SpectralEmissivity & Emittance

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Raytek’s Spectral Emissivity Table for Non-metals

The Raytek North America website includes a table for the emissivity of a large range of non-metallic materials that includes common building materials, ceramics, glasses and natural materials including ice & water in as many as four wavelength regions.

Wavebands covered include 1.0 micrometer (micron), 5.0 microns, 7.9 microns and the 8-14 micron band. No specific data and the limits of the various wavebands and there are many instances where the wavelength region is labelled as “nr” meaning “Not Recommended”.

IR Emissivity Data on Vegetation at the MODIS Emissivity Library

Data available includes 24 sample of vegetation ranging from the Leaf of the Algerian Ivy (Hedera canariensis algerian ivy) to the Leaf of Sweet Gum tree (liquidamber styreciflua), one sample of bark of the Eucalyptus tree and three sample of dry grass.

Commentary of the site data reads:

Vegetation Green vegetation typically has a very high emissivity because it is structured and contains water. Senescent (dry) vegetation has a more variable emissivity, especially in the 3 to 5 µm region, which depends on the type and structure of the cover type, the dryness, and so forth.”

IR Emissivities of Soils and Sands at the MODIS UCSB Emissivity Library

Data is provided on: 9 samples of Nebraska Soil Lab, 14 samples of Oklahoma Soil, 10 samples of Death Valley, CA Soil, 10 samples of Railroad Valley, Nevada playa Soil, 2 samples of Railroad Valley, NV soil powder, 6 samples of Koehn, CA, 3 samples of Concord MA Soil, 9 samples of Page Arizona Sandy Soil, 2 samples of Goleta , CA Beach Sand, 3 samples of Soil – Prepared by ICESS, and more.

Commentary of the data reads:

Soil and Sands exhibit stronger spectral features than many others. The “restralen” bands of quartz sand cause strong spectral features between 8 and 10 microns that depend on the grain size. The signature in the 3 to 5 µm region depends strongly on the water and organic content. The dryer, purer soils have lower emissivities in this region.”