Retrievals of the Far Infrared surface emissivity over the Greenland Plateau

Research Article

TITLE: "Retrievals of the Far Infrared surface emissivity over the Greenland Plateau using the Tropospheric Airborne Fourier Transform Spectrometer (TAFTS)."

(See Author List below)

ABSTRACT (Format Edited for easier online viewing)

The Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) measured near surface upwelling and downwelling radiances within the far infrared (FIR) over Greenland during two flights in March 2015. Here we exploit observations from one of these flights to provide in-situ estimates of FIR surface emissivity, encompassing the range 80-535 cm-1.

The flight campaign and instrumental set-up is described as well as the retrieval method, including the quality control performed on the observations. The combination of measurement and atmospheric profile uncertainties means that the retrieved surface emissivity has the smallest estimated error over the range 360-535 cm-1, (18.7-27.8 μm), lying between 0.89 and 1 with an associated error which is of the order ± 0.06.

Between 80 and 360 cm-1, the increasing opacity of the atmosphere, coupled with the uncertainty in the atmospheric state, means that the associated errors are larger and the emissivity values cannot be said to be distinct from 1.

These FIR surface emissivity values are, to the best of our knowledge, the first ever from aircraft-based measurements. We have compared them to a recently developed theoretical database designed to predict the infrared surface emissivity of frozen surfaces. When considering the FIR alone, we are able to match the retrievals within uncertainties.

However, when we include contemporaneous retrievals from the mid infrared (MIR), no single theoretical representation is able to capture the FIR and MIR behaviour simultaneously. Our results point towards the need for model improvement and further testing, ideally including in-situ characterisation of the underlying surface conditions.

LINK: http://onlinelibrary.wiley.com/doi/10.1002/2017JD027328/abstract

CITATION:

Provider: John Wiley & Sons, Ltd
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doi: 10.1002/2017JD027328

TY - JOUR
AU - Bellisario, Christophe
AU - Brindley, Helen E.
AU - Murray, Jonathan E.
AU - Last, Alan
AU - Pickering, Juliet
AU - Chawn Harlow, R.
AU - Fox, Stuart
AU - Fox, Cathryn
AU - Newman, Stuart M.
AU - Smith, Maureen
AU - Anderson, Doug
AU - Huang, Xianglei
AU - Chen, Xiuhong
C8 - 2017JD027328
TI - Retrievals of the Far Infrared surface emissivity over the Greenland Plateau using the Tropospheric Airborne Fourier Transform Spectrometer (TAFTS).
JO - Journal of Geophysical Research: Atmospheres
JA - J. Geophys. Res. Atmos.
SN - 2169-8996
UR - http://dx.doi.org/10.1002/2017JD027328
DO - 10.1002/2017JD027328
SP - n/a
EP - n/a
KW - surface
KW - far infrared
KW - emissivity
KW - 0736 Snow
KW - 1863 Snow and ice
KW - 1855 Remote sensing
KW - 3934 Optical, infrared, and Raman spectroscopy