Ammonia Clouds of Jupiter and Saturn - Here Today, Gone Tomorrow?

Details Ammonia Clouds of Jupiter and Saturn - Here Today, Gone Tomorrow? Ammonia Clouds of Jupiter and Saturn - Here Today, Gone Tomorrow?

Dec 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003agufm.a12a0072a&link_type=abstract

American Geophysical Union, Fall Meeting 2003, abstract #A12A-0072

Physics

0300 Atmospheric Composition And Structure, 0343 Planetary Atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 6207 Comparative Planetology, 6220 Jupiter, 6275 Saturn

Scientific paper

Ground-based, satellite, and spacecraft observations show that, with the exception of some relatively clear regions (belts, hot spots, warm areas), clouds exist everywhere on Jupiter and Saturn. Thermochemical models (Atreya et al., 1999) combined with observational evidence (e.g. Galileo NIMS obiter imaging, Banfield, et al., 1998; Galileo probe data, Atreya et al., 1999, 2003a) suggest that the composition of the upper cloud layer of Jupiter and Saturn is ammonia. Yet, spectrally identifiable ammonia clouds (SIAC) are detected only in certain discrete regions of Jupiter (Baines et al., 2002; Wong, et al., 2003a) and nowhere on Saturn. Less than 1% of Jupiter's area is covered with SIACs according to Galileo NIMS observations (Baines et al., 2002). In this work, we argue that spectral signature of all but the freshly made SIACs is masked by dusting of the ammonia clouds by photochemically produced hydrocarbon haze falling from the stratosphere (Atreya et al., 2003b). We estimate the deposition rate of the coating haze layer to be at least 100 A/year on Jupiter, enough to turn the ammonia cloud into a spectrally grey cloud. The haze particles are composed mostly of condensed polycyclic aromatic hydrocarbons (Wong, et al., 2003b), with smaller contribution from polyyne polymers, nitrile polymers, solid hydrazine and meteoritic dust. Cloud properties including cloud opacity, cloud top height, and the particle size can also be a factor in the lack of detection of ammonia clouds. The lack of spectral identification of Saturn's ammonia clouds can also be explained similarly. References: Atreya et al., Planet. Space Sci., 47, 1243, 1999. Atreya et al., Planet. Space Sci., 51, 105, 2003a. Atreya et al., Jupiter's ammonia clouds-Localized or ubiquitous? Planet. Space Sci., submitted, 2003b. Baines et al., Icarus, 159, 74, 2002. Banfield et al., Icarus, 135, 230, 1998. Wong, M.H., et al., PSS, in press, 2003a. Wong A.S., et al., GRL, 30, art. no. 1447, 2003b.

Affiliated with

Also associated with

No associations

Rating

Ammonia Clouds of Jupiter and Saturn - Here Today, Gone Tomorrow? 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 Ammonia Clouds of Jupiter and Saturn - Here Today, Gone Tomorrow?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ammonia Clouds of Jupiter and Saturn - Here Today, Gone Tomorrow? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1424444