Ammonia, water vapor, and clouds in Jupiter's Equatorial Zone
Abstract
We obtained spectra of Jupiter at 5 microns on February 4, 2017 in support of perijove 4 (PJ4) of the Juno mission currently orbiting Jupiter. Using the NIRSPEC instrument on the Keck telescope, we mapped large areas of Jupiter, including the Equatorial Zone (EQZ). The microwave radiometer on Juno measures the abundance of ammonia as a function of latitude along Juno's north to south track during each perijove. Early Juno results from PJ1 showed an enhancement in NH3 in Jupiter's EQZ, peaking at 360 ppm near 3 degrees North on Jupiter (Li et al. 2017; DOI:10.1002/2017GL073159). Jupiter's 5-micron spectrum is sensitive to NH3, H2O, and cloud structure. Within the EQZ there is significant variation in cloud opacity. We selected regions with maximum 5-micron flux, and thus thinner, but still substantial clouds. One such region was at the southern extent of a chevron centered in the North Equatorial Belt. We first modeled the strength of CH3D lines at 4.66 microns to derive the deep cloud structure. An opaque cloud at 5.5 bars was required to fit these features. Using this cloud model we fit NH3 and H2O absorption lines near 4.96 microns. Preliminary results indicated a saturated H2O profile and 450 ppm NH3 in the chevron feature. We will compare the abundance of NH3 in the chevron to other regions in the EQZ and with measurements of NH3 in the EQZ using the Very Large Array (de Pater et al. 2016; DOI:10.1126/science.aaf2210).
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P33F3885B
- Keywords:
-
- 5704 Atmospheres;
- PLANETARY SCIENCES: FLUID PLANETSDE: 5739 Meteorology;
- PLANETARY SCIENCES: FLUID PLANETSDE: 5754 Polar regions;
- PLANETARY SCIENCES: FLUID PLANETSDE: 6220 Jupiter;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS