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| Titel |
Infrared measurements in the Arctic using two Atmospheric Emitted Radiance Interferometers |
| VerfasserIn |
Z. Mariani, K. Strong, M. Wolff, P. Rowe, V. Walden, P. F. Fogal, T. Duck, G. Lesins, D. S. Turner, C. Cox, E. Eloranta, J. R. Drummond, C. Roy, D. D. Turner, D. Hudak, I. A. Lindenmaier |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 5, no. 2 ; Nr. 5, no. 2 (2012-02-06), S.329-344 |
| Datensatznummer |
250002461
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| Publikation (Nr.) |
 copernicus.org/amt-5-329-2012.pdf |
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| Zusammenfassung |
| The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) is a
moderate resolution (1 cm−1) Fourier transform infrared spectrometer
for measuring the absolute downwelling infrared spectral radiance from the
atmosphere between 400 and 3000 cm−1. The extended spectral range of
the instrument permits monitoring of the 400–550 cm−1 (20–25 μm)
region, where most of the infrared surface cooling currently occurs in the
dry air of the Arctic. Spectra from the E-AERI have the potential to provide
information about radiative balance, trace gases, and cloud properties in
the Canadian high Arctic. Calibration, performance evaluation, and
certification of the E-AERI were performed at the University of Wisconsin
Space Science and Engineering Centre from September to October 2008. The
instrument was then installed at the Polar Environment Atmospheric Research
Laboratory (PEARL) Ridge Lab (610 m altitude) at Eureka, Nunavut, in October
2008, where it acquired one year of data. Measurements are taken every seven
minutes year-round, including polar night when the solar-viewing
spectrometers at PEARL are not operated. A similar instrument, the
University of Idaho's Polar AERI (P-AERI), was installed at the
Zero-altitude PEARL Auxiliary Laboratory (0PAL), 15 km away from the PEARL
Ridge Lab, from March 2006 to June 2009. During the period of overlap, these
two instruments provided calibrated radiance measurements from two
altitudes. A fast line-by-line radiative transfer model is used to simulate
the downwelling radiance at both altitudes; the largest differences
(simulation-measurement) occur in spectral regions strongly influenced by
atmospheric temperature and/or water vapour. The two AERI instruments at
close proximity but located at two different altitudes are well-suited for
investigating cloud forcing. As an example, it is shown that a thin, low ice
cloud resulted in a 6% increase in irradiance. The presence of clouds
creates a large surface radiative forcing in the Arctic, particularly in the
750–1200 cm−1 region where the downwelling radiance is several times
greater than clear-sky radiances, which is significantly larger than in
other more humid regions. |
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