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We suggest the procedure of building the maps of noctilucent clouds (NLC) zonal and meridional velocity, mean altitude and particle size based on three-color photometry by identical all-sky RGB-cameras separated by 115 km in a…

Atmospheric and Oceanic Physics · Physics 2023-12-15 Oleg S. Ugolnikov

Noctilucent or polar mesospheric clouds have become visually brighter and occurred more frequently during the recent years and decades. The study of possible reasons and relations with climate changes requires data on long-time trends of…

Atmospheric and Oceanic Physics · Physics 2021-12-08 Oleg S. Ugolnikov

A method for measuring the altitude and particle size of noctilucent clouds, based on positioning and photometry from wide-angle three-color cameras, has been developed to determine the three velocity components, particle radius, and its…

Atmospheric and Oceanic Physics · Physics 2026-05-22 Oleg S. Ugolnikov , Olga Yu. Golubeva , Egor O. Ugolnikov

Wide-field polarization measurements of the twilight sky background during the several nights with bright and extended noctilucent clouds in central and northern Russia in 2014 and 2015 are used to build the phase dependence of degree of…

Atmospheric and Oceanic Physics · Physics 2016-05-25 Oleg S. Ugolnikov , Igor A. Maslov , Boris V. Kozelov , Janna M. Dlugach

The results of simultaneous measurements of noctilucent clouds (NLC) position in a number of ground-based locations are presented. Observational data of 14 bright NLC events over 5 years is used for building the altitude maps of cloud…

A sequence of very bright noctilucent clouds (NLC) was observed in central Russia during the last decade of June, 2018. It followed the meteorite impact 300 km southwards from Moscow in the morning of June 21. Polarization measurements of…

Atmospheric and Oceanic Physics · Physics 2020-01-08 Oleg S. Ugolnikov , Igor A. Maslov

The intensive polar stratospheric vortex in the Arctic that shifted to northern Europe in the winter of 2019-2020 caused low temperatures and the frequent occurrence of polar stratospheric clouds followed by a significant decrease in the…

Earth and Planetary Astrophysics · Physics 2021-04-14 Oleg S. Ugolnikov , Boris V. Kozelov , Sergey V. Pilgaev , Alexey V. Roldugin

The simple 3-D radiative transfer model in the atmosphere of the Earth is built for numerical comparison of direct solar radiation and limb scattering background at the definite layer during the deep twilight period at the middle and upper…

Atmospheric and Oceanic Physics · Physics 2025-09-05 Oleg S. Ugolnikov

Polarization measurements of the twilight background with Wide-Angle Polarization Camera (WAPC) are used to detect the depolarization effect caused by stratospheric aerosol near the altitude of 20 km. Based on a number of observations in…

Atmospheric and Oceanic Physics · Physics 2017-05-12 Oleg S. Ugolnikov , Igor A. Maslov

First results of multi-wavelength measurements of the twilight sky background using all-sky camera with RGB-color CCD conducted in spring and summer of 2016 in central Russia (55.2 deg N, 37.5 deg E) are discussed. They show the effect of…

Atmospheric and Oceanic Physics · Physics 2017-02-14 Oleg S. Ugolnikov , Igor A. Maslov

Mesospheric structures identical to summer noctilucent clouds were observed during the nights of December 17-19, 2024 in Siberian Russia. Basing on the available photo data, the mean altitude of the clouds 70.1+-1.5 km was measured by…

Atmospheric and Oceanic Physics · Physics 2025-01-30 Oleg S. Ugolnikov

During the summer season of 2025, noctilucent clouds (NLC) were observed at the latitudes 55-60N from the late May until the late August. A distinct 5-day periodicity in their occurrence emerged following the summer solstice. Analysis of…

The results obtained using my computing program are consistent with the values obtained twenty years ago. It also makes me believe that how to obtain particle size information using the Light Scattering technique needs to be reconsidered.…

Chemical Physics · Physics 2024-06-21 Yong Sun

A method to obtain particle sizes from images that are used for particle tracking velocimetry is proposed. This is an open source method, developed to use together with the open source software OpenPTV. First, the analysis of different…

Fluid Dynamics · Physics 2022-03-25 R. G. Ramirez de la Torre , Atle Jensen

In this paper we show that Sun-viewing images obtained by the Mars Science Laboratory (MSL) Navigation Cameras (Navcam) can be used for retrieving the dust optical depth and constrain the aerosol physical properties at Gale Crater by…

Earth and Planetary Astrophysics · Physics 2020-09-02 H. Chen-Chen , S. Perez-Hoyos , A. Sanchez-Lavega

Magnitudes and color indices in the Vilnius seven-color system are measured for 690 stars down to ~13.2 mag in the area of the North America and Pelican nebulae. Spectral types, absolute magnitudes, color excesses, interstellar extinctions…

Astrophysics · Physics 2007-05-23 V. Laugalys , V. Straizys

Tomography aims to recover a three-dimensional (3D) density map of a medium or an object. In medical imaging, it is extensively used for diagnostics via X-ray computed tomography (CT). Optical diffusion tomography is an alternative to X-ray…

Computational Physics · Physics 2020-05-26 Aviad Levis , Yoav Y. Schechner , Anthony B. Davis , Jesse Loveridge

Information about size and shape of particles produced in various manufacturing processes is very important for process and product development because design of downstream processes as well as final product properties strongly depend on…

Data Analysis, Statistics and Probability · Physics 2014-11-04 Okpeafoh S. Agimelen , Peter Hamilton , Ian Haley , Alison Nordon , Massimiliano Vasile , Jan Sefcik , Anthony J. Mulholland

The paper contains the results of wide-angle polarization camera (WAPC) measurements of the twilight sky background conducted in summer 2011 and 2012 at 55.2 degs.N, 37.5 degs.E, southwards from Moscow. The method of single scattering…

Atmospheric and Oceanic Physics · Physics 2015-06-12 Oleg S. Ugolnikov , Igor A. Maslov

The Northern Sky Variability Survey (NSVS) is a temporal record of the sky over the optical magnitude range from 8 to 15.5. It was conducted in the course of the first generation Robotic Optical Transient Search Experiment (ROTSE-I) using a…

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