Last edited by Dair
Sunday, July 26, 2020 | History

2 edition of Observations of the ultraviolet spectral reflectance of snow found in the catalog.

Observations of the ultraviolet spectral reflectance of snow

Harold W. O"Brien

Observations of the ultraviolet spectral reflectance of snow

by Harold W. O"Brien

  • 62 Want to read
  • 10 Currently reading

Published by Dept. of Defense, Dept. of the Army, Corps of Engineers, Cold Regions Research and Engineering Laboratory in Hanover, N.H .
Written in English

    Subjects:
  • Snow.,
  • Ultraviolet spectroscopy.,
  • Spectrophotometry.

  • Edition Notes

    StatementHarold W. O"Brien ; Cold Regions Research and Engineering Laboratory.
    SeriesCRREL report ; 77-27, CRREL report -- 77-27.
    ContributionsCold Regions Research and Engineering Laboratory (U.S.), United States. Army. Corps of Engineers. Directorate of Facilities Engineering.
    The Physical Object
    Pagination[1], iii, 19 p. :
    Number of Pages19
    ID Numbers
    Open LibraryOL17536223M

    The reflectance curves for firn and glacier ice are interrupted for the larger wavelengths because they would overlap with the reflectance curve of snow. The reflectance curve for dirty glacier ice is also interrupted at the larger wavelengths because reflectance would vary a lot depending on the type and amount of debris. 2. Results. Spectral analysis of pearls originating from two donors, represented by the upper and lower graphs in Figure 1, respectively, showed the same reflectance peak recorded in the UV region at nm, followed by absorptions (converse of reflectance peaks) ranging from to nm, then a second peak in the region of to nm. Figure 1A shows variation of .

    Basic UV-Vis Theory, Concepts and Applications Page 2 of 28 For convenience of reference, definitions of the various spectral regions have been set by the Joint Committee on Nomenclature in Applied Spectroscopy: Region Wavelength (nm) Far ultraviolet Near ultraviolet Visible Near infrared Land Surface Reflectance Using the Minimum Reflectivity Technique • Composite of one -month, same hourly scenes (Rayleigh -corrected reflectance) – finding a dark scene and consider it for surface reflectance. Each scene. Dark pixels from each month’s dataset composite. Aerosol. Cloud. Snow.

    Solar Ultraviolet Spectral Irradiance: – Routine UV Observations • Fun with SOLSTICE – Flare Observations – Mg II Studies – Stellar Occultation Measurements of the Thermosphere – Lunar Ultraviolet Reflectance Measurements. Bill McClintock SORCE Science Meeting Octo 3 SOLSTICE: Science Objectives and Measurements.   A webinar on the use of infrared imagery is also available for viewing. Objective. During this activity you will collect, manipulate, and graph data to understand the properties of light. You will also gain an understanding of the electromagnetic spectrum and reflectance of light by creating your own spectra from your data, and graphing it on the handouts that are provided.


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Observations of the ultraviolet spectral reflectance of snow by Harold W. O"Brien Download PDF EPUB FB2

Get this from a library. Observations of the ultraviolet spectral reflectance of snow. [Harold W O'Brien; United States. Army. Corps of Engineers.; Cold Regions Research and Engineering Laboratory (U.S.)].

Spectral reflectance signatures result from the presence or absence, as well as the position and shape of specific absorption features, of the surface.

Examples of spectral signatures for soils, litter, and vegetation are shown in Figure In the case of vegetation, light absorption by leaf pigments dominates the reflectance spectrum in the visible region (– nm).

We have measured the UV spectral reflectance properties of jarosite [ideal formula: (K,Na)Fe 3+ 3 (SO 4) 2 (OH) 3], hexahydrite [a polyhydrated sulphate; ideal formula: MgSO 4 ⋅6(H 2 O)], and gypsum [ideal formula: CaSO 4 ⋅2(H 2 O)] to assess whether UV observations are also capable of detecting and discriminating these minerals.

The gypsum Cited by: Lowers the albedo and causes snow to have lower reflectance and higher absorption, which leads it to melt. Name one major scientific advance in the study of the crysophere that were a result of satellite observations.

The Moon has been shown to be an extremely stable radiometric reference for calibration and long-term stability measurements of on-orbit sensors. The majority of the previous work on characterizing the lunar reflectance has been in the visible part of the spectrum using ground-based lunar images.

The SOLar-STellar Irradiance Comparison Experiment (SOLSTICE) on Author: Martin Snow, Gregory M. Holsclaw, William E. McClintock, Tom Woods. The variation of snow albedo with wavelength across the solar spectrum from μm in the ultraviolet (UV) to μm in the near infrared (IR) was measured at Amundsen‐Scott South Pole Station during the Antarctic summers of – and – Remote sensing in geology is remote sensing used in the geological sciences as a data acquisition method complementary to field observation, because it allows mapping of geological characteristics of regions without physical contact with the areas being explored.

About one-fourth of the Earth's total surface area is exposed land where information is ready to be extracted. material primarily rocks and minerals emit visible UV radiation.

However UV radiation is largely scattered by earth’s atmosphere and hence not used in field of remote sensing. This is the light, which our eyes can detect. This is the only portion of the spectrum that can be associated with the concept of color.

Blue Green and. observations in the – nm spectral region to retrieve information on the absorption capacity of tropospheric aerosols. OMI-derived information on aerosol absorption includes the UVAerosol Index and absorption optical depth at nm. The other algorithm makes use of the full UV-to-visible OMI spectral coverage to derive spectral.

The spectral albedo of bare (snow-free) sea ice of different thicknesses is shown in figure 6. Figure 6. Spectral albedos of snow-free sea ice, and open water. Broadband solar albedo α is also given.

Ice thickness is given, except for two ice types that were observed only from a helicopter. From fig. 1 of Brandt et al. The largest UV enhancements (>70%) were seen during partly cloudy conditions immediately after the snowfall.

A radiative transfer model was used to quantify the enhancements due to the snow cover and the spectral albedo of the snow under clear‐sky conditions. UV landscape images are generally not very interesting compared to near-IR photographs that show snow-white vegetation and brilliant white clouds against almost black skies.

In a pure UV image taken outdoors, blue skies look bright white, distant objects are usually hazy looking, but everything else looks much like it does in a conventional. For the snow albedo, the crude profile of the snow reflectance spectrum is determined by the complex refractive index of ice, which closely approximates that of liquid water at wavelengths (λ.

Observations in the far ultraviolet (FUV) at wavelengths below ~ nm, which include the H Lyman series and the spectral lines of many other important species, are expected to. Because these absolutely calibrated observations used for the models were obtained at shorter wavelengths (e.g., maximum wavelength from Thuillier et al.

is μm), the computed spectral irradiance in the μm band relies on the physical model of the solar atmosphere derived from those observations and knowledge of absorption and emission.

wavelength has higher energy. In UV-visible spectroscopy, the low-wavelength UV light has the highest energy. In some cases, this energy is sufficient to cause unwanted photochemical reactions when measuring sample spectra (remember, it is the UV component of light that causes sunburn).

Origin of UV-visible spectra. Broad spectral range reflectance imaging spectroscopy (BR-RIS) from the near UV through the mid–infrared (IR) ( to 25, nm or 28, to cm−1) was investigated as an imaging modality to provide maps of organic and inorganic artists’ materials in paintings.

While visible–to–near-IR (NIR) reflectance and elemental x-ray fluorescence (XRF) imaging. The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission will carry into space the Ocean Color Instrument (OCI), a spectrometer measuring at 5 nm spectral resolution in the ultraviolet (UV) to near infrared (NIR) with additional spectral bands in the shortwave infrared (SWIR), and two multi-angle polarimeters that will overlap the OCI spectral range and spatial coverage, i.

Ultraviolet (UV) albedo and UV reflectance are defined, compared and contrasted, to explain their roles and place in studies focusing on UV radiation and exposure measurements, in the context of localised albedo measurement and human UV exposure studies.

This review recommends that the term UV albedo be used when investigating natural horizontal surfaces. Remote sensing is a powerful resource providing snow observations at a large scale.

This study addresses the potential of using Sentinel-2 high-resolution imagery to assess moderate-resolution snow products, namely H10—Snow detection (SN-OBS-1) and H12—Effective snow cover (SN-OBS-3) supplied by the Satellite Application Facility on Support.

4 Factors affecting spectral reflectance measurements Introduction UV/VNIR x 10–9 W/cm 2 /nm/sr @ nm NIR x 10–9 W/cm 2 /nm/sr @ nm NIR x 10–9 W/cm 2 /nm/sr @ nm Weight lbs or kg Calibration Wavelength, reflectance, radiance*, irradiance*.

All calibrations are NIST.The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. The result showed that for a pure snow spectrum, the snow reflectance peaks appeared from visible to nm band locations; there was an obvious absorption valley of snow spectrum near nm wavelength.

Compared with fresh snow, the reflection peaks of the old snow.others, ) and model the spectral reflectance of snow. Figure 2 shows the calculated spectral reflectance of frozen snow for grain-sizes ofand mm.

The modeled spectra show the expected high reflectance from to nm, the strongly grain-size-dependent reflectance from to nm, and the comparatively low reflectance from.