scholarly journals Remote probing of the optical strength of atmospheric turbulence and of wind velocity

1969 ◽  
Vol 57 (4) ◽  
pp. 415-420 ◽  
Author(s):  
D.L. Fried
Keyword(s):  
Atmospheric Turbulence ◽  
Wind Velocity ◽  
Remote Probing ◽  
Optical Strength

scholarly journals The Nature of Atmospheric Turbulence Effects on Imaging and Pseudo-Imaging Systems, and its Quantification

1979 ◽  
Vol 50 ◽  
pp. 4-1-4-44
Author(s):  
David L.
Keyword(s):  
Atmospheric Turbulence ◽  
Speckle Interferometry ◽  
Optical Propagation ◽  
Body Of Knowledge ◽  
Wavefront Distortion ◽  
Turbulence Effects ◽  
Atmospheric Turbulence Effects ◽  
Extensive Body ◽  
Proper Interpretation ◽  
Optical Strength

AbstractOver the last two decades, an extensive body of knowledge has been developed concerning the effects of atmospheric turbulence on optical propagation. Much of this is directly relevant to astronomical imaging, and with proper interpretation, to the type of pseudo-imagery that is of concern to us at this conference. This paper will provide an overview of this matter, hopefully with sufficient insight developed that the reader will be able to quickly estimate the nature and magnitude of the turbulence effects to be expected in a pseudo-imagery process. The paper starts with a review of turbulence effects on conventional imagery, reviewing the “nondimensional” nature of the turbulence statistics, presenting the local measure of the optical strength of turbulence,, and developing the resolution scale, r0. It presents a statistical view of the nature of the wavefront distortion geometry, indicating the dominance of the random wavefront tilt component. The MTF for conventional imagery and for speckle interferometry (Labeyrie) is presented with comments concerning their relationship. Following that, the foundation of the speckle imagery concept (Knox-Thompson) is presented. Results are then set forth for the allowable spectral bandwidth in speckle techniques, as well as results defining the allowable field-of-view size (isoplanatism) and the allowable exposure time for speckle techniques. Taken all together, these results provide a basis for estimating most of the significant effects of atmospheric turbulence in speckle interferometry and speckle imagery.

Boundary Layer Wind Characteristics over Urban Area

2014 ◽  
Vol 501-504 ◽  
pp. 2297-2300
Author(s):  
Lun Hai Zhi
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Urban Area ◽  
Atmospheric Turbulence ◽  
Wind Velocity ◽  
Three Dimensional ◽  
Tall Buildings ◽  
Gust Factor ◽  
Mean Wind Speed ◽  
Wind Characteristics

This paper presents statistical analysis results of wind speed and atmospheric turbulence data measured from a meteorological station in Beijing and is primarily intended to provide useful information on boundary layer wind characteristics for wind-resistant design of tall buildings and high-rise structures. Wind velocity data in longitudinal, lateral and vertical directions, which were recorded from an ultrasonic anemometer during windstorms, are analyzed and discussed. Atmospheric turbulence information such as turbulence intensity, gust factor, turbulence integral length scale and power spectral densities of the three-dimensional fluctuating wind velocity are presented and used to evaluate the adequacy of existing theoretical and empirical models. The objective of this study is to investigate the profiles of mean wind speed and atmospheric turbulence characteristics over a typical urban area.

scholarly journals Using Doppler lidar systems to detect atmospheric turbulence in Iceland

2019 ◽  
Author(s):  
Shu Yang ◽  
Guðrún Nína Petersen ◽  
Sibylle von Löwis ◽  
Jana Preißler ◽  
David Christian Finger
Keyword(s):  
Atmospheric Turbulence ◽  
Wind Velocity ◽  
Turbulence Intensity ◽  
Weather Conditions ◽  
Wind Fields ◽  
Air Traffic Controllers ◽  
Noise Filter ◽  
Filter Methods ◽  
Kolmogorov Theory ◽  
Lidar Observations

Abstract. The temporal and spatial scale of atmospheric turbulence is very dynamic, requiring an adequate method to detect and monitor turbulence with high resolution. Doppler Light Detection and Ranging (lidar) systems have been used widely to observe and monitor wind velocity and atmospheric turbulence profiles. Lidar systems can provide continuous information about wind fields using the Doppler effect from emitted light signals. In this study, we use a Leosphere Windcube 200S lidar system stationed in Reykjavik, Iceland, to evaluate turbulence intensity by estimating eddy dissipation rate (EDR). For this purpose, we retrieved radial wind velocity observations from velocity azimuth display (VAD) scans to compute EDR based on the Kolmogorov theory. We compared different noise filter methods, scan strategies and calculation approaches during different selected weather conditions to assess the accuracy of our EDR estimations. The results reveal that the lidar observations can detect and quantify atmospheric turbulence with high spatial and temporal resolution, our algorithm can retrieve EDR and indicate the turbulence intensity. These results suggest that lidar observation can be of high importance for potential end-user, e.g. air traffic controllers at the local airport. The work is an important step towards enhanced aviation safety in a subpolar climate characterized by severe wind turbulence.

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