scholarly journals A Three‐Dimensional Array for the Study of Infrasound Propagation Through the Atmospheric Boundary Layer

2019 ◽  
Vol 124 (16) ◽  
pp. 9299-9313 ◽  
Author(s):  
Madelon M. E. Smink ◽  
Jelle D. Assink ◽  
Fred C. Bosveld ◽  
Pieter S. M. Smets ◽  
Läslo G. Evers
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Three Dimensional ◽  
Dimensional Array

scholarly journals A pressure-driven atmospheric boundary layer model satisfying Rossby and Reynolds number similarity

2021 ◽  
Vol 6 (3) ◽  
pp. 777-790
Author(s):  
Maarten Paul van der Laan ◽  
Mark Kelly ◽  
Mads Baungaard
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Atmospheric Boundary Layer ◽  
Wind Farm ◽  
Three Dimensional ◽  
Computation Time ◽  
Wind Farms ◽  
The Mean ◽  
The Impact ◽  
Pressure Driven

Abstract. Idealized models of the atmospheric boundary layer (ABL) can be used to leverage understanding of the interaction between the ABL and wind farms towards the improvement of wind farm flow modeling. We propose a pressure-driven one-dimensional ABL model without wind veer, which can be used as an inflow model for three-dimensional wind farm simulations to separately demonstrate the impact of wind veer and ABL depth. The model is derived from the horizontal momentum equations and follows both Rossby and Reynolds number similarity; use of such similarity reduces computation time and allows rational comparison between different conditions. The proposed ABL model compares well with solutions of the mean momentum equations that include wind veer if the forcing variable is employed as a free parameter.

Novel Physical Simulators for Non-Synoptic Wind Systems

2020 ◽  
Author(s):  
Horia Hangan ◽  
Maryam Refan ◽  
Partha P. Sarkar ◽  
Delong Zuo
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Three Dimensional ◽  
Wind Tunnels ◽  
Wind Effects ◽  
The Past ◽  
Synoptic Wind ◽  
Physical Simulations ◽  
Wind Events ◽  
New Generation

The study of wind effects on buildings and structures is primarily based on physical simulations of wind events. Synoptic, atmospheric boundary layer (ABL) winds have been simulated in boundary layer wind tunnels. Non-synoptic wind events such as tornadoes and downbursts are three-dimensional, dynamic, and non-stationary, and, as a result, a new generation of physical simulators have emerged in the past decades. Some of these simulators, their performances as well as their limitations, are reviewed in this chapter.

scholarly journals 3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

2016 ◽  
Vol 9 (4) ◽  
pp. 1701-1720 ◽  
Author(s):  
Florian Späth ◽  
Andreas Behrendt ◽  
Shravan Kumar Muppa ◽  
Simon Metzendorf ◽  
Andrea Riede ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Water Vapor ◽  
Atmospheric Boundary Layer ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Differential Absorption ◽  
High Definition ◽  
Differential Absorption Lidar

Abstract. High-resolution three-dimensional (3-D) water vapor data of the atmospheric boundary layer (ABL) are required to improve our understanding of land–atmosphere exchange processes. For this purpose, the scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) was developed as well as new analysis tools and visualization methods. The instrument determines 3-D fields of the atmospheric water vapor number density with a temporal resolution of a few seconds and a spatial resolution of up to a few tens of meters. We present three case studies from two field campaigns. In spring 2013, the UHOH DIAL was operated within the scope of the HD(CP)2 Observational Prototype Experiment (HOPE) in western Germany. HD(CP)2 stands for High Definition of Clouds and Precipitation for advancing Climate Prediction and is a German research initiative. Range–height indicator (RHI) scans of the UHOH DIAL show the water vapor heterogeneity within a range of a few kilometers up to an altitude of 2 km and its impact on the formation of clouds at the top of the ABL. The uncertainty of the measured data was assessed for the first time by extending a technique to scanning data, which was formerly applied to vertical time series. Typically, the accuracy of the DIAL measurements is between 0.5 and 0.8 g m−3 (or < 6 %) within the ABL even during daytime. This allows for performing a RHI scan from the surface to an elevation angle of 90° within 10 min. In summer 2014, the UHOH DIAL participated in the Surface Atmosphere Boundary Layer Exchange (SABLE) campaign in southwestern Germany. Conical volume scans were made which reveal multiple water vapor layers in three dimensions. Differences in their heights in different directions can be attributed to different surface elevation. With low-elevation scans in the surface layer, the humidity profiles and gradients can be related to different land cover such as maize, grassland, and forest as well as different surface layer stabilities.

Impact of Elevated Kevin-Helmholtz Billows on the Atmospheric Boundary Layer

2021 ◽  
Author(s):  
Qingfang Jiang
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Shear Layer ◽  
Exponential Growth ◽  
Three Dimensional ◽  
Large Eddy Simulations ◽  
Two Dimensional ◽  
Large Eddy ◽  
Saturation Stage ◽  
The Impact

AbstractThe impact of Kelvin-Helmholtz billows (KHBs) in an elevated shear layer (ESL) on the underlying atmospheric boundary layer (BL) is examined utilizing a group of large-eddy simulations. In these simulations, KHBs develop in the ESL and experience exponential growth, saturation, and exponential decay stages. In response, strong wavy motion occurs in the BL, inducing rotor circulations near the surface when the BL is stable. During the saturation stage, secondary instability develops in the ESL and the wavy BL almost simultaneously, followed by the breakdown of the quasi-two-dimensional KH billows and BL waves into three-dimensional turbulence. Consequently, during and after a KH event, the underlying BL becomes more turbulent with its depth increased and stratification weakened substantially, suggestive of significant lasting impact of elevated KH billows on the atmospheric BL. The eventual impact of KHBs on the BL is found to be sensitive to both the ESL and BL characteristics.

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