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The Far-INfrarEd Spectrometer for Surface Emissivity (FINESSE) Part II: first measurements of the emissivity of water in the far-infrared
File(s)
amt-17-4777-2024.pdf (8.42 MB)
Published version
Author(s)
Warwick, Laura
Murray, Jonathan
Brindley, Helen
Type
Journal Article
Abstract
In this paper we describe a method for retrieving surface emissivity across the wavenumber range 400–1600 cm-1 using novel radiance measurements from the Far INfrarEd Spectrometer for Surface Emissivity (FINESSE) instrument. FINESSE is described in detail in part I of this paper. We apply the method to two sets of measurements of distilled water. The first set of emissivity retrievals is of distilled water heated above ambient temperature to enhance the signal to noise ratio. The second set of emissivity retrievals is of ambient temperate water at a range of viewing angles. In both cases the observations agree well with calculations based on compiled refractive indices across the mid and far-infrared. It is found that the reduced contrast between the up and downwelling radiation in the ambient temperature case degrades the performance of the retrieval. Therefore a filter is developed to target regions of high contrast which improves the agreement between the ambient temperature emissivity retrieval and the predicted emissivity. These retrievals are, to the best of our knowledge, the first published 10 retrievals of the emissivity of water that extend into the far-infrared and demonstrate a method that can be used for the in-situ retrieval of the emissivity of other surfaces in the field.
Date Issued
2024-08
Date Acceptance
2024-06-29
Citation
Atmospheric Measurement Techniques, 2024, 17 (16), pp.4777-4787
URI
URL
DOI
ISSN
1867-1381
Publisher
Copernicus Publications
Start Page
4777
End Page
4787
Journal / Book Title
Atmospheric Measurement Techniques
Volume
17
Issue
16
Copyright Statement
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
License URL
Identifier
https://doi.org/10.5194/amt-17-4777-2024
Publication Status
Published
Date Publish Online
2024-08-19