 |
| Titel |
Contiguous polarisation spectra of the Earth from 300 to 850 nm measured by GOME-2 onboard MetOp-A |
| VerfasserIn |
L. G. Tilstra, R. Lang, R. Munro, I. Aben, P. Stammes |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 7 ; Nr. 7, no. 7 (2014-07-09), S.2047-2059 |
| Datensatznummer |
250115843
|
| Publikation (Nr.) |
 copernicus.org/amt-7-2047-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| In this paper we present the first contiguous high-resolution
spectra of the Earth's polarisation observed by a satellite
instrument. The measurements of the Stokes fraction Q/I are
performed by the spectrometer GOME-2 onboard the
MetOp-A satellite. Polarisation measurements by
GOME-2 are performed by onboard polarisation measurement
devices (PMDs) and the high-resolution measurements discussed in
this paper are taken in the special "PMD RAW" mode of
operation. The spectral resolution of these PMD RAW polarisation
measurements varies from 3 nm in the ultraviolet (UV) to
35 nm in the near-infrared wavelength range. We first
compare measurements of the polarisation from cloud-free scenes with
radiative transfer calculations for a number of cases. We find good
agreement but also a spectral discrepancy at 800 nm, which
we attribute to remaining imperfections in the calibration key
data. Secondly, we study the polarisation of scenes with special
scattering geometries that normally lead to near-zero Q/I. The
GOME-2 polarisation spectra indeed show this behaviour and
confirm the existence of the small discrepancy found
earlier. Thirdly, we study the Earth polarisation for a variety of
scenes. This provides a blueprint of Q/I over land and sea
surfaces for various degrees of cloud cover. Fourthly, we compare
the spectral dependence of measurements of Q/I in the UV with the
generalised distribution function proposed by Schutgens
and Stammes (2002) to describe the shape of the UV polarisation
spectrum. The GOME-2 data confirm that these functions match
the spectral behaviour captured by the GOME-2 PMD RAW mode. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|