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Retrievals of High‐Latitude Surface Emissivity Across the Infrared From High‐Altitude Aircraft Flights
Author(s) -
Murray Jonathan E.,
Brindley Helen E.,
Fox Stuart,
Bellisario Christophe,
Pickering Juliet C.,
Fox Cathryn,
Harlow Chawn,
Smith Maureen,
Anderson Doug,
Huang Xianglei,
Chen Xiuhong,
Last Alan,
Bantges Richard
Publication year - 2020
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2020jd033672
Subject(s) - emissivity , remote sensing , infrared , altitude (triangle) , environmental science , satellite , latitude , snow , atmospheric sciences , meteorology , geology , geodesy , optics , physics , mathematics , astronomy , geometry
We present retrievals of infrared spectral surface emissivities spanning the far infrared and mid‐infrared from aircraft observations over Greenland, taken at an altitude of 9.2 km above sea level. We describe the flight campaign, available measurements, and the retrieval method. The principal barriers to reducing uncertainty in the emissivity retrievals are found to be instrumental noise and our ability to simultaneously retrieve the underlying surface temperature. However, our results indicate that using the instrumentation available to us it is possible to retrieve emissivities from altitude with an uncertainty of ~0.02 or better across much of the infrared. They confirm that the far‐infrared emissivity of snow and ice surfaces can depart substantially from unity, reaching values as low as 0.9 between 400 and 450 cm −1 . They also show good consistency with retrievals from the same flight made from near‐surface observations giving confidence in the methodology used and the results obtained for this more challenging viewing configuration. To the best of our knowledge, this is the first time that far‐infrared surface emissivity has been retrieved from altitude and demonstrates that the methodology has the potential to be extended to planned satellite far‐infrared missions.