Physics
Scientific paper
Oct 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011epsc.conf...18k&link_type=abstract
EPSC-DPS Joint Meeting 2011, held 2-7 October 2011 in Nantes, France. http://meetings.copernicus.org/epsc-dps2011, p.18
Physics
Scientific paper
Imaging of Neptune by the Hubble Space Telescope (HST) between 1994 and 2010 using 583 images in 18 filters reveals changes on Neptune over time scales an hour to a decade in atmospheric levels spread over more than four scale heights. The fastest change occurred with discrete clouds on time scales of hours, but their general activity changed only on a time scale of about 5 years. Discrete clouds are located near the tropopause (0.13 bars). The top two scale heights of the tropopause were probed in methane bands, revealing no temporal change throughout the observation period. A major dark bands around 10º latitude and a minor one around -70º latitude were either particular clear regions or regions of high methane humidity. The following scale height down probed best in weak methane absorptions had more than 10 times as much haze as at higher altitudes. This haze had only a minor latitudinal structure. No change was detectable throughout the observation period. The deeper levels of Neptune could only be probed in continuum wavelengths in the visible, best with a blue filter. These levels changed considerably, but at a slow pace. Almost everywhere and almost always, these levels brightened. The brightening speed decayed exponentially with a 5 year time scale. This brightening is interpreted by dark aerosols settling to deeper altitudes at a speed corresponding to 1 bar per year, and getting replaced by bright aerosols settling down from higher altitudes. The contrast of single scattering albedos between both types of aerosols is a constant 0.03-0.04 throughout the probed spectrum in the visible. By the end of the observation period, the dark haze had settled to levels roughly below 15 bars, at which point they could not be probed any more. This left a continuous haze layer of bright haze below the 1.4- bar level. There is one exception to this general brightening. Between 1994 and 1996, and between 15 and 30 deg latitude, the low levels on Neptune darkened. Presumably, dark material from low altitudes was brought up by a dynamical process.
No associations
LandOfFree
Neptune's Dark Haze Settling Slowly to Lower Altitudes between 1994 and 2010 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Neptune's Dark Haze Settling Slowly to Lower Altitudes between 1994 and 2010, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Neptune's Dark Haze Settling Slowly to Lower Altitudes between 1994 and 2010 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1655266