Identification of Jupiter's 10-μ m Ammonia Ice Feature in CIRS Data

Details Identification of Jupiter's 10-μ m Ammonia Ice Feature in CIRS Data Identification of Jupiter's 10-μ m Ammonia Ice Feature in CIRS Data

May 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003dps....35.4806w&link_type=abstract

American Astronomical Society, DPS meeting #35, #48.06; Bulletin of the American Astronomical Society, Vol. 35, p.1014

Other

Scientific paper

We present the first detection of NH3 ice in the thermal infrared in Jupiter's atmosphere using Cassini CIRS observations in the 10-μ m region obtained on 31 December 2000 and 1 January 2001.
We quantify the strength of the NH3 ice feature by calculating a brightness temperature difference α defined by subtracting the brightness temperature at 1060 cm-1 from the brightness temperature of an adjacent continuum region at 1040 cm-1. Using midlatitude zonally averaged CIRS spectra, we demonstrate systematic spatial variations in α , with the highest values (implying a stronger NH3 ice signature) at the equator and near 23o N.
In one CIRS spectral average (covering 22o to 25o N and 140o to 240o W), our models indicate an optical depth of 0.75+/-0.25 for NH3 ice particles modeled as randomly oriented 4:1 prolate spheroids (volume equivalent radius = 0.79 μ m). We choose prolate spheroid particles based on laboratory studies of NH3 ice aerosols, although 1-μ m Mie-scattering spheres would also have detectable signatures at 1060 cm-1. Particles larger or smaller than 1 μ m by a factor of 2 or more would be unable to duplicate the observed NH3 ice feature at 1060 cm-1: absoprtion due to larger particles is excessively broadened, and absorption due to smaller particles is hidden by NH3 gas absorption at 1067 cm-1. In a spectrum of a second region on Jupiter (14o to 17o N and 10o to 70o W), we find an upper limit of τ = 0.2 for the same NH3 ice particle type.
In our models, the 1060 cm-1 feature appears only when NH3 ice is present at P <= 500 mbar, suggesting that the detected particles are distinct from the deeper higher-opacity grey cloud required to match data from both CIRS and other previous infrared studies.

Affiliated with

Also associated with

No associations

Rating

Identification of Jupiter's 10-μ m Ammonia Ice Feature in CIRS Data 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 Identification of Jupiter's 10-μ m Ammonia Ice Feature in CIRS Data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Identification of Jupiter's 10-μ m Ammonia Ice Feature in CIRS Data will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1523463