| Summary: | Lidar systems have been used widely to measure wind profiles and atmospheric aerosols. The scanning Doppler lidars operated by the Icelandic Meteorological Office can provide continuous measurements of the wind velocity and direction based on the Doppler effect, from the emitted signal, as well as the backscatter coefficient and depolarization ratio for retrieving aerosol properties. In this project, we investigate the use of Doppler lidars in Iceland, especially for enhancing aviation safety. The project was divided into three main tasks have been conducted: 1) atmospheric turbulence measurements; 2) airborne aerosol detection; 3) real-time lidar signal classification with machine learning algorithms. In the first task, an algorithm was developed based on the Kolmogorov theory to retrieve eddy dissipation rate, as an indicator of turbulence intensity, from lidar wind measurements. The method was tested on two cases from 2017. In the second task, the Doppler lidar was used in combination with ceilometers, a sun-photometer and other instruments, to detect aerosols, including dust and volcanic ash in Iceland. In the third task, both supervised and unsupervised machine learning algorithms were developed to identify the noise signal and classify the lidar measurements, with the aim of providing real-time lidar signal classification for potential end-users. The results indicate that the Doppler lidar can significantly improve aviation safety and complement meteorological measurements by detecting atmospheric turbulence or volcanic ash clouds in Iceland. Vind- og agnasjár (e. lidar) hafa verið notaðar víða til að mæla vindsnið og nema svifryk og aðrar agnir í lofthjúpnum. Veðurstofa Ísland á tvo Doppler agnasjár sem geta veitt samfelldar mælingar á vindhraða og -stefnu, byggðar á Dopplerhrifa, og endurkastsstuðul og tvípólunarhlutfall (e. depolarization ratio) agna. Í þessu verkefni var könnuð notkun Doppler agnasjár á Íslandi til að auka flugöryggi. Verkefninu var skipt niður í þrjá verkþætti: i) ókyrrðarmælingar í ...
|
|---|