scholarly journals Remote sensing of multi-level wind fields with high-energy airborne scanning coherent Doppler lidar

1998 ◽  
Vol 2 (2) ◽  
pp. 40 ◽  
Author(s):  
Jeffry Rothermel ◽  
Lisa D. Olivier ◽  
Robert M. Banta ◽  
R. Michael Hardesty ◽  
James N. Howell ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Energy ◽  
Doppler Lidar ◽  
Wind Fields ◽  
Coherent Doppler Lidar ◽  
Multi Level

Estimating Spatial Velocity Statistics with Coherent Doppler Lidar

2002 ◽  
Vol 19 (3) ◽  
pp. 355-366 ◽  
Author(s):  
Rod Frehlich ◽  
Larry Cornman
Keyword(s):  
Radial Velocity ◽  
Spatial Scales ◽  
Energy Dissipation Rate ◽  
Doppler Lidar ◽  
Wind Fields ◽  
Velocity Statistics ◽  
Coherent Doppler Lidar ◽  
Spatial Velocity ◽  
Large Measurement ◽  
Turbulent Velocity Field

Abstract The spatial statistics of a simulated turbulent velocity field are estimated using radial velocity estimates from simulated coherent Doppler lidar data. The structure functions from the radial velocity estimates are processed to estimate the energy dissipation rate ε and the integral length scale Li, assuming a theoretical model for isotropic wind fields. The performance of the estimates are described by their bias, standard deviation, and percentiles. The estimates of ε2/3 are generally unbiased and robust. The distribution of the estimates of Li are highly skewed; however, the median of the distribution is generally unbiased. The effects of the spatial averaging by the atmospheric movement transverse to the lidar beam during the dwell time of each radial velocity estimate are determined, as well as the error scaling as a function of the dimensions of the total measurement region. Accurate estimates of Li require very large measurement domains in order to observe a large number of independent samples of the spatial scales that define Li.

Coherent Doppler lidar for measurements of wind fields

1989 ◽  
Vol 77 (3) ◽  
pp. 449-462 ◽  
Author(s):  
R.T. Menzies ◽  
R.M. Hardesty
Keyword(s):  
Doppler Lidar ◽  
Wind Fields ◽  
Coherent Doppler Lidar

scholarly journals Dynamic Scheduling Algorithm in Cyber Mimic Defense Architecture of Volunteer Computing

2021 ◽  
Vol 21 (3) ◽  
pp. 1-33
Author(s):  
Qianmu Li ◽  
Shunmei Meng ◽  
Xiaonan Sang ◽  
Hanrui Zhang ◽  
Shoujin Wang ◽  
...  
Keyword(s):  
Dynamic Scheduling ◽  
Scheduling Algorithm ◽  
Dynamic Change ◽  
High Energy ◽  
Transformation Rule ◽  
Volunteer Computing ◽  
Attack Behavior ◽  
Time Threshold ◽  
Security And Reliability ◽  
Multi Level

Volunteer computing uses computers volunteered by the general public to do distributed scientific computing. Volunteer computing is being used in high-energy physics, molecular biology, medicine, astrophysics, climate study, and other areas. These projects have attained unprecedented computing power. However, with the development of information technology, the traditional defense system cannot deal with the unknown security problems of volunteer computing . At the same time, Cyber Mimic Defense (CMD) can defend the unknown attack behavior through its three characteristics: dynamic, heterogeneous, and redundant. As an important part of the CMD, the dynamic scheduling algorithm realizes the dynamic change of the service centralized executor, which can enusre the security and reliability of CMD of volunteer computing . Aiming at the problems of passive scheduling and large scheduling granularity existing in the existing scheduling algorithms, this article first proposes a scheduling algorithm based on time threshold and task threshold and realizes the dynamic randomness of mimic defense from two different dimensions; finally, combining time threshold and random threshold, a dynamic scheduling algorithm based on multi-level queue is proposed. The experiment shows that the dynamic scheduling algorithm based on multi-level queue can take both security and reliability into account, has better dynamic heterogeneous redundancy characteristics, and can effectively prevent the transformation rule of heterogeneous executors from being mastered by attackers.

Characterization of turbulent wake of wind turbine by coherent Doppler lidar

2014 ◽  
Author(s):  
Songhua Wu ◽  
Jiaping Yin ◽  
Bingyi Liu ◽  
Jintao Liu ◽  
Rongzhong Li ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbulent Wake ◽  
Doppler Lidar ◽  
Coherent Doppler Lidar

scholarly journals Low-Level Wind Shear Identification along the Glide Path at BCIA by the Pulsed Coherent Doppler Lidar

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Hongwei Zhang ◽  
Xiaoying Liu ◽  
Qichao Wang ◽  
Jianjun Zhang ◽  
Zhiqiang He ◽  
...  
Keyword(s):  
Wind Shear ◽  
Vertical Direction ◽  
Small Scale ◽  
Observation Data ◽  
Doppler Lidar ◽  
Low Level ◽  
Glide Path ◽  
Coherent Doppler Lidar ◽  
Scanning Strategies ◽  
Meteorological Phenomenon

Low-level wind shear is usually to be a rapidly changing meteorological phenomenon that cannot be ignored in aviation security service by affecting the air speed of landing and take-off aircrafts. The lidar team in Ocean University of China (OUC) carried out the long term particular researches on the low-level wind shear identification and regional wind shear inducement search at Beijing Capital International Airport (BCIA) from 2015 to 2020 by operating several pulsed coherent Doppler lidar (PCDL) systems. On account of the improved glide path scanning strategy and virtual multiple wind anemometers based on the rang height indicator (RHI) modes, the small-scale meteorological phenomenon along the glide path and/or runway center line direction can be captured. In this paper, the device configuration, scanning strategies, and results of the observation data are proposed. The algorithms to identify the low-level wind shear based on the reconstructed headwind profiles data have been tested and proved based on the lidar data obtained from December 2018 to January 2019. High spatial resolution observation data at vertical direction are utilized to study the regional wind shear inducement at the 36L end of BCIA under strong northwest wind conditions.

Sign in / Sign up

Export Citation Format

Share Document