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R. K. Newsom, D. D. Turner, R. Lehtinen, C. Münkel, J. Kallio, and R. Roininen

Abstract

The performance of a novel water vapor broadband differential absorption lidar (BB-DIAL) is evaluated. This compact, eye-safe, diode-laser-based prototype was developed by Vaisala. It was designed to operate unattended in all weather conditions and to provide height-resolved measurements of water vapor mixing ratio in the lower troposphere. Evaluation of the Vaisala prototype was carried out at the U.S. Department of Energy’s Atmospheric Radiation Measurement site in north-central Oklahoma (i.e., the Southern Great Plains site) from 15 May to 12 June 2017. BB-DIAL measurements were compared with observations from radiosondes that were launched within 200 m of the BB-DIAL’s location. Radiosonde measurements are also compared with observations from a collocated Raman lidar and an Atmospheric Emitted Radiance Interferometer. During the evaluation period, the BB-DIAL operated continuously and did not experience any failures or malfunctions. The data availability was greater than 90% below 900 m but then decreased rapidly with height above this level to less than 10% above 1500 m AGL. From 106 radiosonde profiles, the overall mean difference (averaged temporally and vertically up to 1500 m) between the BB-DIAL and the radiosonde was −0.01 g kg−1, with a standard deviation of 0.65 g kg−1, and a linear correlation coefficient of 0.98. For comparison, the overall mean difference between the Raman lidar and the radiosonde was 0.07 g kg−1, with a standard deviation of 0.74 g kg−1, and a linear correlation coefficient of 0.97.

Open access
P. Klein, T. A. Bonin, J. F. Newman, D. D. Turner, P. B. Chilson, C. E. Wainwright, W. G. Blumberg, S. Mishra, M. Carney, E. P. Jacobsen, S. Wharton, and R. K. Newsom

Abstract

This paper presents an overview of the Lower Atmospheric Boundary Layer Experiment (LABLE), which included two measurement campaigns conducted at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains site in Oklahoma during 2012 and 2013. LABLE was conducted as a collaborative effort between the University of Oklahoma (OU), the National Severe Storms Laboratory, Lawrence Livermore National Laboratory (LLNL), and the ARM program. LABLE can be considered unique in that it was designed as a multiphase, low-cost, multiagency collaboration. Graduate students served as principal investigators and took the lead in designing and conducting experiments aimed at examining boundary layer processes.

The main objective of LABLE was to study turbulent phenomena in the lowest 2 km of the atmosphere over heterogeneous terrain using a variety of novel atmospheric profiling techniques. Several instruments from OU and LLNL were deployed to augment the suite of in situ and remote sensing instruments at the ARM site. The complementary nature of the deployed instruments with respect to resolution and height coverage provides a near-complete picture of the dynamic and thermodynamic structure of the atmospheric boundary layer. This paper provides an overview of the experiment including 1) instruments deployed, 2) sampling strategies, 3) parameters observed, and 4) student involvement. To illustrate these components, the presented results focus on one particular aspect of LABLE: namely, the study of the nocturnal boundary layer and the formation and structure of nocturnal low-level jets. During LABLE, low-level jets were frequently observed and they often interacted with mesoscale atmospheric disturbances such as frontal passages.

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Volker Wulfmeyer, David D. Turner, B. Baker, R. Banta, A. Behrendt, T. Bonin, W. A. Brewer, M. Buban, A. Choukulkar, E. Dumas, R. M. Hardesty, T. Heus, J. Ingwersen, D. Lange, T. R. Lee, S. Metzendorf, S. K. Muppa, T. Meyers, R. Newsom, M. Osman, S. Raasch, J. Santanello, C. Senff, F. Späth, T. Wagner, and T. Weckwerth

Abstract

Forecast errors with respect to wind, temperature, moisture, clouds, and precipitation largely correspond to the limited capability of current Earth system models to capture and simulate land–atmosphere feedback. To facilitate its realistic simulation in next-generation models, an improved process understanding of the related complex interactions is essential. To this end, accurate 3D observations of key variables in the land–atmosphere (L–A) system with high vertical and temporal resolution from the surface to the free troposphere are indispensable.

Recently, we developed a synergy of innovative ground-based, scanning active remote sensing systems for 2D to 3D measurements of wind, temperature, and water vapor from the surface to the lower troposphere that is able to provide comprehensive datasets for characterizing L–A feedback independently of any model input. Several new applications are introduced, such as the mapping of surface momentum, sensible heat, and latent heat fluxes in heterogeneous terrain; the testing of Monin–Obukhov similarity theory and turbulence parameterizations; the direct measurement of entrainment fluxes; and the development of new flux-gradient relationships. An experimental design taking advantage of the sensors’ synergy and advanced capabilities was realized for the first time during the Land Atmosphere Feedback Experiment (LAFE), conducted at the Atmospheric Radiation Measurement Program Southern Great Plains site in August 2017. The scientific goals and the strategy of achieving them with the LAFE dataset are introduced. We envision the initiation of innovative L–A feedback studies in different climate regions to improve weather forecast, climate, and Earth system models worldwide.

Open access