Visibility and Cloud Height

2001 ◽  
Author(s):  
Fred V. Brock ◽  
Scott J. Richardson
Keyword(s):  
Remote Sensing ◽  
Red Light ◽  
Moderate Intensity ◽  
Atmospheric Transparency ◽  
Cloud Height ◽  
Meteorological Systems ◽  
Human Eyes ◽  
The Way

Visibility measurement is the most human-oriented measurement discussed because the objective of such measurement is to determine the distance at which humans (pilots, seamen, etc.) can see objects. Thus we are concerned with light that can be seen by humans (0.4 to 0.7μm), the way human eyes perceive such light, and then with the transparency of the atmosphere. Throughout this chapter, in the discussion of atmospheric transparency or absorption, the range of wavelengths from 0.4 (violet) to 0.7μm (red light) will be assumed. Cloud height is a remote sensing measurement but is included here because airport meteorological systems usually include a cloud height sensor. According to the WMO, meteorological visibility by day is defined as the greatest distance that a black object of suitable dimensions, situated near the ground, can be seen and recognized when observed against a background of fog, sky, etc. Visibility at night is defined as the greatest distance at which lights of moderate intensity can be seen and identified.

scholarly journals Foreword to the Special Issue on Paving the Way for the Future of Urban Remote Sensing

2020 ◽  
Vol 13 ◽  
pp. 6533-6536
Author(s):  
Sebastien Lefevre ◽  
Thomas Corpetti ◽  
Monika Kuffer ◽  
Hannes Taubenbock ◽  
Clement Mallet
Keyword(s):  
Remote Sensing ◽  
Special Issue ◽  
Urban Remote Sensing ◽  
The Future ◽  
The Way

World without colour and its photographs and optical images

2020 ◽  
Vol 11 (1-2) ◽  
pp. 79-97
Author(s):  
Reza Tavakol
Keyword(s):  
Electromagnetic Waves ◽  
Coarse Grained ◽  
Visible Range ◽  
Optical Images ◽  
Cosmological Observations ◽  
The World ◽  
Visual Index ◽  
Different Origins ◽  
Human Eyes ◽  
The Way

Photographs and optical images, whatever their contents, are imprints of the electromagnetic waves in the (human) visible range of wavelengths, we refer to as light. Furthermore, they are designed to portray different parts of the visible light in terms of different colours, in analogy with the human eyes, however imperfectly. The world outside our eyes and cameras, however, is permeated by electromagnetic waves with much wider spectrum of wavelengths than those in the visible range. Importantly also, colour is a construct of our eye–brains: the Universe itself has no colour, independently of us. I ask how does the knowledge of these facts change the way we perceive the colour in optical images and photographs, whatever their relationship to the world in a representational sense may be? By employing three images, with very different origins and vistas – one a direct photograph, the other two synthetically constructed images using real cosmological observations – I demonstrate the extent to which colour in such images can hide the underlying phenomena of which they claim to visually speak, both due to its nature as a coarse-grained visual index, and by being restricted to the visible range. The aim is not to belittle the important role that our (restricted) vision together with our perception of colour have played in the evolution of our species, and still play in the way we relate to the world informationally, aesthetically and emotionally. But rather to show that recognizing the limitations of our vision and complementing it with the knowledge of the phenomena underlying optical images and photographs can allow us to perceive them anew and provide additional tools (both conceptual and visual) to imagine and envision such images outside the bounds of the visible range and colour.

The Philosophy of Artistic Creation: Phidias, the Ideas, and Cicero

Apeiron ◽  
2018 ◽  
Vol 51 (3) ◽  
pp. 325-344 ◽  
Author(s):  
Anna Motta
Keyword(s):  
Point Of View ◽  
Artistic Creation ◽  
Platonic Theory ◽  
Human Eyes ◽  
Human Hands ◽  
The Way

Abstract Since Antiquity Phidias seems to be the best sculptor of Gods, because he carved great statues with his human hands and succeeded in giving a physical look to that which is not visible to human eyes. This paper is devoted to Cicero’s attention on the imaginative creation of the artist and on the philosophical features of that demiurgical activity which the Roman philosopher links to his interpretation of the Platonic theory of the Forms. The survey led on some Ciceronian texts shows, from a philosophical and philological point of view, the way in which Cicero reconsiders the role of the phantasia, offering a revalution of the art.

scholarly journals Red Light for the Sand Lizard in Britain

Oryx ◽  
1969 ◽  
Vol 10 (2) ◽  
pp. 89-90 ◽  
Author(s):  
K. Corbett
Keyword(s):  
Protected Areas ◽  
Sand Dunes ◽  
Red Light ◽  
Full Time ◽  
In Captivity ◽  
Sand Lizard ◽  
The Way

The sand lizard in Britain is well on the way to extinction, thanks to the destruction of its favoured habitats – sand dunes and dry heath. The author, who has been engaged in full-time research on the surviving populations, has started breeding sand lizards in captivity, using animals taken from sites that are being destroyed, and hopes to reintroduce them in protected areas.

Remote sensing and GIS paves the way for depth of cover pipeline analysis

2021 ◽  
Author(s):  
Ulrich Michel ◽  
Simon Daniels ◽  
Daniel Finley
Keyword(s):  
Remote Sensing ◽  
Remote Sensing And Gis ◽  
The Way

scholarly journals Characterization of FIREFLY, an Imaging Spectrometer Designed for Remote Sensing of Solar Induced Fluorescence

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4682
Author(s):  
Ian Paynter ◽  
Bruce Cook ◽  
Lawrence Corp ◽  
Jyoteshwar Nagol ◽  
Joel McCorkel
Keyword(s):  
Remote Sensing ◽  
Shot Noise ◽  
Dark Current ◽  
Red Light ◽  
Light Yield ◽  
Stray Light ◽  
Integrating Sphere ◽  
Oxygen Absorption ◽  
Detector Response ◽  
Absorption Features

Solar induced fluorescence (SIF) is an ecological variable of interest to remote sensing retrievals, as it is directly related to vegetation composition and condition. FIREFLY (fluorescence imaging of red and far-red light yield) is a high performance spectrometer for estimating SIF. FIREFLY was flown in conjunction with NASA Goddard’s lidar, hyperspectral, and thermal (G-LiHT) instrument package in 2017, as a technology demonstration for airborne retrievals of SIF. Attributes of FIREFLY relevant to SIF retrieval, including detector response and linearity; full-width at half maximum (FWHM); stray light; dark current; and shot noise were characterized with a combination of observations from Goddard’s laser for absolute measurement of radiance calibration facility; an integrating sphere; controlled acquisitions of known targets; in-flight acquisitions; and forward modelling. FWHM, stray light, and dark current were found to be of acceptable magnitude, and characterized to within acceptable limits for SIF retrieval. FIREFLY observations were found to represent oxygen absorption features, along with a large number of solar absorption features. Shot noise was acceptable for direct SIF retrievals at native resolution, but indirect SIF retrievals from absorption features would require spatial aggregation, or repeated observations of targets.

Managing plant invasions through the lens of remote sensing: A review of progress and the way forward

2018 ◽  
Vol 642 ◽  
pp. 1328-1339 ◽  
Author(s):  
Ana Sofia Vaz ◽  
Domingo Alcaraz-Segura ◽  
João C. Campos ◽  
Joana R. Vicente ◽  
João P. Honrado
Keyword(s):  
Remote Sensing ◽  
Plant Invasions ◽  
The Way

scholarly journals THz generation from laser-induced breakdown in pressurized molecular gases: on the way to terahertz remote sensing of the atmospheres of Mars and Venus

2020 ◽  
Vol 22 (1) ◽  
pp. 013039 ◽  
Author(s):  
Peter M Solyankin ◽  
Irina A Nikolaeva ◽  
Andrey A Angeluts ◽  
Daniil E Shipilo ◽  
Nikita V Minaev ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Molecular Gases ◽  
Thz Generation ◽  
Laser Induced Breakdown ◽  
The Way
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