Uranus's northern polar cap in 2014.
Geophys Res Lett
; 45(11): 5329-5335, 2018 Jun 16.
Article
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| ID: mdl-32546873
ABSTRACT
In October and November 2014, spectra covering the 1.436 - 1.863-µm wavelength range from the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope showed the presence of a vast bright North polar cap on Uranus, extending northward from about 40°N and at all longitudes observed. The feature, first detected in August 2014 from Keck telescope images, has a morphology very similar to the southern polar cap that was seen to fade before the 2007 equinox. At strong methane-absorbing wavelengths (for which only the high troposphere or stratosphere is sampled) the feature is not visible, indicating that it is not a stratospheric phenomenon. We show that the observed northern bright polar cap results mainly from a decrease in the tropospheric methane mixing ratio, rather than from a possible latitudinal variation of the optical properties or abundance of aerosol, implying an increase in polar downwelling near the tropopause level.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Geophys Res Lett
Año:
2018
Tipo del documento:
Article
País de afiliación:
Reino Unido