Saturday, April 09, 2005

LPSC Notes Part Two

After some delay, here is the second half of my notes from LPSC:
  • Cassini RADAR
    • Radiometry
      • not an iceball
      • dielectric constant ~ 2.1
      • a lot going on
      • N-S gradient, 2.1 in north, 1.6 in south
      • organic material ~ 2-3
    • Scatterometry Ta inbound
      • multiple populations of terrain types
      • coorelate w/ optical albedo
      • optically dark -> radar dark -> warmer
      • optically bright -> radar bright -> cooler
    • High resolution radiometry
      • bland dark - higher brightness temperature
      • argues for importance of volume scattering role of organic contaminents
      • Xanadu - mottled
    • RADAR dark features in plains - smooth, localized
      • kitty head - 56W, 50N
      • west ponds in Ta - 124W, 37N
    • Ganesa Macula
      • cryovolcanic dome akin to pancake domes on Venus
      • degraded topography along margins
      • deltas connected to bright lines
      • rough center - pit
    • Cryovolcanic features - 43W, 49N, 40 km caldera
  • VIMS - Bob Brown
    • Phoebe
      • compositionally diverse
      • water everywhere (bound or free)
      • ferrous iron
      • 2.2 micron absorption - cyanides
      • 3.3 micron absorption - C-H organics
      • CO2 - complex inclusion in minerals - found in dark materials
      • a bit more ice at the poles
    • Titan
      • emission at 1500 km - atmosphere more extended than once thought
      • snail - geology from VIMS possible
  • CIRS
    • Detected species - CO, N2, CH4, C3H4, H2, C4H2, CO2, C2H2, C2H6, C2H4, CH3D
    • Stratosphere - 310 km - max temp
    • upwelling at southern latitudes w/ adiabatic cooling
    • circumpolar vortex in north - high winds in north
    • wind jets change with seasons
    • zonal variations in temperature weak
    • HCN seen at high northern latitudes
    • CO2 disappears as you move north
    • CO2 increases with depth
    • winter polar atmosphere isolated - akin to terrestrial ozone hole
    • strongest winds 160 m/s at 20-40N
    • summer pole 5K colder than equator in the stratosphere
    • CO stratospheric mole fraction 4.5 +/- 1.5 x 10-5
    • CH4 mole fraction in statosphere 1.6 +/- 0.5 x 10-2
  • UVIS
    • Instruments
        FarUV (110-190 nm)
      • EUV (55-110 nm, solar occultations as well
      • High speed photometer
      • HDAP (D/H ratio)
    • Tb Stellar Occultations
      • Lambda Sco + Spica
      • vertical profile of constituents
      • Lambda Sco - 36 South Latitude
      • CH4, N2, C2H2, C2H4, C2H6, HCN, C4H2
    • Tmin - 114 K near 615 km
    • Phoebe
      • H2O, CO2, frosts contribute to Phoebe' FUV spectrum
      • latitudinal variations
      • no emissions (not Chiron)
      • very dark <>
    • ion composition
      • No N+ near Titan
      • maybe it comes from icy satellites
      • O2 atmosphere over rings
      • H2/O2 loss rate ~10
  • Magnetometer
    • magnetospheric interaction with Enceladus similar to Io and Jupiter
    • Saturn's magnetic field is being bent around moon
    • either very dense atmosphere or higher production of ions
    • wave activity H2O+ - Alfven wing
    • 2 Re extent
    • no firm density number
  • Aerosol and Cloud Properties from DISR
    • 8 particles/cm3 rather uniform assumes 256 monomers/particle and 0.05 micron monomer size
    • HRI images with lamp on - backscatter off haze
    • optical depth @ 830 nm @ surface 1.5
    • optical depth @ 531 nm @ surface - 6
    • aerosols larger than thought
    • aerosols extend to the ground

4 Comments:

Anonymous remco de kok said...

Hi Jason,

I'm a bit puzzled by these statements from the CIRS talk:

CO2 disappears as you move north
CO2 increases with depth

Who gave the talk? Mike Flasar?
What evidence was shown for these statements? any more info?

Thanks a bunch!

4/11/2005 01:44:00 AM  
Blogger Jason said...

I can't find any more in my notes here. Remember, CIRS has so far only probed the stratosphere of Titan, not any lower. The vertical distribution likely comes from limb scans while the north-south distribution likely comes from the Nadir scans.

4/11/2005 11:51:00 AM  
Anonymous remco de kok said...

nadir observations show a slight increase (if any change at all) in CO2 as you go north

and you expect the abundance to increase with altitude

hmmmm...

did it have a picture with the ratio of the radiance at different lattitudes?

4/12/2005 06:50:00 AM  
Blogger Jason said...

..., I can always be wrong but that's what I have in my notes. The talk was given by Mike as far as I know.

4/12/2005 10:08:00 AM  

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