Troposphere ◽  
Atmospheric Temperature ◽  
Atmospheric Composition ◽  
Near Surface ◽  
Infrared Measurements ◽  
Infrared Spectral ◽  
Shortwave Infrared

Abstract. Satellite measurements enable quantification of atmospheric temperature, humidity, and trace gas vertical profiles. The majority of current instruments operate on polar orbiting satellites and either in the thermal/mid-wave or in the shortwave infrared spectral regions. We present a new multispectral instrument concept for improved measurements from geostationary orbit (GEO) with sensitivity to the boundary layer. The JPL GEO-IR sounder, which is an imaging Fourier Transform Spectrometer, uses a wide spectral range (1–15.4 μm), encompassing both reflected solar and thermal emission bands to improve sensitivity to the lower troposphere and boundary layer. We perform retrieval simulations for both clean and polluted scenarios that also encompass different temperature and humidity profiles. The results illustrate the benefits of combining shortwave and thermal infrared measurements. In particular, the former adds information in the boundary layer, while the latter helps to separate near-surface and mid-tropospheric variability. The performance of the JPL GEO-IR sounder is similar to or better than currently operational instruments. The proposed concept is expected to improve weather forecasting, severe storm tracking and forecasting, and also benefit local and global air quality and climate research.

scholarly journals A Micro-Pulse Differential Absorption Lidar Test Network

2020 ◽  
Vol 237 ◽  
pp. 05001
Author(s):  
Scott Spuler ◽  
Todd Bernatsky ◽  
Catharine Bunn ◽  
Joshua Carnes ◽  
Matthew Hayman ◽  
...  
Keyword(s):  
Low Cost ◽  
Lower Atmosphere ◽  
State University ◽  
Differential Absorption ◽  
National Scale ◽  
Differential Absorption Lidar ◽  
Atmospheric Research ◽  
Montana State University ◽  
Weather And Climate ◽  
High Vertical Resolution

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.

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

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.

scholarly journals Improving the Retrieval of Cloudy Atmospheric Profiles from Brightness Temperatures Observed with a Ground-Based Microwave Radiometer

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 648
Author(s):  
Qing Li ◽  
Ming Wei ◽  
Zhenhui Wang ◽  
Sulin Jiang ◽  
Yanli Chu
Keyword(s):  
Water Vapor ◽  
Density Profile ◽  
Lower Troposphere ◽  
Microwave Remote Sensing ◽  
Atmospheric Temperature ◽  
Cloud Base ◽  
Vapor Density ◽  
Brightness Temperatures ◽  
Temperature And Humidity ◽  
Cloud Thickness

Atmospheric temperature and humidity retrievals from ground-based microwave remote sensing are useful in a variety of meteorological and environmental applications. Though the influence of clouds is usually considered in current retrieval algorithms, the resulting temperature and humidity estimates are still biased high in overcast conditions compared to radiosonde observations. Therefore, there is a need to improve the quality of retrievals in cloudy conditions. This paper presents an approach to make brightness temperature (TB) correction for cloud influence before the data can be used in the inversion of vertical profiles of atmospheric temperature and humidity. A three-channel method is proposed to make cloud parameter estimation, i.e., of the total 22 channels of the ground-based radiometer, three are adopted to set up a relationship between cloud parameters and brightness temperatures, so that the observations from the three channels can be used to estimate cloud thickness and water content and complete the cloud correction for the rest of the channels used in the retrieval. Based on two years of data from the atmosphere in Beijing, a comparison of the retrievals with radiosonde observations (RAOB) shows: (1) the temperature retrievals from this study have a higher correlation with RAOB and are notably better than in the vendor-provided LV2. The bias of the temperature retrievals from this study is close to zero at all heights, and the RMSE is greatly reduced from >5 °C to <2 °C in the layer, from about 1.5 km up to 5 km. The temperature retrievals from this study have higher correlation with RAOB data compared to the vendor-provided LV2, especially at and above a 2 km height. (2) The bias of the water vapor density profile from this study is near to zero, while the LV2 has a positive bias as large as 4 g/m3. The RMSE of the water vapor density profile from this study is <2 g/m3, while the RMSE for LV2 is as large as 10 g/m3. That is, both the bias and RMSE from this study are evidently less than the LV2, with a greater improvement in the lower troposphere below 5 km. Correlation with RAOB is improved even more for the water vapor density. The correlation of the retrievals from this study increases to one within the boundary layer, but the correlation of LV2 with RAOB is only 0.8 at 0.5 km height, 0.7 at 1 km, and even less than 0.5 at 2 km. (3) A parameter named the Cloud Impact index, determined by cloud water concentration and cloud thickness, together with the cloud base height, has been defined to show that both BIAS and RMSE of “high-CI subsample” are larger than those of the “low-CI subsample”, indicating that high-CI cloud has a higher impact on the retrievals and the correction for cloud influence is more necessary.

scholarly journals Development and comparisons of wind retrieval algorithms for small unmanned aerial systems

2012 ◽  
Vol 2 (2) ◽  
pp. 953-979 ◽  
Author(s):  
T. A. Bonin ◽  
P. B. Chilson ◽  
B. S. Zielke ◽  
P. M. Klein ◽  
J. R. Leeman
Keyword(s):  
Low Cost ◽  
Lower Atmosphere ◽  
Horizontal Wind ◽  
Unmanned Aerial Systems ◽  
Sodar Data ◽  
Wind Retrieval ◽  
Retrieval Algorithms ◽  
Conventional Instrumentation ◽  
Thermodynamic Variables ◽  
Aerial Systems

Abstract. Recently, there has been an increase in use of Unmanned Aerial Systems (UASs) as platforms for conducting fundamental and applied research in the lower atmosphere due to their relatively low cost and ability to collect samples with high spatial and temporal resolution. Concurrent with this development comes the need for accurate instrumentation and measurement methods suitable for small meteorological UASs. Moreover, the instrumentation to be integrated into such platforms must be small and lightweight. Whereas thermodynamic variables can be easily measured using well aspirated sensors onboard, it is much more challenging to accurately measure the wind with a UAS. Several algorithms have been developed that incorporate GPS observations as a means of estimating the horizontal wind vector, with each algorithm exhibiting its own particular strengths and weaknesses. In the present study, the performance of three such GPS-based wind-retrieval algorithms has been investigated and compared with wind estimates from rawinsonde and sodar observations. Each of the algorithms considered agreed well with the wind measurements from sounding and sodar data. Through the integration of UAS-retrieved profiles of thermodynamic and kinematic parameters, one can investigate the static and dynamic stability of the atmosphere and relate them to the state of the boundary layer across a variety of times and locations, which might be difficult to access using conventional instrumentation.

scholarly journals MicroPulse DIAL (MPD) – a Diode-Laser-Based Lidar Architecture for Quantitative Atmospheric Profiling

2021 ◽  
Author(s):  
Scott M. Spuler ◽  
Matthew Hayman ◽  
Robert A. Stillwell ◽  
Joshua Carnes ◽  
Todd Bernatsky ◽  
...  
Keyword(s):  
Diode Laser ◽  
Quantitative Methods ◽  
Weather Forecasting ◽  
Cost Effective ◽  
Lower Atmosphere ◽  
High Spectral Resolution ◽  
Background Suppression ◽  
National Scale ◽  
Sensing Technology ◽  
Spectral Fidelity

Abstract. Continuous water vapor and temperature profiles are critically needed for improved understanding of the lower atmosphere and potential advances in weather forecasting skill. Ground-based, national-scale profiling networks are part of a suite of instruments to provide such observations; however, the technological method must be cost-effective and quantitative. We have been developing an active remote sensing technology based on a diode-laser-based lidar architecture to address this observational need. Narrowband, high spectral fidelity diode lasers enable accurate and calibration-free measurements requiring a minimal set of assumptions based on direct absorption (Beer-Lambert law) and a ratio of two signals. These well-proven quantitative methods are known as differential absorption lidar (DIAL) and the high spectral resolution lidar (HSRL). This diode-laser-based architecture, characterized by less powerful laser transmitters than those historically used for atmospheric studies, can be made eye-safe and robust. Nevertheless, it also requires solar background suppression techniques such as narrow field-of-view receivers with an ultra-narrow bandpass to observe individual photons backscattered from the atmosphere. We will discuss this diode-laser-based lidar architecture's latest generation and analyze how it addresses a national-scale profiling network's need to provide continuous thermodynamic observations.

scholarly journals Comparison and application of wind retrieval algorithms for small unmanned aerial systems

2013 ◽  
Vol 2 (2) ◽  
pp. 177-187 ◽  
Author(s):  
T. A. Bonin ◽  
P. B. Chilson ◽  
B. S. Zielke ◽  
P. M. Klein ◽  
J. R. Leeman
Keyword(s):  
Low Cost ◽  
Lower Atmosphere ◽  
Horizontal Wind ◽  
Unmanned Aerial Systems ◽  
Sodar Data ◽  
Wind Retrieval ◽  
Retrieval Algorithms ◽  
Conventional Instrumentation ◽  
Thermodynamic Variables ◽  
Aerial Systems

Abstract. Recently, there has been an increase in use of Unmanned Aerial Systems (UASs) as platforms for conducting fundamental and applied research in the lower atmosphere due to their relatively low cost and ability to collect samples with high spatial and temporal resolution. Concurrent with this development comes the need for accurate instrumentation and measurement methods suitable for small meteorological UASs. Moreover, the instrumentation to be integrated into such platforms must be small and lightweight. Whereas thermodynamic variables can be easily measured using well-aspirated sensors onboard, it is much more challenging to accurately measure the wind with a UAS. Several algorithms have been developed that incorporate GPS observations as a means of estimating the horizontal wind vector, with each algorithm exhibiting its own particular strengths and weaknesses. In the present study, the performance of three such GPS-based wind-retrieval algorithms has been investigated and compared with wind estimates from rawinsonde and sodar observations. Each of the algorithms considered agreed well with the wind measurements from sounding and sodar data. Through the integration of UAS-retrieved profiles of thermodynamic and kinematic parameters, one can investigate the static and dynamic stability of the atmosphere and relate them to the state of the boundary layer across a variety of times and locations, which might be difficult to access using conventional instrumentation.

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